مجله سلول و بافت
سال یکم شماره 1 (پاییز 1389)

The aim of this study was to investigate the inhibitory effect of calcium chelators on apoptosis of motor neurons in adult spinal cord slices. The thoracic region of adult mouse spinal cord was sliced by a tissue chopper into 400 µm sections and divided into four groups: 1- freshly dissected slices (0 hour), 2- control slices, 3- slices treated by ethylene deamin tetra acetic acid (EDTA) and 4- slices treated by ethylene glycol tetra acetic acid (EGTA). The control and treated slices were incubated in a culture medium for 6 hours. MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide] assay was used to evaluate the viability of the slices. To study motor neurons morphology, propidium iodide and Hoechst 33342 were used. Data were analyzed using one- way ANOVA and Tukey test, and means difference was considered significant at p<0.05. Motor neurons from slices cultured for 6 hours displayed morphological features of apoptosis. The application of calcium chelators (EDTA and EGTA) not only increased the viability of the cultured slices, but also inhibited apoptosis in the motor neurons and increased the percentage of viable motor neurons. It could be concluded that apoptosis in motor neurons of cultured spinal cord slices might be due to increased level of intracellular calcium.

Utilizing Aspergillus polluted feed causes aflatoxin production, disturbing disordered domestic health, milk and consumers cycle. In this research the relationship of milk aflatoxin M1 and feed fungi flora was studied in Markazi Province. In this study the feed composition used in ten grazieries in Markazi Province in years 2009 and 2010 were examined. Isolation, cultivation and identification of feed fungi were done. Also the resulting produced milk aflatoxin M1 was measured using ELISA method.Then the relationship between feed composition, molds and milk aflatoxin were calculated. Results showed that the most feed composition were zea, cotton and kolza cakes, feed complementary, barley, wheat bran, dried bread, fat powder and alfalfa. The most comon feed pollutants were Aspergillus flavus, A. clavatus and Rhizopus stolonifere. Anuall studies on collected milk from grazieries showed existing aflatoxin M1 in all of them. Statistical analysis of data confirmed a strong correlation between soya and kolsa cakes with Aspergillus molds in feed and milk pollution to aflatoxin. Control al feed mold pollution is the best method for the prevention of milk and its products bing polluted to aflatoxins that helps to improve community health.

Movement of water across cellular membranes is facilitated by the presence of water channels named aquaporins (AQPs). Mercurial compounds are potent blockers of plant and animal aquaporins. However some aquaporin isoforms such as NtAQP1 in tobacco are mercury-insensitive. The aim of this research was to determine the sensitivity of tobacco NtPIP2;1 to mercury. In this experimental study, after invitro transcription of NtPIP2;1 and cRNA synthesis, cRNA was injected to Xenopus oocytes by microinjection. Two days after incubation, oocytes were subjected to 1 mM mercury chloride for 10 min. Then, oocyte volume swelling assay in hypotonic medium was conducted and the membrane osmotic water permeability coefficient (Pf) was determined. Pf for control and mercury chloride-treated oocytes expressing NtPIP2;1 was respectively calculated 0.99×10-2 and 0.98×10-2 cm s-1, which was not significant (P>0.05). Comparing the amino acid sequence of NtPIP2;1 with NtAQP1, a mercury-insensitive aquaporin, revealed the similar to NtAQP1 replacement of cys with Thr in 233 position near the aquaporin pore in NtPIP2;1. NtPIP2;1 encodes a mercury-insensitive aquaporin in tobacco which could be due to cysteine replacement with threonin near the aquaporin pore.

The effects of mobile phones waves investigated on rat ovary. 28 rats with weight of 200±20g and age of 80-90 days selected and divided into four groups including control, sham, exposed number 1 and 2. For two weeks and one month, experimental 1 and 2 groups were exposed to mobile calls 12 times a day and each time for 10 minutes. The sham group was exposed to non-calling switched-on mobile phones. The concentration of hormones measured using ELISA method. The number of follicles calculated with physical dissector technique. The results showed no significant difference in the ovarian weight and number of primary follicles and corpus luteum. In different groups the number of secondary follicles decreased significantly in the exposed and sham groups compared to the control group. The number of Graffian follicles decreased significantly in the exposed group number1and sham in comparison to the control group while the number of atretic follicles increased significantly in both exposed groups in compared to the control and sham groups. The level of LH increased significantly in exposed group number1 in compared to the control group while the level of FSH increased significantly in the exposed group number 2 when compared to the control and sham groups. The level of estrogen and progesterone increased significantly in the exposed groups in compared to the control and sham groups. The mobile phone waves may increase ovarian follicles atresia, disrupt the regulation of hormonal secretion and affect the fertility rate.

Electromagnetic field (EMF) is an unavoidable environmental factor for living beings which many investigations have been conducted to evaluate its effect. In this research the effects of EMF on vegetative organs, pollen development, pollen germination and pollen tube growth of Glycine max L. were studied. Exposure to EMF was performed by a locally designed generator which its electrical power was provided by a 220 V and 0.1 A, AC power supply. This system consist of a PVC cylinder with 20 × 20 cm (diameter and length) and 300 turn coil of copper wire. The structure of vegetative parts and reproductive organs was studied using common methods of cell – histology. In the stem of treated samples collenchymas layers were increased and formation of xylem tissues was more rapid. In the leaves, spongy parenchyma tissue was deformed and numbers of trichomes were increased, in addition leaves and shoot development were delayed and the size of anthers was also decreased with the deformation of their cell wall. The numbers of pollen and tetraspore, decreased and they were also abnormal in shape. Under EMF treatment, the germination percentage of pollen was decreased and pollen tubes were helicoidal and short. Low intensity electromagnetic field may have effects on the structure of some organs and developmental characteristic of them in Glycine max L.

Recently, the use of decellularized tissue as a natural scaffold has been considered in tissue engineering. The purpose of this study was to prepare a natural scaffold by decellularization of sciatic nerve and investigate the viability of seeded rat bone marrow Mesenchymal stem cells on that. In this experimental study, the rat sciatic nerve was decellularized using three detergents namely Triton X-100, Sodium dodecyl sulfate and sodium desoxy cholate, then rat bone marrow mesenchymal stem cells were seeded on the scaffold by centrifugation method in DMEM medium (Dulbecco Modified Eagle Medium) containing 15% FBS (Fetal Bovine Serum). The viability of cells was evaluated using MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium-bromide) test on days 1, 5, 10, 15 and 20. The morphology of the decellulized sciatic nerve and the cells seeded on that were studied using hematoxilin and eosin (H&E) and acridin orange. The data was analyzed using one-way ANOVA and Tukey test and the means difference was considered significant at P<0.05. Histological studies showed complete removal of the cells from detergent-treated sciatic nerve. The number of viable cells on the scaffold showed a significant increase (P<0.05) 20 days after seeding compared to day 1 and 5, however, the number of viable cells did not increase significantly during days 10, 15 and 20. The results of this study showed that the prepared scaffold provided a suitable environment for the seeding, growth and proliferation of rat bone marrow mesenchymal stem cells.

Extracellular matrix (ECM), in addition to physical role can control the cellular behavior such as proliferation, differentiation and migration. With respect to dimension, architecture, cell polarity and microenvironment similar to in vivo, it is important to study cellular behavior in the three dimensional culture compare to two dimensions. In this study, ECM derived from bovine articular cartilage and cancellous bone were used as a three dimensional environments to study the movement and polarity of cells from blastema tissues. In order to remove cells from the cancellous bone and articular cartilage, physicochemical methods including snap freeze–thaw and sodium dodecyl sulfate (SDS) as an ionic detergent were used. Then the prepared decellulized matrix were assembled with the rings of the blastema tissues originated from pinnas of male New Zealand white rabbits and cultured in different days in vitro. The removals of the cells have been confirmed by histotechniques. In addition adhesion, polarity and migration of the blastema cells around the trabeculae of bone and articular cartilage ECM took place. This study showed that the co-culture of blastema tissue with dynamic cells and 3D scaffolds might be a suitable model to study cell behavior such as migration and polarity in vitro.

The aim was to investigate the interactions and cellular behavior of the blastema tissue and natural 3D elastic scaffold in vitro. In this study cows aorta was used as a scaffold. To prepare a very porous elastic scaffold, the cells and collagen were removed by treating that with 50 mg/ml cyanogen bromide in 70% formic acid. The prepared scaffold were then placed inside the blastmea rings and kept in culture media for 40 days. The interaction between blastema tissues and elastic scaffolds were studied in 10 days intervals. Microscopic studies in different day on blastema tissue and scaffold revealed that the cells and collagen fibers were omitted successfully from the elastic scaffold. Moreover, histological studies indicated that the cells had penetrated into the scaffold. In addition cell devision, probable differentiation of blastema cells to fibroblast and myocyte and also angiogenesis due to inductve effect of elastic scaffold were abserved. Our results indicated that, it is possible to prepare a natural elastic scaffold from aorta by treatment with cyanogen bromide. On the other hand, this scaffold may have inductive effects on cell behaviors such as migration, adhesion, cell division and probably differentiation. Further studies are required to confirm the indentity of cells and other properties of the scaffold and also its possible use in engineering of vascular tissue.