Effects of pharmacological doses of niacin on subacute glucocorticoid-induced testicular damage in rats.

Glucocorticoid excess adversely affects male reproduction. This study evaluates effects of pharmacological doses of niacin on testicular structure and function in dexamethasone-treated rats. Adult rats (48) were randomly assigned to 6 equal groups: (1) Negative control (NC): normal rats; (2) Positive control (PC): dexamethasone at 7 mg/kg/day by intraperitoneal injections for 7 days; groups 3-6 (N50, N100, N200, and N400): dexamethasone and concomitant treatment with niacin at 50, 100, 200, and 400 mg/kg/day by oral gavages. Testicular weight and volume of PC rats were significantly lower than the NC group (p < .05). Testicular volume of rats in the N50 and N200 groups was statistically similar to the NC group. Significant decreases in serum testosterone with a slight LH increase were detected in the PC group. Nacin at 50 mg/kg reversed serum testosterone to NC levels and increased serum LH concentration. Niacin only slightly increased epididymal spermatozoa number while all groups of niacin-treated rats had significantly higher percentages of motile spermatozoa compared with the PC group. Hypospermatogenesis, germ cell degeneration and depletion, epithelial vacuolization, and degenerated Leydig cells were observed in PC rats. Lesions were relatively milder in niacin-treated rats. Johnsen scores were also significantly higher in niacin-treated rats. Niacin reduced apoptosis as shown by TUNEL assay. In conclusion, niacin administration at pharmacological doses dose-dependently ameliorates the destructive effects of dexamethasone on sperm motility, Johnsen score, and testicular cell apoptosis in rats with the latter can be considered a decisive mechanism for its positive effects on testis.

Effect of ghrelin on total antioxidant capacity, lipid peroxidation, sperm parameters and fertility in mice against oxidative damage caused by cyclophosphamide.

Cyclophosphamide is a drug used for chemotherapy and as an immune-suppressive in the organ transplantation. Despite its many clinical implications in the treatment of cancers, this drug has toxic effects on the reproductive system. This study aimed to evaluate the effect of ghrelin against the damages caused by cyclophosphamide. In this experimental study, 40 male mice were randomly divided into four groups: (i) control; (ii) cyclophosphamide; (iii) cyclophosphamide + ghrelin; and (iv) ghrelin. Cyclophosphamide (100 mg/kg body weight), once a week, and ghrelin (80 µg/kg body weight), daily, were administered intraperitoneally for 5 weeks. After 5 weeks, the epididymides were removed and the lipid peroxidation, total antioxidant capacity and sperm parameters were examined. The fertility rate was evaluated by performance in vitro fertilisation. In the mice exposed to cyclophosphamide, the number of spermatozoa and viability, as well as total antioxidant capacity, decreased significantly (p < .05). The increase in the abnormal sperm and MDA levels was observed (p < .05). In addition, the fertility rate decreased in this group, while the use of ghrelin significantly improved the above disorders in the treatment group (p < .05). The findings of this study showed that ghrelin attenuates negative effects caused by cyclophosphamide in the sperm parameters and enhances the fertility.

Phenytoin accelerates tendon healing in a rat model of Achilles tendon rupture.

INTRODUCTION: Tendons are vulnerable to various types of acute or chronic injures. Different methods have been investigated to achieve better healing. Phenytoin is a drug which could stimulate fibroblasts to produce collagen. This experimental study was performed to assess the effect of phenytoin on tendon healing in a rat model of tendon rupture. METHODS: Thirty healthy rats were divided into 3 groups, 1) Sham group; 2) Tendon rupture; 3) Tendon rupture+phenytoin (100 mg/kg intraperitoneally) for 21 days. On 21st day after tendon injury, the rats were anesthetized and tendon tissue was sampled for studying by light and electron microscopy. RESULTS: Qualitative and quantitative microscopic comparisons of the repair tissues of both groups were made on the 21st day. The results obtained from light and electron microscopy studies showed that tendon tissue healing was significantly better in phenytoin group compared to the control group (p < 0.05). CONCLUSIONS: Systemic administration of phenytoin may have a positive effect on tendon healing by increasing fibroblast quantity, fibrillar collagen synthesis, vascularity, and suppressing inflammation (Tab. 2, Ref. 25).

Effect of low-frequency electromagnetic field exposure on oocyte differentiation and follicular development.

BACKGROUND: The effect of electromagnetic field (EMF) as an environmental factor on different organs including female reproductive system is of critical concern. The aim of the present study is to evaluate the effect of low-frequency (LF)-EMF on oocyte differentiation and follicular development. MATERIALS AND METHODS: The experiment was carried out in animal lab of Faculty of Medicine Tabriz University of Medical Sciences. For this purpose, the BALB/c mice were divided into control and experimental group in animal lab. The pregnant mice in the experimental group were exposed to 3 mT EMF field, 4 h/day during the pregnancy period. The LF-EMF was produced by a system using 50 Hz alternative current, in the control group the pregnant mice were kept in a similar condition without exposure to EMF. The neonatal mice from both groups were sacrificed immediately after birth and their ovary was dissected apart and prepared for light and electron microscopy. RESULT: Microscopy revealed that in the experimental group, in comparison to control group, oocyte nests were mostly broken and irregularly arranged. The primordial follicles were less developed and nuclei of oocytes with an electron microscope appeared heterochromatic, shrunken and had vacuolated cytoplasm. CONCLUSION: It is concluded that exposure to EMF during the developmental period could affect both oocyte differentiation and folliculogenesis and may result in reduced fertility, by decreasing ovarian reservoir.

Ultrastructural and morphometrical changes of mice ovaries following experimentally induced copper poisoning.

BACKGROUND: Copper (Cu) is an essential trace element involved in normal reproduction but its overexposure may produce some detrimental effects. The aim of this study was to investigate the effects of copper sulfate poisoning on morphometery of mice ovarian structures and probable intracellular changes. METHODS: Thirty mature female mice were randomly allocated to control and two treatment groups. In treatment groups, two different doses of copper sulfate including 100 mg/kg and 200 mg/kg in 0.2 cc were applied once a day for 35 consecutive days by gavage. Control animals received normal saline using the same volume and similar method. Animals from each experimental group were sacrificed 14 and 35 days after the beginning of drug administration and the left ovaries were removed for stereological evaluations by light microscopy and right ovaries were obtained for preparing electron microscopic sections. RESULTS: The morphometrical results showed that only the number of antral follicles was decreased by 100 mg/kg copper sulfate on day 14 compared to the control group (P=0.043). Hence, higher copper dose or longer consumption period significantly reduced different classes of follicles and corpora lutea. With 100 mg/kg copper sulfate some mild ultrastructural cell damages such as decrease of zona pellucida thickness, limited vacuolated areas and nuclear envelop dilation were seen on day 14. Higher or longer Cu administration produced more detrimental effects including more vacuolated areas, presence of secondary lysosomes, irregularity in cell shape and segmented nuclei with condensed and marginated chromatin and more enlarged and damaged mitochondria. CONCLUSION: New evidences of early as well as late intracellular damages of copper has been presented by accurate stereological and ultrastructural methods. Antral follicles was the most susceptible cells with the lower and shorter copper consumption and long term or higher dose of copper affected the whole of ovarian structures.

Protective effect of pentoxyfilline in renal toxicity after methotrexate administration.

INTRODUCTION: Nephrotoxicity is an important side-effect of treatment with Methotrexate (MTX). Pentoxifylline (PTX) is an anti-inflmmatory and anti-oxidant agent. We hypothesized that pentoxifylline may affords renal protection by downregulating TNF-alpha as well as by improving cellular anti-oxidant activity. MATERIALS AND METHODS: Forty five male Wistar rats were assigned to 3 groups of 15 animals each: Group 1: control group (0.9% saline). Group 2: MTX; injected with 20 mg/kg MTX intraperitoneally (i.p.). Group 3: MTX + PTX injected i.p. MTX (20 mg/kg) + PTX (50 mg/kg) i.p. PTX was administered since 3 days before MTX administration and continued for 6 days. After 6 days rats were anesthetized and serum sampled and renal tissue removed for biochemical and histological evaluation. RESULTS: Data showed that glutathione peroxidase (GPx), superoxide dismutase (SOD) activities were lower in PTX + MTX group comparing to MTX group significantly (p < 0.05). Renal tissue injury index and percent of TUNEL positive cells, renal tissue malondialdehyde (MDA) levels, serum BUN (Blood Urea Nitrogen), creatinine (Cr) and TNF-alpha levels were higher in MTX group comparing to MTX+PTX group significantly (p < 0.05). CONCLUSIONS: In this study, the increased level of tissue MDA and serum TNF-alpha level together may be suggested that the underlying mechanism is related to direct toxicity of MTX rather than blockage in folate synthesis in kidneys. PTX administration also attenuated renal tissue injury and number of apoptic cells and suppressed the elevation of BUN and Cr levels. However, further studies are essential to elucidate the exact mechanisms of MTX-induced renal toxicity, and protection and the effect of PTX.

Effect of dietary and topical Celecoxib on expression of bcl-2, bax, c-erb-B2 and Ki67 in carcinogen-induced tongue carcinoma in rat.

The aim of the study is to determine the effect of Celecoxib administration, dietary or topical, on expression of Ki-67, c-erb-B2, bcl-2 and bax genes in rat tongue by the immunohistochemistry methods and also tdt-mediated dupt-biotin nick end labeling assay in order to explore their role in malignant transformation and the proliferation rate, apoptosis rate in tongue squamous cell carcinoma. Effects of celecoxib on tongue carcinogenesis were investigated in 40 adult male Sprague Dawley 3-3.5 months rats initiated with 30 ppm 4-nitroquinoline-1-oxide. The immunohistochemical expression of Ki-67, bcl2, bax and c-erb-B2 were also examined for analysis of the effects of Celecoxib on tongue carcinogenesis. Differences among groups were statistically analyzed with one-way analysis of variance (SPSS-13, p < 0.05). At week 8, the incidence of tongue precancer lesions was reduced by Celecoxib and there were significant differences in the average expression of Ki-67 (p = 0.00), c-erb-B2 (p = 0.01), bax (p = 0.02), bcl2 (p = 0.02) and also in TUNEL assay (p = 0.00). The results suggest probably that the level of c-erb-B2, bcl-2 and bax expression could show behavior of squamous cell carcinoma in initiation phase of developing carcinoma.

Morphometrical and intracellular changes in rat ovaries following chronic administration of ghrelin.

The aim of our investigation was to examine the influence of chronic administration of ghrelin on the rat ovarian state. Morphometrical and intracellular changes in the ovary of 35-d female Wistar rats after sc injection of 1 nmol of ghrelin for 10 consecutive days were studied. Control animals (n=10) were injected with normal saline using similar method. The ovaries were collected on days 1 and 6 after last injection from each group and subjected to light microscopic morphometric and electron microscopic analysis. It was demonstrated that the number of corpora lutea was significantly lower and the number of ovarian follicles was higher in the treated group on days 1 and 6, than in control (P<0.01). Moreover, the mean diameter of each follicle, corpora lutea, luteal cell, theca layer, oocyte and zona plucida, but not of granulosa layer, as well as the whole ovarian volume were significantly lower in the treated animals at days 1 and 6 (P<0.05). Electron microscopic analysis also indicated some intracellular changes associated with apoptosis and cell death such as presence of secondary lysosome, apoptotic bodies, nuclear chromatin condensation as well as margination, nuclear segmentation and vacuolization of cytoplasm of granulosa and theca cells. Our observations provides novel evidences for inhibitory influence of ghrelin on rat ovarian structures and, therefore, for the role of ghrelin as suppressor of female reproductive system.

The role of ghrelin on the morphometry and intracellular changes in the rat testis.

Recent studies have implicated the peripheral actions of ghrelin in reproductive tissues. Expression of the functional ghrelin receptor, GHS-R1a, has been shown in Sertoli and Leydig cells as well as seminiferous tubules. Therefore, we investigated the effects of chronic administration of ghrelin on morphometry of testicular cells and its probable intracellular alterations. Thirty 45-day male Wistar rats were scheduled for the study and were divided into control and treatment groups. In the treatment group, 1nmol of ghrelin was administered as sc injection for 10 consecutive days or vehicle (physiological saline) to the control rats. Testes were taken by killing of rats on days 5, 15 and 40 after last injection and underwent for photomicrograph and electronmicrograph evaluations as well as stereological estimations. Testicular histomorphometry revealed a significant decrease in the different cell types except for spermatogonia in the treatment animals (P<0.01). Such a cellular decrease was also found in the stereological estimations in this group. Likewise, seminiferous tubules diameter and their germinal epithelium thickness decreased in the treated rats (P<0.01). In intracellular observations, much vacuolated mitochondria, limited endoplasmic reticulum, lesser intracellular organels and several detachment areas between cell membrane and its basement membrane were detected in the ghrelin-treated group. These findings indicate that ghrelin has anti-proliferative effects on different testicular cell types and is a negative modulator of male reproductive system.