Physiology and Pharmacology
Volume:18 Issue: 1, 2014

Free radical can be defined as a molecule or molecular fragments containing unpaired electron in the outer orbital، which react with nearby molecules to get stability. There are two types of them in the body: oxygen free radicals and nitrogen free radicals. Our body has an antioxidant defense system which prevents accumulation of these radicals. There is a balance between free radical production and antioxidant defense system. Excessive free radical production or weak antioxidant system leads to oxidative or nitrosative stress. Diabetes mellitus is one of most important diseases that show cell injury due to oxidative and nitrosative stress in many tissues especially arteries. It causes atherosclerotic plaques in arteries by induction of inflammation، increasing the adhesive molecule expression، extravasation of circulating inflammatory cells، over-expression of some transcription factors، and fat deposition in the wall of arteries. Exercise is one of the main factors that influence production of free radicals and performance of antioxidant defense system. Although strenuous and acute exercise induces oxidative stress by increasing production of free radicals، but regular moderate exercise causes resistance against oxidative and nitrosative stress by potentiating antioxidant defense/repair systems. It appears that regular exercise accompanied by changes in life style is effective in reducing complications of diabetes، especially in prevention of atherosclerosis.

Leukemia is considered one of the main causes of death، and current chemotherapeutic agents are unable to provide optimal responses due to chemo-resistance. Therefore، there is a constant need for new drugs. Cyclooxygenase- 2 (COX-2) inhibitors can be helpful by reducing the necessary dose of routine chemotherapeutic drugs. Herein، we evaluated the cytotoxicity activity as well as the morphological changes induced by compounds A (3-(4- chlorophenyl) -5- (4-flurophenyl) -4-Phenyl-4،5-dihydro-1،2،4-oxadiazole) and B (3،5-bis(4 chlorophenyl) -4-Phenyl-4،5- dihydro-1،2،4-oxadiazole) as COX-2 inhibitors. In addition، the upstream mechanism was investigated by measuring expression of nuclear factor kappa light-chain-enhancer of activated B cells (NF-κB) and ferritin heavy chain (FHC). K562 leukemia cell line was cultured، treated with the above-mentioned two compounds، and their IC50 values obtained. Compounds A and B-treated cells were analyzed for morphologic changes by fluorescence microscope after 16 h incubation at their IC50 concentrations. The protein fraction of whole cell lysate was prepared to evaluate NF- κB by NF-κB assay kit. FHC expression was also determined using western blotting. Treatment of cells with the compounds A and B resulted in considerable apoptotic morphological changes according to DAPI staining. NF-κB assay demonstrated its significant decrease due to compound B. Our experiment also revealed a significant reduction in FHC expression after treatment with compound B. Compound B can induce cytotoxicity and morphological changes in leukemic cell line probably through NF-κB/FHC pathway.

TRPV1 is a non-selective cation channel with high permeability to calcium ions، and is also involved in the development of neurogenic and inflammatory pain. The increase in intracellular calcium plays a role in worsening of stroke. In the present study we investigated the effect of (AMG9810) TRPV1 receptor antagonist on stroke outcome in the permanent middle cerebral artery occlusion model in rat. In this experimental study، a total of 24 male Wistar rats weighing 250-300g were divided into 3 groups as following: control، treatment and sham. Stroke was induced by permanent middle cerebral artery occlusion method. The animals were then treated with the TRPV1 receptor antagonist Amg9810 (0. 5 mg/kg، ip) and vehicle (DMSO) 3h after stroke. Infarct volume was determined by TTC stai ing، and sensory motor deficits were assessed by sticky and hanging tests at 1، 3 and 7 days after stroke induction، and compared. One week after stroke، Amg9810 decreased the cortical infarct volume (P 0. 05). The touch time and remove time (in sticky test) was decreased in these animals (P<0. 001) but hanging test was increased (P<0. 01). TRPV1 receptor inhibition may decrease infarct volume and sensory-motor deficits following stroke due to permanent middle cerebral artery occlusion in rat.

Stimulation or inactivation of the lateral hypothalamus (LH) produces antinociception. Studies showed a role for the ventral tegmental area (VTA) in the antinociception induced by LH chemical stimulation through the orexinergic receptors. In this study، we assessed the role of intra-VTA dopamine D1 and D2 receptors in antinociceptive effects of cholinergic agonist، carbachol، microinjected into the LH in the tail-flick test. Rats were unilaterally implanted with two separate cannulae into the VTA and LH. Intra-VTA infusions of selective D1 receptor antagonist SCH-23390 (0. 125، 0. 25، 1 and 4 μg/0. 3 μl saline) and selective D2 receptor antagonist sulpiride (0. 125، 0. 25، 1 and 4 μg/0. 3 μl DMSO) 2 min before microinjection of carbachol (125 nmol/rat; effective dose) into the LH was done. The antinociceptive effects of different doses of these antagonists were measured using a tail-flick analgesiometer، and represented as maximal possible effect (%MPE) at 5، 15، 30، 45 and 60 min after administration. The results showed that intra-VTA administration of D1 and D2 dopamine receptors antagonists could significantly prevent the development of LH stimulation-induced antinociception. Administration of maximum doses of SCH-23390 and Sulpiride (4 μg) didn’t affect the nociceptive behaviors in acute model of pain. Thus dopamine receptors in the VTA play a modulating role in carbachol induced analgesia within the LH، in acute model of pain. It is supposed that there is an interaction between VTA dopaminergic and orexinergic systems in pain modulation.

Varicocele is a pathological dilation of spermatic cord vein plexus، and celecoxib، an inhibitor of cyclo-oxygenase-2، is widely used in the treatment of chronic inflammation. So، we examined the effects of celecoxib on inflammatory cytokines، testicular Sertoli and spermatogonial cells number، seminiferous tubule diameter، and sperm indices in immature male rats with induced varicocele. Twenty four immature Wistar male rats (100-120 gr) were randomly assigned into four groups (sham، varicocele، celecoxib sham and celecoxib varicocele). The sham group underwent sham operation، and the varicocele group underwent partial ligation of the renal vein to induce experimental varicocele. In the celecoxib group 30 mg/kg celecoxib was administrated for 5 weeks (8-13 weeks) by gavage. Serum، testis and sperm samples were collected at the end of 13 weeks for evaluation of celecoxib effects. Histological evaluation of the testis was made by periodic acid Schiff staining. Levels of cytokines IL-6 and INF- γ in serum and testis were assessed by ELISA kits. Sperm indices، seminiferous tubule diameter، and cell counts were evaluated. Celecoxib caused a significant decrease in concentration of serum and testis inflammatory cytokines، compared to the varicocele group (P<0. 05). Celecoxib also significantly increased testicular cell numbers (Sertoli cells and spermatogonia)، seminiferous tubule diameter and sperm motility compared to the varicocele group (P<0. 05). Varicocele has a detrimental effect on fertility by increasing cytokines levels and decreasing cell numbers، seminiferous tubule diameter and sperm indices، and celecoxib may be beneficial for treatment of varicocele by improving varicocele side effects.

The brain glutamate system plays a central role in response to stress. This study examines the effect of memantine (a NMDA glutamate receptor antagonist) on stress from plantar electrical shock in male NMRI mice (Pasture Institute، Iran)، weighing 25-30 g (n=6/group). The nucleus accumbens was bilaterally cannulated in a group of animals، and seven days later، different doses of memantine (1 and 5 μg/mouse) was administered 5 min before inducing stress. In other groups، different doses of the drug (1 and 5 mg/kg) were administered to the animals intraperitoneally 30 min before the stress induction. Then food and water intake، anorexia، and the amount of urine and fecal materials were measured. The stress reduced food intake and increased water intake in the animals. In addition، anorexia، fecal weight and urine volume were increased dramatically in these animals. Intraperitoneal memantine injection increased food intake and decreased water intake. This occurred when the drug was administered intra-accumbally، too. Memantine inhibited stress-induced anorexia when administered either intraperitoneally or intra-accumbally. Memantine (both peripherally and centrally) also changed stress-induced fecal passage but decreased urination. Memantine administration can inhibit or potentiate stress effects، which may be at least partially integrated in the nucleus accumbens.

Since Curcuma longa extract and curcumin have been shown to be potent antioxidant agents، they were used in cultured adult mouse spinal cord slices to investigate whether they can inhibit apoptosis in motor neurons. Slices from the thoracic region of adult mice spinal cord were divided into four groups: 1. Freshlyprepared slices (time 0); 2. Control; 3. Slices treated by curcumin (20 μM); and 4. Slices treated by Curcuma longa extract (1000 ppm). The control and the treated slices were cultured for 6 hours. MTT 3- (4،5-dimethylthiazol-2-yl) -2،5- diphenyltetrazolium bromide] assay was used to evaluate slice viability in the four groups. Morphological and biochemical features of apoptosis were studied using fluorescent staining (propidium iodide and Hoechst 33342) and TUNEL method، respectively. Data were analyzed using one-way ANOVA. The viability of slices cultured for 6 hours (control) was considerably decreased compared to freshlyprepared slices. Motor neurons from slices cultured for 6 hours showed morphological and biochemical features of apoptosis. At this time point، the application of either curcumin or Curcuma longa extract not only increased the viability of cultured slices compared to the control، but also they could inhibit morphological and biochemical features of apoptosis in the motor neurons. Oxidative stress might be a possible mechanism for the induction of apoptosis of motor neurons in cultured spinal cord slices.

This study investigated the effect of berberine on renal dysfunction and histological damages of the lung induced by renal ischemia/ reperfusion at an early stage. There were four experimental groups of adult male rats (n=7). Seven days before induction of ischemia، the Ber+I/R group received oral (by gavage) berberine (15 mg/kg/day) while the I/R group received distilled water. Renal arteries were not occluded in the sham group and Ber+sham group، and they were administered distilled water and berberine (15 mg/kg/day)، respectively، by gavage 7 days before surgery. Renal ischemia was induced by occlusion of both renal arteries for 45 min followed by 24 h of reperfusion. Blood samples were collected for biochemical analysis، and finally lung samples were preserved for light microscopical examination. The 45 min ischemia/24 h reperfusion resulted in renal functional disorders and histological damages to the lung، which were associated with increased plasma levels of creatinine، blood urea nitrogen (BUN)، lactate dehydrogenase (LDH) and alkaline phosphatase (ALK) during reperfusion period. In the Ber+I/R group، renal functional disorders and histological damage to the lung were improved، which was accompanied by less increase in plasma creatinine، BUN، LDH and ALK than those of the non-treated rats. Berberine has an ameliorative effect on renal as well as pulmonary injuries following renal ischemia/reperfusion in rats.

Several factors such as diseases، medications and humoral agents can delay or speed up wound healing process. Because of the limited information about the hormonal changes during wound healing، in this study the relationship between serum levels of growth hormone، insulin and cortisol with wound healing in normal and diabetic rats was evaluated. Male Wistar rats)weighing 250 ± 20 g (were divided into three groups: control، normal (non-diabetic) and diabetic (induced by streptozotocin). The wound size made on the back of normal and diabetic rats was measured at days 0، 7، 14 and 21، and the serum levels of growth hormone، insulin and cortisol were measured. The speed of wound healing in normal rats was higher than diabetic rats. Serum insulin concentrations were less in the diabetic rats in comparison with the normal and control groups (p<0. 00، and showed correlation with wound healing process in diabetic rats (p<0. 01). Serum cortisol concentrations decreased in normal and diabetic groups during wound healing (p<0. 001) but did not show significant correlation with this process. Serum growth hormone levels did not significantly change in any of the groups، and did not show significant correlation with wound healing process، too. Reduction of serum insulin level is probably responsible for delayed wound healing in diabetes، and intrinsic mechanisms facilitate wound healing in normal and diabetic conditions by reducing the release of cortisol.

Arterial hypertension is one of the causes of stroke، and as one of the vasculotoxic conditions intensifies ischemic stroke complications. The aim of the present study was to analyze the effects of short-term cerebral hypertension on ischemia/reperfusion injury and pathogenesis of ischemic stroke. The experiments were performed on three groups of rats (N=36); Sham، control ischemia and hypertensive ischemia. Rats were made acutely hypertensive by abdominal aortic coarctation، and after 8 days، were randomly selected for cerebral ischemia induced by middle cerebral artery occlusion (MCAO) for 60 min followed by 12 h reperfusion. The rats were slaughtered under deep anesthesia for measurement of cerebral injury area by triphenyltetrazolium chloride staining method or blood-brain barrier (BBB) integrity disruption by Evans blue extravasation technique. Arterial pressure was increased >36% in hypertensive rats، and blood flow of the ischemic region was reduced by 80% in the ischemic groups compared with the sham. MCAO induced infarction in large areas of the right hemisphere in hypertensive rats compared with control ischemic rats، and subcortical infarct volume was significantly more in ischemic groups (236±43 vs. 139±25 mm3). MCAO also increased Evans blue extravasations in hypertensive rats (9. 48±2. 03 μg/g) more than non-hypertensive rats (5. 09±1. 41 μg/g). The findings of present study indicate that the short-term hypertension intensifies the ischemia/reperfusion-induced brain injuries. This type of hypertension also causes severe damage in BBB function and enhanced cerebrovascular permeability after brain ischemia.