Aloe vera toxic effects: expression of inducible nitric oxide synthase (iNOS) in testis of Wistar rat

Objective(s): Nitric oxide (NO), a product of inducible nitric oxide synthase (iNOS), contributes in germ cell apoptosis. This study was aimed to evaluate the effects of Aloe vera gel (AVG) on male Wistar rat reproductive organ, serum NO level, and expression of iNOS gene in leydig cells. Materials and Methods: Adult male Wistar rats (n=36) were used for experiments in three groups. The experimental groups were orally administered with the AVG extract solution once-daily as follow: 150 mg.kg(-1); group A, 300 mg.kg(-1); group B, and only normal saline; group C (control group). They were mated with untreated females and the reproductive and chemical parameters were assessed for each group, including semen quality, serum testosterone, sperm fertility, gonad and body weight, serum NO concentration (by the Griess method), and iNOS gene expression (using RT-PCR). Results: The testes weight, serum testosterone, as well as sperm count and fertility of the AVG treated groups were significantly reduced when compared to the control (P<0.001). Concentration of serum NO was significantly increased (37.1 +/- 4.63 mu M) in the administrated group with higher AVG concentration, compared to the control group (P<0.001; 10.19 +/- 0.87 mu M); however, iNOS mRNA expression was increased in the treated animals (P<0.001). Conclusion: iNOS may play a functional role in spermatogenesis via apoptosis, reducing sperm count, but further studies are needed to illustrate the mechanisms by which AVG exerts its negative effects on spermatogenesis and sperm quality

Effects of Feeder Layers, Culture Media, Conditional Media, Growth Factors, and Passages Number on Stem Cell Optimization

Stem cells are undifferentiated and self-renewal cells which could be obtained from the body or artificially derived from an adult somatic cell by forced expression of specific genes. In recent years stem cells are widely used in laboratory for tissue engineering and therapeutic applications. There are different factors and conditions that affect the stem cell culture such as feeder layers, atmosphere, kind of medium, growth factors, passages number, and conditional media with animal or human sources. Optimization of stem cell culture for medical approaches and regenerative medicine is important. Therefore, in the present study, the effect of these factors and agents on optimization of stem cell culture has been discussed. This review study showed that optimization of feeder layer, atmosphere, and using supplemented media with essential growth factors could help in maintaining the stem cells in undifferentiated state in vitro. The present study indicated that optimization of stem cell culture depends on the kind of each cell type and using stem cells in low passage number could decrease chromosomal abnormalities and DNA damages. For inhibiting the stem cell contamination by feeder cell lines, culture of these cells on feeder free systems like Matrigel matrix in conditioned media supplemented with essential growth factors is useful. Also, for eradicating immune system responses and reducing the risk of animal pathogen transfer, culture of stem cells on human feeder in optimized media is suitable for therapeutic approaches and regenerative medicine

Effects of lentiviral vectors on DNA damage of human dermal fibroblasts (HDFs)

In present study we evaluated the DNA damages and cytogenetic stability of transducted and non-transducted human dermal fibroblasts (HDFs) by enhanced green fluorescent protein (eGFP) lentiviral vector using karyotyping, comet assay, and molecular techniques. HDFs were isolated from human foreskin samples and eGFP-expressing lentiviral vector were transfected into HEK-293T cells to produce lentiviruses. Then, HDFs at passage 2 were transducted with concentrated eGFP lentivirus and transducted HDFs were detected by fluorescent microscope. The expression levels of cell cycle genes include two subunits of anaphase promoting complex (APC) in transducted and nontransducted HDFs were measured by quantitative real-time PCR and finally, karyotype test and comet assay was performed to evaluate the DNA damages and cytogenetic stability in both groups. The results of karyotype analysis were not showed any abnormalities in karyotype of transducted HDFs by eGFP in compared to normal cells. The mean values of alkaline comet assay parameters on non-transducted (normal cells), eGFP-transducted group and positive control (H2O2 treatment) were calculated by CaspLab software. The comparison of mean difference of comet assay parameters include tail length, comet length, tail moment, and Olive tail moment by T test between eGFP-transducted HDFs and other groups (positive control and non-transducted HDFs) were statistically significant (p≤0.05). The alkaline comet assay on HDFs in eGFP-transducted group was showed small tail and indicated slight genetic damage compared with non-transducted group. Furthermore, the analysis of real-time PCR on expression of APC2 and APC7 genes in non-transducted HDFs compared with eGFP-transducted HDFs were not significant (p≤0.05). These findings indicated that integration of lentiviral vectors in first passage of transducted HDFs could not disturb the DNA structure and create chromosome instability. So in genetic engineering and gene transformation these vectors in first passages are useful

A study of cytogenetic stability of induced pluripotent stem cells using karyotyping and comet assay techniques

Background & Aims: Induced pluripotent stem cells (iPSCs) have the capability to undergo unlimited selfrenewal and differentiation into all cell types in the body. These cells are artificially derived from a nonpluripotent cell, typically human dermal fibroblasts (HDFs). The study of cytogenetic stability of these cells, in order to use iPS cells and apply studies in therapeutic applications, is essential. Methods: In the present experimental study, HDFs were isolated and cultured from human foreskin samples. The cytogenetic stability of these cells was evaluated in early passages (1-3) of HDFs using karyotype test and alkaline comet assay technique. The HDF cells treatment with hydrogen peroxide (H2O2) was used as a positive control for alkaline comet assay. The iPS cells with low passage (4-7) derived from reprogrammed HDFs were cultured on mouse embryonic fibroblast (MEF) feeder layer and cytogenetic stability of these cells were evaluated in early passages using karyotype test and alkaline comet assay technique. Results: The iPS cells in early passages (4-7) had normal karyotype (46, XY) and DNA damage and comet were not observed in these cells. In addition, HDF cells showed normal karyotype in early passages (1-3), but using comet assay, abnormality and DNA damages were observed in positive control (HDFs treated with H2O2). The comparison of alkaline comet assay parameters of iPS and HDF cells with positive control group showed statistically significant differences (P < 0.05). Conclusion: Since the comet assay is a sensitive technique for finding DNA damage, it is best if cytogenetic stability of these cells were evaluated before performing functional experiments on iPS cells. Therefore, for the precise evaluation of DNA damage and cytogenetic stability of iPS cells, the two techniques could complement each other. © 2015, Kerman University of Medical Sciences. All rights reserved

The assessment of lentiviral vectors application for gene transformation in human dermal fibroblasts (HDFs)

چکیده: زمینه و هدف: سلول های بنیادی پرتوان القایی Induced pluripotent stem cells= iPSc))، سلول های اولیه و تمایز نیافته ای هستند که قادر به ایجاد تقریباً هر نوع سلولی در بدن می باشند. هدف از پژوهش حاضر تولید و استفاده مؤثر از وکتور لنتی ویروسی TetO-FUW-OSKM جهت انتقال ژن ها به سلول های فیبروبلاست انسانی ((HDFs= Human fibroblast cells و در نهایت ارزیابی عملکرد این وکتور بود. روش بررسی: در این مطالعه تجربی پس از جداسازی و کشت سلول های HDF، وکتور لنتی ویروسی TetO-FUW-OSKM (به عنوان پلاسمید انتقال دهنده) حاوی ژن های برنامه ریزی مجدد همراه با پلاسمیدهای PsPAX2 و PMDG2 (به عنوان پلاسمیدهای کمکی لازم برای بسته بندی ویروس) به لاین سلولی HEK-293T جهت تولید ویروس ها ترانسفکت شدند. محیط رویی سلول های HEK-293T حاوی ویروس های تولید شده پس از 48 و 72 ساعت برداشت شد و این ویروس ها جهت برنامه ریزی مجدد سلول های HDF به این سلول ها ترانس داکت گردیدند. یافته ها: نتایج این مطالعه نشان دهنده تولید موفقیت آمیز وکتور لنتی ویروسی TetO-FUW-OSKM، کارایی مؤثر روش انتقال ژن با استفاده از وکتورهای لنتی ویروسی و بیان مناسب فاکتورهای رونویسی در سلول های HDF پس از ترانس داکشن بود. نتیجه گیری: با توجه به این یافته ها می توان از وکتورهای لنتی ویروسی جهت انتقال ژن و برنامه ریزی مجدد سلول های بالغ از قبیل HDF در مطالعات بعدی و تولید سلول های iPS استفاده کرد

Comparison between the cultures of human induced pluripotent stem cells (hiPSCs) on feeder- and serum-free system (Matrigel matrix), MEF and HDF feeder cell lines

Human induced pluripotent stem cells (hiPSCs) are a type of pluripotent stem cells artificially derived from an adult somatic cell (typically human fibroblast) by forced expression of specific genes. In recent years, different feeders like inactivated mouse embryonic fibroblasts (MEFs), human dermal fibroblasts (HDFs), and feeder free system have commonly been used for supporting the culture of stem cells in undifferentiated state. In the present work, the culture of hiPSCs and their characterizations on BD Matrigel (feeder- and serum-free system), MEF and HDF feeders using cell culture methods and molecular techniques were evaluated and compared. The isolated HDFs from foreskin samples were reprogrammed to hiPSCs using gene delivery system. Then, the pluripotency ability of hiPSCs cultured on each layer was determined by teratoma formation and immunohistochemical staining. After EBs generation the expression level of three germ layers genes were evaluated by Q-real-time PCR. Also, the cytogenetic stability of hiPSCs cultured on each condition was analyzed by karyotyping and comet assay. Then, the presence of pluripotency antigens were confirmed by Immunocytochemistry (ICC) test and alkaline phosphatase staining. This study were showed culturing of hiPSCs on BD Matrigel, MEF and HDF feeders had normal morphology and could maintain in undifferentiated state for prolonged expansion. The hiPSCs cultured in each system had normal karyotype without any chromosomal abnormalities and the DNA lesions were not observed by comet assay. Moreover, upregulation in three germ layers genes in cultured hiPSCs on each layer (same to ESCs) compare to normal HDFs were observed (p<0.05). The findings of the present work were showed in stem cells culturing especially hiPSCs both MEF and HDF feeders as well as feeder free system like Matrigel are proper despite benefits and disadvantages. Although, MEFs is suitable for supporting of stem cell culturing but it can animal pathogens transferring and inducing immune response. Furthermore, HDFs have homologous source with hiPSCs and can be used as feeder instead of MEF but in therapeutic approaches the cells contamination is a problem. So, this study were suggested feeder free culturing of hiPSCs on Matrigel in supplemented media (without using MEF conditioned medium) resolves these problems and could prepare easy applications of hiPSCs in therapeutic approaches of regenerative medicine such as stem-cell therapy and somatic cell nuclear in further researches