Morphological changes of the hippocampal astrocytes at different phases of the estrous cycle in female mice

Usual fluctuations of sex hormones during the estrous cycle in female miceaffect the hippocampal neurogenesis. The hippocampus also comprises many steroidreceptors suggesting the modulatory effects of gonadal hormones on the hippocampalplasticity. Sex differences at the level of structure and function of the hippocampus aremostly due to the fluctuations of steroid hormones during the estrous cycle. The purpose ofthis study was to investigate the morphological changes in hippocampal astrocytes and alsothe expression of glial fibrillary acidic protein [GFAP] at different phases of the estrouscycle. In this study, different stages of the estrous cycle were determinedin 6-8 week NMRI female mice by methylene blue-stained vaginal smears. Themorphological changes of astrocytes in the hippocampus were investigated using GFAPimmunohistochemistry. In addition to the morphological study, the expression of astrocyticmarker was quantitatively evaluated. GFAP immunostaining showed the changes in the morphology of astrocytes andalso in the serum level of estrogen during the estrous cycle. The highest concentrations ofestrogen and GFAP reactivity were observed in the proestrus stage. Different stages of the estrous cycle in female mice were associated withmorphological changes of hippocampal astrocytes and the alternation in the serum level ofestrogen

[ effect of intravenous transplantation of adipose-derived stem cells on hippocampal neurogenesis after 6-hydroxydopamine induced injury]

Released dopamine from dopaminergic neurons in the substantia nigra pars compacta affects dentate gyrus [DG] neurogenesis in the hippocampus [HPC]. Damage to dopaminergic neurons in Parkinson's disease [PD] causes decreased neurogenesis in DG which results in memory impairment. This was an experimental laboratory study. We assessed the effect of intravenous transplantation of adipose-derived stem cells [ADSCs] on hippocampal neurogenesis after inducing injury by 6-OHDA [memory disability model of PD].We performed bilateral injections of 6-OHDA into substantia nigra [SNc] of male Wistar rats. First group of the rats received bilateral injections of 6-OHDA [6 micro g] dissolved in 2 micro l saline. Second group received saline injections instead of neurotoxin [sham group]. In the third group we transplanted the 3[rd] passage of ADSC cells which had been assessed for CD90 immunostaining [1×10[6] in 500 microl medium], via tail vein. The 4[th] group included injured rats which received an injection of the fluid of the culture media [500 micro l] through tail vein. After treatment, rats were sacrificed. The brains of the rats were removed, fixed with 4% paraformaldehyde, dehydrated, embedded in paraffin and cut into 10 micro m thick slices. We stained the sections with cresyl violet and determined the density of neurons in DG, CA1, CA3. Statistical analysis was performed by one-way ANOVA and Tukey test. P

[Comparison of the proliferation potential and neurotrophic factors expression in the adherent neural stem cells culture of the subgranular, subventricular zone and the central canal of the spinal cord of the adult rats]

Degeneration of neurons in the central nervous system occurs during aging. Transplantation of neural stem cells [NSCs] can be preventing the degeneration of neurons. In addition to neuronal replacement, with the production of neurotrophic factors, increased survival and proliferation of endogenous cells. This study was done to compare the cell proliferation, neurotrophic factors expression and features of NSCs harvested from different areas of the central nervous system in vitro. In this laboratory study NSCs have been harvested from subgranular zone [SGZ], subventricular zone [SVZ] and central canal of spinal cord from adult Wistar rats with mechanical, enzymatical digestion and subsequently was cultured in alpha-MEM medium supplemented with serum as monolayer or adherent conditions and passaged for 13 times. Immunocytochemistry was used to determine expression of the nestin and GFAP markers. Semi-quantitative RT-PCR was used to confirm genes expression [NGF, CNTF, NT3, NT4/5, GDNF and BDNF]. Morphological features of stem cells extracted from different regions of the central nervous system were similar in the culture. Doubling time NSCs in the SVZ [37.45 hr] is shorter than in the SGZ [44.04 hr] and central canal of spinal cord [57.22 hr]. The culture conditions as well as monolayer neural stem cells are capable of producing neurospheres. Also, nestin and GFAP markers, expressed by NSCs. Neurotrophic gene expression pattern profiles were similar to each other in stem cells extracted from the SGZ, SVZ and central canal of spinal cord. Neurotrophic gene expression in stem cells extracted from different regions of the central nervous system were similar, but proliferation capacity was higher in NSCs, which have been harvested from the SVZ

Isolation and culture of interfollicular epidermal stem cells from newborn mouse skin without feeder layer

Epidermis is the outer layer of skin, regenerating continuously. Epidermal stem cells play important roles in tissue regeneration, scar regeneration and neoplasm formation.This study was displayed for the isolation and culture of interfollicular epidermal stem cells from newborn mouse skin without feeder layer. This experimental study was displayed on 0-3 old-day newborn NMRI mouse skin 60-70 gr weight. The epidermal keratinocytes were separated mechanically and enzymatically from 0-3 old day newborn mice skin [NMRI strain] and seeded on fibronectin-collagen culture substrates. Putative epidermal stem cells were selected by rapid adherence for 10 minutes on this composite matrix of type 1 collagen and fibronectin and the unattached cells were discarded and attached cells were cultured in essential minimal eagle medium [EMEM] [ca+2-free culture medium containing 0.05 mM Ca+2, 9% FBS, 50% conditioned medium, EGF [epidermal growth factor] and Cholera Toxin. The immunocytochemistry of beta1-integrin analysis used to indicate their stemness nature. The results indicated that rapid adherence yields 50% purity. By using this method, the stem cells have been subcultured continuously without any change in the cell properties. The isolated interfollicular epidermal stem cells, expressed epidermal stem cells special marker [beta1-integrin] in high levels, which indicates stem cell nature. This new method yields pure viable epidermal stem cells that can be used in regenerative medicine and cell therapy

[Inductive effect of deprenyl and dimethyl sulfoxide on proliferation and survival of the mesenchymal stem cells]

Research have been focused on the applying the chemical inducer for transdifferentiation the adult BMSCs into neural cell. So that, at the first should investigate the toxcity effect of the chemical inducer on the induced cells. Plasticity and easy accessibility of bone marrow mesenchymal stem cells is a unique charactristic for treatment of neural disorderies. This study was desgined to determine the inductive effect of Deprenyl and Dimethyl sulfoxide on proliferation and survival of the mesenchymal stem cells. In this experimental study, BMSCs isolated from the adult rat bone marrow and cultured in alpha MEM containing 10% FBS. Cell identity for surface antigens was performed in third passage by immunocytochemistry and multipotancy capacity of BMSCs was done by BMSC differentiation into adipocytes and osteocytes. The cells were exposed to chemical agents [a: the alpha MEM medium supplemented with 2% DMSO, b: the alpha MEM medium supplemented with 10[-8]M Deprenyl] for 24 hours and then transferred to alpha MEM containing 10% FBS cell survival and proliferation was evaluated after the 24, 48, 72 and 96 houres by MTT [3-[4-5-Dimethylthiazolyl-2-y1]-2,5-diphenyltetrazolium romid] test. Data were analyzed using SPSS-16, One-Way ANOVA and Tukey tests. In addition to expression the surface antigens and adipogenic and osteogenic differentiation by BMSCs, MTT test results showed that proliferation and survival of induced-deprenyl and DMSO cells within 48, 72 and 96 hours after the induction was increased significantly than negative control group. Deprenyl increases survival and cell proliferation compared to Dimethyl Sulfoxide. It can be used as cell inducer

[Assessment of neurotrophic factors expression and cell proliferation in the coculture of neural and mesenchymal stem cells]

Neurotrophic factors are diffusible polypeptides that have critical roles in survival, proliferation and differentiation of stem cells. This study was done to assess the role of neurotrophic factors [CNTF, BDNF, GDNF, NT-3] expression and proliferation rate of neural stem cells [NSCs] in coculture with mesenchymal stem cells [MSCs]. In this experimental study, NSCs and MSCs were isolated from adult Wistar rat. Initially, NSCs was harvested from temporal lobe after mechanical digestion by a sterile flamed Pasteur pipette and enzymatic digestion with trypsin and Dnase. The cell suspension was cultivated in a flask with DMEM/F12 medium supplemented with 10% FBS 100U/ml Penicillin and 100 mg/ml Streptomycin. To obtain MSCs, bone marrow of femur and tibia bones were flashed out and cultured. MSCs and NSCs cocultured by transwell system in DMEM/F12 medium supplemented with 10% FBS 100U/ml Penicillin and 100 mg/ml Streptomycin. Haemocytometer, immunocytochemistry and RT-PCR methods were performed to identify and evaluate cell proliferation, purity levels and neurotrophic factors expression. There is no differences in NTFs profile of neurotrophic factors expression between coculture group and control NSCs, but interactions between MSCs and NSCs significantly promoted NSCs proliferation [P<0.05]. This study showed that coculture of NSCs with MSCs might be prfered in cell-therapy than NSC

[Expression of nestin and nerve growth factors in adipose-derived mesenchymal stem cells]

Background: Adipose tissue represents an accessible source of mesenchymal stem cells [Adipose tissue derived mesenchymal stem cells-ADSCs]. ADSCs could be differentiated into various mesenchymal stem cells [e.g. chondrocytes, adipocytes, osteoblasts, and neuronal lineages]. Neurotrophic factors are diffusible polypeptides that have a critical role in survival, proliferation and differentiation of stem cells. This study aimed to evaluate the proliferative capacity and the expression of some neurotrophic factors such as brain-derived neurotrophic factor [BDNF], ciliary neurotrophic factor [CNTF], glial cell-derived neurotrophic factor [GDNF], neurotrophin-3 [NT-3], neurotrophin-4 [NT-4], nerve growth factor [NGF] and the expression of nestin in ADSCs

Materials and Methods: Rat ADSCs were isolated from the subcutaneous adipose tissue using mechanical and enzymatic digestion. These cells were cultured in alpha MEM supplemented with 10% fetal bovine serum. ADSCs of the third passage were evaluated by immunocytochemistry to detect the cell surface markers of CD90 and nestin. Reverse transcription-polymerase chain reaction [RT-PCR] was used to study the expression of the above-mentioned neurotrophic factors in the ADSCs. Moreover, adipogenic and chondrogenic differentiation of ADSCs were induced in-vitro

Results: The assessment of ADSCs identity and purity showed that 90% and 80% of the stem cells were positive for CD90 marker and nestin, respectively. According to RT-PCR results, the above-mentioned neurotrophic factors were expressed in these stem cells. Furthermore, a small number of cells were positive for cresyl violet staining

Conclusion: Adipose tissue contains a stem cell population that seems to be a good multipotential cell candidate for cell replacement therapy

[ effects of using retinoic acid during pregnancy on spermatogenesis and steroidogenesis in mature male rat]

The aim of this study was to investigate the effects of using Retinoic Acid during pregnancy on the spermatogenesis, testosterone and gonadotropin hormones in mature male rat. Pregnant rats were injected by 10, 20 and 30 mg/kg Retinoic acid [all-trans Retinoic Acid] intraperitoneally on the 8.5, 10.5, 12.5 and 14.5 days after copulation. An equivalent amount of the vehicle was similarly injected to corresponding control rats. Then animals did child birth. On time of maturity [10 weeks], from male animals in all of groups blood to determined the amount of hormones and the reproductive organs were separated. Morphometerical and Histological changes were studied in epididym and testis among experimental and control groups. The results were evaluated by using one way ANOVA and Tukey- test. Results indicateed that there were significant decrease in LH and FSH hormones, seminiferous tubules diameter, number of spermatocyte, spermatid and leydig cells experimental groups compared with the control group especially in animals which received 30 mg/kg of retinoic acid [p<0.05]. Also RA is the cause of decrease of the epididymis and deferent weight, and sperms in the epididymis, significantly [p<0.05]. Using of Retinoic Acid during pregnancy decreases the normal spermatogenesis and Steroidogenesis in mature male rats