فهرست مطالب morteza behnam-rassouli

Alzheimer’s disease is one of the most common dementias, which is initially characterized by synaptic damage and subsequently accompanied by neuronal loss and cognitive impairments, such as anxiety and depression. Urolithins are natural phenolic compounds found abundantly in the human diet and are catabolized from the hydrolysis of ellagitannins by the gut microbiota. They possess anti-inflammatory and antioxidant properties and have been found to be effective in brain disorders, particularly memory dysfunction. This study aimed to investigate the effect of Urolithin A and B administration on learning and memory impairments as well as anxiety-like behaviors in adult male rat models of Alzheimer’s disease.

In this experimental study, 70 adult male Wistar rats were randomly divided into 10 groups of seven, including the healthy control group, the Sham group: received streptozotocin solvent (ascorbic acid 0.1% in saline) as intracerebroventricular (ICV) injection and urolithins solvent (DMSO) as intraperitoneal (IP) injection, Positive control group: received streptozotocin as ICV injection and memantine as IP injection, Negative control group: received streptozotocin as ICV injection, Treatment groups 1 to 6: received streptozotocin as ICV injection and urolithin A and urolithin B as IP injection for 14 days. After the treatment period, the learning and memory of the rats were measured by the passive avoidance test, and the elevated plus maze test measured anxiety-like behaviors.

The results of statistical analysis using one-way variance test (ANOVA) and Tukey's post hoc test, performed in R software, showed that in the passive avoidance test, streptozotocin caused a significant impairment in learning and memory in the negative control group (P<0.01), while the treatment with urolithin A and B significantly improved memory performance, much better than the standard treatment (memantine) (P<0.05). Furthermore, the results of the elevated plus maze test also indicated a significant increase in anxiety-like behaviors in the negative control group compared to the control group (P<0.001), while the treatment with urolithin A and B significantly reduced these behaviors (P<0.01).

The results of this study indicated that urolithin A and B, probably due to their antioxidant and anti-inflammatory properties, protected the brain against the effects of streptozotocin injection, and consequently, improved learning and memory performance and reduced anxiety-like behaviors.

The reduced organ function following delayed nerve repair highlights the need for pharmacological interventions. In this regard, many chemical agents have been administered after nerve injury; however, their functional outcomes are not satisfying yet. The present study aimed to evaluate the effects of the administration of citicoline and atorvastatin on the regenerative capacity of the distal end of the transected sciatic nerve throughout a delayed nerve repair period.

The sciatic nerve of male rats (250-300 g) was transected, and the animals were intraperitoneally administrated citicoline (200 mg/kg, n=5), atorvastatin (5 mg/kg, n=5), citicoline + atorvastatin, and vehicles (control groups 1 and 2, n=5) for one month. In the sham group (n=5), the sciatic nerve was only exposed. After one month, the transected nerve was repaired. Fourteen weeks after surgical repair, morphometric and electron microscopic evaluations were performed on the nerve.

In the present study, improvement in the structural (fiber diameter, axon diameter, and myelin thickness, etc.) and ultrastructural (degree of myelin destruction) indices of the distal segment of the nerve was observed in the citicoline and atorvastatin groups compared to the control groups (P< 0.01). In addition, the nerve structural and ultrastructural indices in the citicoline + atorvastatin group were better than each citicoline and atorvastatin group.

The results of this study showed that the administration of citicoline and atorvastatin leads to maintaining the regeneration capacity of the distal part of the nerve in the condition of delayed nerve repair

In this study, the impact of thiamine (Thi), N-acetyl cysteine (NAC), and dexamethasone (DEX) were investigated in axotomized rats, as a model for neural injury.

Sixty-five axotomized rats were divided into two different experimental approaches, the first experiments included five study groups (n=5): intrathecal Thi (Thi.it), intraperitoneal (Thi), NAC, DEX, and control. Cell survival was assessed in L5DRG in the 4th week by histological assessment. In the second study, 40 animals were engaged to assess Bcl-2, Bax, IL-6, and TNF-α expression in L4-L5DRG in the 1st and 2nd weeks after sural nerve axotomy under treatment of these agents (n=10).

Ghost cells were observed in morphological assessment of L5DRG sections, and following stereological analysis, the volume and neuronal cell counts significantly were improved in the NAC and Thi.it groups in the 4th week (P<0.05). Although Bcl-2 expression did not show significant differences, Bax was reduced in the Thi group (P=0.01); and the Bcl-2/Bax ratio increased in the NAC group (1st week, P<0.01). Furthermore, the IL-6 and TNF-α expression decreased in the Thi and NAC groups, on the 1st week of treatment (P≤0.05 and P<0.01). However, in the 2nd week, the IL-6 expression in both Thi and NAC groups (P<0.01), and the TNF-α expression in the DEX group (P=0.05) were significantly decreased. 

The findings may classify Thi in the category of peripheral neuroprotective agents, in combination with routine medications. Furthermore, it had strong cell survival effects as it could interfere with the destructive effects of TNF-α by increasing Bax.

Pharmacotherapy is a cheap, accessible and non-invasive treatment that can be used in the first hours after the nerve injury. Although using some drugs after nerve injury accelerates the nerve repair process. But their functional outcomes are still not satisfactory. Therefore, the aim of the present study was to evaluate the effects of methylprednisolone (MP) administration on maintaining the regenerative capacity of the distal segment of the transected sciatic nerve in conditions of delayed nerve repair.

The sciatic nerve of male rats (250-300 g) was transected and the animals were interaperitoneally administrated MP succinate (2 mg/kg, n=8) and saline (control group, n=8) for 1 month. In the sham group (Control group, n=5), the sciatic nerve was only exposed. After 1 month, the transected nerve was repaired. Fourteen weeks after surgical repair, morphometric and electron microscopic evaluations were performed on the nerve.

In the present study, the mean axonal cross-section area, myelinated fiber diameter, axonal diameter and myelin thickness were significantly higher in the MP distal segment compared to that of the control group (P<0.01). Also, the majority of the fibers in the MP group had a normal myelin sheath and normal Schwann cell nuclei in the electron micrographs.

The results of this study showed that, in the situations that immediate nerve repair using surgery is not possible, methylprednisolone administration preserves the axonal regenerative capacity of the distal segment of the transected nerve.

Light pollution causes structural and functional changes of many organs, especially those with cyclic activity. Research on the effects of artificial light and light pollution on the sexual cycle and fertility of females is limited. In this study, the effects of light pollution on the sexual cycle and the structural-hormonal characteristics of the thyroid and adrenal glands of female rats are investigated.

Twenty one female rats with regular sexual cycle were divided into three groups as control (12 h light/12 h dark cycle), experimental 1 (16 h light/8 h dark cycle) and experimental 2 (20 h light/4 h dark cycle). Animals were exposed to light for 47 days and vaginal smear was examined daily. Then, the animals were mated with male rats. Pregnancy was confirmed by observing the vaginal plaque of pregnancy. The pregnant animals were kept in the light/dark cycle conditions until the 19th day of pregnancy. On the 19th day of pregnancy, rats were bled under deep anesthesia and serum levels of T4, thyroid stimulating hormone and cortisol were measured. Then, thyroid and adrenal glands were dissected out and morphologically examined.

In experimental groups 1 and 2, the sexual cycle became irregular and remained in the estrus stage in almost all rats. Compared with the control group, size of thyroid follicles decreased and the mean level of T4 hormone increased significantly (p < 0.05) in the experimental groups. Serum levels of thyroid-stimulating hormone and cortisol did not change, but the thickness of the fascicle area in the adrenal gland increased significantly (p < 0.05). 

The thyroid and adrenal glands of rats are sensitive to light pollution and their function is altered.‎

The retrograde neuronal death in the dorsal root ganglia (DRG) can be the main factor in poor regeneration of injured peripheral nerves occurring by increased activity of oxidant agents. The present study investigated the effect of thiamine treatment, as an antioxidant, on neuronal death after sciatic nerve transection.

Twenty-five male Wistar rats were allocated in 5 experimental groups (n = 5). Group 1 was considered as intact. The sciatic nerve was transected in groups 2 to 5. Then rats were treated daily with physiological saline (control group), thiamine (50 and 100 mg/kg; i.p.) and thiamine (1.7 mg/kg locally). After four weeks, animals were sacrificed and L5DRG was removed for histological assessment.

Morphological analysis showed some no cell areas in L5DRG sections, which may be related to apoptotic cells in axotomized animals. L5DRG volume measurement showed no significant difference between intact and local thiamine treated group, while its volume was significantly reduced in other experimental groups (p < 0.001). This parameter was also significantly reduced in control group compared with local thiamine treated group (p < 0.001). Although the difference of L5DRG cell number in local thiamine treated group was not significant, its reduction was significant in control and intraperitoneal groups compared with intact group (p < 0.01). The L5DRG cell count in local thiamine treated group was significantly higher than that in control group (p < 0.01).

These findings may indicate that thiamine if is administered in sufficient doses can be classified as neuroprotective agent.

Regeneration of nerve fibers in transected nerve injuries requires formation of growth cone and axonal sprouting, proliferation of Schwan cells, myelin synthesis and etc. Pharmacological interventions are recommended to improve and promote these processes. In the present study the effects of thiamine, dexamethasone and N-acetyl cysteine administrations on axonal sprouting are examined.

After transection of right sciatic nerve of 24 male Wistar rats, the two ends of cut nerve were sutured into a piece of silicone tube. The rats were then divided into four groups (n = 6); receiving N-acetyl cysteine (150 mg/kg), dexamethasone (0.2 mg/kg), thiamine (50 mg/kg) and normal saline (control) once daily by intraperitoneal injection. At the end of treatment period (16 weeks) animals were sacrificed and the axonal sprouts removed and histologically examined.

There was no significant difference in the number of nerve fibers, axonal diameter and myelin sheath thickness among experimental groups. However, axonal diameter was almost increased in thiamine treated group (p=0.06). Moreover, a significant decrease (p < 0.05) in nerve cross sectional area was observed in dexamethasone group. The axonal diameter and myelin sheath thickness were also significantly decreased (p < 0.05) in dexamethasone group, compare to thiamine group.

Our data indicate that sciatic nerve regeneration in rats is inhibited by dexamethasone, might be ameliorated by thiamine, and is not changed by N-acetyl cysteine.

Neuropathy as a common complication of diabetes might be induced by changes in the extracellular matrix, including the thickening of the basal membrane of the peripheral nerve and elevation of the advanced glycation end products in the extracellular matrix. Benfotiamine inhibits nerve damages induced by hyperglycemia through several pathways. The purpose of this study was to study the effect of Benfotiamine administration on the tensile strength of the sciatic nerve and its acellular scaffold in diabetic rat model.

Sixty rats were divided into control, sham and 4 and 8 weeks diabetic groups (with and/or without benfotiamine oral treatment; 100 mg /kg). Diabetes was induced by intraperitoneal injection of streptozotocin. At the end of the experimental periods (4 and 8 weeks) 1 cm segment of the middle part of the sciatic nerve was removed, half of it was decellularized by the Sandal method and then subjected to tensile strength test. Thin and semi-thin sections were also prepared for histological examinations.

The mean force for the breaking of nerve segment in the diabetic groups was significantly reduced compared to control group. Also, the length increase up to the breaking point in diabetic groups was significantly shorter than control group. There were no significant differences in the length increase and maximum force in benfotiamine-treated diabetic groups compared to control group

Alteration of extracellular matrix in diabetes condition, might affect the structure of the collagen fibers and therefore reduce the strength of the nerve against the stretch.

Iron is an essential and potentially toxic metal in the mammalian body. In the present study, the effects of Ferrous Sulphate as an exogenous iron on the neuronal degeneration induced by unilateral sciatic nerve transection (SNT) in L4 dorsal root ganglion (L4-DRG) have been investigated in rats. Twenty-four male Wistar rat were divided into 4 groups (n=6); control (intact), SNT+ Salin, SNT+ iron (5.6 mg/kg; i.p), and sham. Treatment was started 1 hour after injury and continued for 7 days following the injury. The L4-DRG were dissected out, fixed (formalin 10%) and then processed for paraffin embedding 3 weeks after injury. Serial sections of L4-DRGs were prepared, stained (H&E and Toluidine blue) and examined microscopically. The mean volume of L4-DRG was estimated using Cavalieri principle and neuron count was done by a stereological approach (Disector method). The mean number of neurons in SNT and SNT+ iron groups were significantly decreased compared to the control group. In addition, the mean DRG volume in SNT+iron group was significantly lower than control group. Treatment with iron seems to exacerbate the neuronal death induced by SNT in rats.

Exposure to estrogen like chemicals during critical periods of development particularly in the neonatal period can disrupt normal patterns of mammary tissue development later in life. In this study, the effects of neonatal exposure of tamoxifen anti-estrogen and zearalenone mycoestrogen on some histological characteristics of mammary gland in female mouse were investigated.
Twenty newborn female mice of BALB/c strain were divided into four groups: three experimental and one control group (with no treatment). Treatment groups included Tamoxifen (400 μg /kg /day) group, Zearalenone treatment group (2 mg /kg /day) and group treated with tamoxifen췦꭪垧ꉷ treatment group. Daily treatments were started on the first day of life and continued up to 5 subcutaneously. Then about 70 days after birth, mice were deeply anesthetized and the mammary tissue was removed from the body. Following histochemical staining, the samples were studied using light and transmission electron microcopies.
Findings: The result showed that epithelial thickness of milk duct and volume of the nipple in tamoxifen treatment group significantly (pDiscusion & The results of this study show that neonatal administration of tamoxifen probably exerts anti-estrogenic effects and it prevents the normal development of mammary tissue, but zearalenone do not have adverse consequences on mammary tissue.

Extracellular matrix (ECM) functions as a scaffold for tissue morphogenesis and regeneration, promotes the maintenance of differentiated tissue and plays an extremely indispensable role in cell proliferation and differentiation. As a corollary of this importance, studying the cell behaviors without considering the ECM is to some extent impossible. Deletion of cells from ECM obtains natural three dimensional matrices that ape the in vivo functions of ECM..
The current study aimed to verify whether acellular dermal matrix (ADM) is a suitable 3D-matrix for blastema tissue cells originated from pinna of rabbit and study different behaviors of these cells on ADM..
To prepare ADM, small pieces of skin were decellularized by repeated snap freeze-thaw and treatment with sodium dodecyl sulfate as a detergent. Decellularization was verified and proved by histological tests. Blastema rings were prepared by double punching the pinnas of male New Zealand White rabbits and cultured in vitro after assembling with ADM. Specimens were studied after 5, 10, 15, 20 and 25 days of culturing..
Migration of cells started on the fifth day. As a result of this migration, most cells were located on the surface of the scaffold and formed epiderm-like structure and some penetrated into the scaffold. By day 25, cells which had penetrated into the scaffold had various destinies such as becoming elongated spindle-shaped cells and creating blood vessel-like structures..
ADM can induce migration and probably differentiation of blastema tissue cells; therefore, it is a suitable 3D-model to study cell behaviors in vitro..

In this study the cranial nerves development of H. huso are explained from 1 to 54-days-old (1, 3, 6, 15, 21 and 54 days). Despite all the researches on fish brain, there are no study on nerves evolution on H. huso during their larvae life. For this research 40 samples of larvae H. husowere obtained (from each age, about six samples were selected). The specimens were maintained in fiberglass tank, then histological samples were taken from tissues and stained with hematoxylin and eosin for general histological studies using light microscope. According to the results, on 1 and 3-days-old, no nerve was observed. The terminal nerve and their dendrites were observed around the nasal cavity and the axons projected to different areas in forebrain especially around olfactory bulb diffusely, on 6-day-old fish. Also, olfactory, optic, oculomotor, trochlear, trigeminal, lateral line and vagus nerves were detected on 6-day-old fish, however two parts of lateral line nerve were separated on 54-day-old. Three nerves, profundus, facial and octaval were observed on 54-day-old, however, up to this age, epiphysial nerve was not observed.

In the field of human breast cancer, the most recent researches referred to the influence of endogenous estrogen or exposure to environmental estrogen, as risk factors. Zearalenone (ZEN) as a mycotoxin and its derivative α- zearalenol (α-ZOL) are known nonsteroidal estrogenic compounds with potential endocrine disrupting properties. The present study was designed to investigate the effects of ZEN and α-ZOL on human breast cancer cell lines MCF-7 and MDAMB-468. Cell lines were treated by low and high doses of ZEN and α-ZOL (0, 1, 30, 62, 125, 250 and 500 ng/ml and 1, 2, 4, 8, 15, 30, 62 and 125 µg/ml) for 24 and 48 hours. Then MTT colorimetric assay was used to evaluate the cytotoxicity effect of ZEN and α-ZOL. Furthermore, morphological changes of treated and untreated cell lines were studied under an inverted microscope. The results obtained from the present study demonstrated that both ZEN and α-ZOL enhance the cell viability of MCF-7 especially at low doses (1 - 500 ng/ml) and at a high dose of 125µg/ml after 24 and 48 hours. However, this effect for α-ZOL was somewhat greater than that for ZEN. On the other hand, these estrogenic compounds did not have any effect on the cell viability of MDA-MB-468. No morphological change was observed in treated cells. These results show that ZEN and α-ZOL enhance the rate of cell division in ER positive cells and therefore, exposure to this mycotoxin may increase the risk of breast cancer.

Frog skin secretions have potentials against a wide spectrum of bacteria. Also, frog skin compositions have healing properties. The aim of this study was to investigate the antibacterial potentials along with healing properties of frog skin Rana ridibunda, a species which thoroughly lives in Iran marshes, as a biological dressing on wounds. In this study, excisional wounds, dressed with frog skin, were compared between experimental and control groups of guinea pigs. In the experimental groups, wounds were dressed with the dermal (FS) and epidermal (RFS) sides of fresh frog R. ridibunda skin, while only usual cotton gauze covered the wounds of the control group. Furthermore, microbial samples were taken on different days (0, 3, 5, and 7 days post injury) to count the number of the colony-forming units. Additionally, the microbial penetration test was performed on frog skin and then the progression of wound closure was evaluated. In the microbial studies, the bacterial load considerably declined in the wounds treated with FS and RFS compared with the control wounds. On day 7 post injury, the numbers of the colony-forming units for the FS, RFS, and control groups were 6.75, 105, and 375, respectively. In the penetration test, fresh frog skin showed to be a bacterial resistant dressing. The results revealed that the rate of wound closure in the experimental groups significantly was accelerated in comparison with that in the control group. Our results demonstrated the antimicrobial properties of frog skin as a wound dressing, which has antimicrobial effects per se. This biological dressing shows promise as an effective biological wound dressing insofar as not only is it capable of resisting microbes and accelerating wound healing but also it is cost-effective and easy to use..

Uncoupling protein 2 (UCP2) in the inner mitochondrial membrane changes the activity of KATP channels and the cell excitability, probably by decreasing the ATP production. Given the expression of UCP2 in primary afferent neurons, and the importance of these channels in morphine-induced analgesia, genipin, an UCP2 inhibitor, may affect these processes, when administrated intrathecally. Tail flick assay and formalin test were used to study thermal and chemical pain, respectively, in adult male Wistar rats. Catheterization of the spinal subarachnoid space was used to localize the effects of genipin. Genipin increased pain sensation in tail flick assay and in the first phase of the formalin test, but decreased pain in the second phase of the formalin test (P<0.001 in all groups). Genipin also antagonized analgesic effect of morphine (P<0.01 in tail flick and P<0.001 in the first phase of the formalin test) and did potentiate it in the second phase of the formalin test (P<0.001); but had no effect on hyperalgesic effects of ultra-low dose of morphine. Probably, genipin increases ATP/ADP ratio, thereby inhibits KATP channels in primary pain afferents and lowers pain threshold and decreases analgesic effects of morphine, at least in part, by inhibition of UCP2. Apparently, the anti-inflammatory effect of genipin causes analgesia in the formalin test. Genipin had no effect on hyperalgesic effects of ultra-low dose of morphine, maybe due to the common signaling mechanisms such as KATP channels.

Anxiety symptoms have been reported to be present in many patients with diabetes mellitus. However, little is known about the effects of hyperglycemia in critical periods of the central nervous system development. We assessed locomotive, exploratory, and anxiety behaviors in adult rats that remained from infantile repeated hyperglycemia by the open field and elevated plus maze tests. Our findings showed significant hypo activity, reduced locomotive/exploratory activities, increased fear related behaviors, and anxiety state between hyperglycemic and control adult males and the same differences were observed among females. In addition, no significant behavioral alterations between male and female animals were observed. This study determined that repeated increments in daily blood sugar levels in newborns may affect neuronal functions and provide behavioral abnormalities in adults.

Since long lasting administration of anti-seizure drugs produces undesirable side effects, many efforts have been made during recent decades to find and replace the chemical drugs by medicinal plants. The aim of present study was to study the antiepileptic (anti-seizure) effects of hydroalcoholic extract of Melissa officinalis on experimental epileptiform seizures, induced by pentylenetetrazol (PTZ) in Wistar rat. After normalization, rats in experimental groups 1, 2 and 3 were injected (i.p) 50, 80 and 120 mg/kg hydroalcoholic extract of Melissa officinalis, respectively. Control animals were injected extract solvent as the same manner. After 30 minutes all rats were injected (i.p) 80 mg/kg PTZ and then examined for epileptiform behaviors for the next 60 minutes. The rate of mortality during the next 24 hour was also recorded. In comparison with control group, in all experimental groups the latent period of tonic-clonic generalized seizure was significantly (P<0.05) increased. Moreover, the mortality rate was decreased from 90% in control group to 30, 50 and 60% in experimental groups 1, 2 and 3, respectively. It can be concluded that hydroalcoholic extract of Melissa officinalis has potential sedative and anticonvulsant effects and probably exerts its effects through GABAergic system.

Launaea acanthodes is used as a common medicinal plant in central regions of Iran. To investigate the probable hypoglycemic activity of hydro-alcoholic extract of L. acanthodes as well as its effects on serum level of insulin and biochemical factors in normal and hyperglycemic rats, the present study was carried out. In this experimental study 24 male albino Wistar rats, weighting 250-300 g were randomly allocated into four groups (n=6); control, type 1 diabetic rats (STZ; 55 mg/kg), type 1 diabetic rats treated by subcutaneous injection of 5 IU/kg insulin (STZ+insulin) and type 1 diabetic rats treated by injection (i.p) of 150 mg/kg hydro-alcoholic extract of L. Acanthodes (STZ+extract). The injection of insulin and extract were done every day from day 1 to day 21 of experiment. After that, all animals were kept up to day 30. Blood serum were collected and analyzed for the levels of glucose and biochemical factors (cholesterol, triglyceride, LDL and HDL) measurements, in the 15th and 30th day of experiment. The results showed significant decrease (p<0.001) in glucose level and significant increase (p<0.05) in insulin level in STZ+extract group, when compared with other hyperglycemic groups in 30th day of experiment. These results indicate that the hydro- alcoholic extract of L.acanthodes could be effective in the treatment of diabetes. It can be concluded that extract administration somehow induce insulin secretion probably through stimulation of remaining β cells or their hyperplasia in Langerhans islets. This effect can also be referred to flavonoides constituent and antioxidant property of extract, too.

Oxidative stress is one of the probable molecular mechanisms involved in lead (Pb) neurotoxicity. On the other hand, lemon balm (Melissa officinalis) which is widely used in traditional medicine, has a high antioxidant activity. In this study, the protective impacts of Melissa officinalis on the adverse effects of Pb toxicity on learning ability were investigated. In this experimental-clinical trial, 40 virgin Wistar rats were mated and divided into control, control positive (vitamin C+Pb), control negative (Pb), and 3 Pb and Mellisa experimental groups. Mellisa was orally administered in three doses including + 25, 50 and 100 mg/ kg of body weight daily. Treatment started from 7th day of gestation and continued through pregnancy and lactation periods. The three month- old offsprings in each group were assessed in terms of memory and learning ability by Morris water maze test and the results were compared between the groups. Exposure to Pb during and after gestation leads to learning disorders. While concomitant administration of Pb and Melissa, as well as vitamin C can, to a large degree, reduce the adverse effects of Pb on learning abilities. Since no significant differences were obtained from the comparison of results in the control, Pb+M and vitamin C+Pb groups, it can be concluded that Melissa has antioxidant impacts equal to vitamin C. Therefore, similar to vitamin C, Mellisa can decrease the neurotoxic effects of Pb.

Equisetum telmateia (Equisetaceae) seems to have anti inflammatory and antioxidant properties. In the present study, the neuroprotective effects of organic and inorganic silica were investigated on spinal cord alpha motoneuron of rats after injury of sciatic nerve. After highly compression of sciatic nerve in 42 Wistar rats, the injured rats were divided into sham (n= 6) and two experimental groups which each were divided into 3 subgroups (n= 6). The first subgroups received 3, 6 or 9 injections (15 mg/kg/injection, ip) of horse tail extract and the second subgroups received 3, 6 or 9 injections (6 mg/kg/injection, ip) of sodium meta silicate, respectively. The first injection was made after sciatic nerve injury and the others by 72 hours intervals. After a month, the rats were sacrificed and their spinal cord lumber segment sampled, processed for histological preparation and analyzed stereologicaly (the dissector technique) for estimation of numerical density of alpha motoneurons. The results showed significant decrease in the numerical density of alpha motoneurons in shams (p< 0.05) and no significant differences between experimental and control groups. This may suggest the neuroprotective effects of silica on the survival of alpha motoneurons.