Sperm Quality in Mouse After Exposure to Low Doses of TCDD

Protective effect of didymin against 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin-induced reproductive toxicity in male rats

PURPOSE

2, 3, 7, 8-Tetrachlorodibenzo-p-dioxin (TCDD) is one of the most potent environmental toxicants, which causes oxidative stress and adversely affects the male reproductive system. The current study aimed to evaluate the ameliorative role of didymin (DDM) against TCDD-induced testicular toxicity.

METHODS

Forty-eight male Sprague-Dawley rats were divided into four equal groups (n=12). (i) Control group, (ii) TCDD-induced group was provided with 10 μg/kg/day of TCDD, (iii) TCDD + DDM group received 10 μg/kg/day of TCDD and 2 mg/kg/day of DDM, and (iv) DDM-treated group was administered with 2 mg/kg/day of DDM. After 56 days of treatment, biochemical, steroidogenic, hormonal, spermatogenic, apoptotic, and histopathological parameters were estimated.

RESULTS

TCDD affected the biochemical profile by reducing the activities of antioxidant enzymes, while increasing the levels of malondialdehyde (MDA) and reactive oxygen species (ROS). Furthermore, it decreased the expressions of steroidogenic enzymes, 3β-hydroxysteroid dehydrogenase (HSD), 17β-HSD, steroidogenic acute regulatory protein (StAR), cholesterol side-chain cleavage enzyme (CYP11A1), and 17α-hydroxylase/17, 20-lyase (CYP17A1), as well as reduced the levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and plasma testosterone. Besides, epididymal sperm count, viability, and motility were decreased, while sperm morphological anomalies were increased. Moreover, TCDD altered the apoptotic profile by up-regulating the expressions of Bax and caspase-3, while downregulated the Bcl-2 expression. Additionally, histopathological damages were prompted due to TCDD administration. However, DDM restored all the TCDD-induced damages owing to its antioxidant, anti-apoptotic, and androgenic potential.

CONCLUSION

Our data suggested that DDM might play its role as a therapeutic agent against TCDD-prompted testicular toxicity.

Rhamnazin ameliorates 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin-evoked testicular toxicity by restoring biochemical, spermatogenic and histological profile in male albino rats

2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD) is a potential environmental toxin that has the ability to affect male reproductive tract. Rhamnazin is a naturally present flavone that displays multiple medicinal properties. Therefore, the current study was designed to determine the mitigative role of rhamnazin against TCDD induced reproductive damage. 48 adult male albino rats were randomly separated into four groups: control, TCDD (10 µgkg-1), TCDD + rhamnazin (10 µgkg-1 + 5 mgkg-1 respectively) and rhamnazin (5 mgkg-1). The trial was conducted for 56 days. TCDD intoxication notably affected superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GSR) and catalase (CAT) activities, besides reactive oxygen species (ROS) and malondialdehyde (MDA) concentrations were augmented. TCDD administration also lowered sperm motility, viability, sperm number, while it augmented the sperm morphological (tail, neck/midpiece and head) anomalies. Moreover, it decreased the levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH) and plasma testosterone. Moreover, TCDD reduced steroidogenic enzymes i.e., 17-beta hydroxysteroid dehydrogenase (17β-HSD), steroidogenic acute regulatory protein (StAR) and 3-beta hydroxysteroid dehydrogenase (3β-HSD) as well as B-cell lymphoma 2 (Bcl-2) expressions, but increased the expressions of Bcl-2-associated X protein (Bax) and cysteine-aspartic acid protease (Caspase-3). Furthermore, TCDD exposure also induced histopathological anomalies in testicular tissues. However, the supplementation of rhamnazin recovered all the mentioned damages in the testicles. The outcomes revealed that rhamnazin can ameliorate TCDD induced reproductive toxicity due to its anti-oxidant, anti-apoptotic and androgenic nature.

Pathological effects of graded doses of aflatoxin B1 on the development of the testes in juvenile white leghorn males

Current experiment was planned to investigate the deleterious effects of the graded doses of aflatoxin B1 (AFB1) on white leghorn male birds. For this purpose, one-hundred birds of 8 weeks of age were divided into 4 equal groups and reared on feed contaminated with different doses of AFB1 for 10 weeks. Group A was kept as a control group and was fed with normal toxin-free diet; groups B, C, and D were offered feed containing 100 ppb, 200 ppb, and 400 ppb of AFB1, respectively. The birds were euthanized at the 4th and 10th week of the experiment. Clinical signs, behavioral changes, absolute and relative organ weight of the testes, and sperm motility were measured. Cellular immune response was observed through carbon clearance assay (CCA), P-HAP, and antibody response against sheep red blood cells (SRBC). Results showed a dose-dependent decline in the immune response of birds with the increase in the level of AFB1 in the feed. A significant decrease in the serum levels of testosterone, prolactin, and LH were observed at the end of the study. Grossly, testicular size and volume were reduced in ABF1 fed birds, while histological examination showed moderate to severe necrosis of testicular parenchyma, with partial to complete arrest of spermatogenesis. Very few spermatozoa were found in group C, while they were almost absent in group D which was offered a diet containing 400 ppb AFB1. The motility of sperms was reduced in all treated groups except control. The abovementioned results showed that AFB1 had severe toxic effects on the reproductive and immunological parameters of WLH male birds in a dose-dependent manner.

The protective effects of capsaicin on oxidative damage-induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin in rats

The present study aimed to investigate the protective role of capsaicin in a rat model of 2,3,7,8-tetracholorodibenzo-p-dioxin (TCDD)-induced toxicity. Exposure to TCDD which is an environmental toxicant causes severe toxic effects in the animal and human tissues. Therefore, the potential protective effect of capsaicin in TCDD-induced organ damage was investigated in rats by measuring thiobarbituric acid reactive substances (TBARS) level, superoxide dismutase (SOD) activity, and glutathione (GSH) level in the heart, liver, and kidney tissues for oxidant/antioxidant balance. Thirty-two healthy adults (250-300 g weight and 3-4 months old) male Wistar albino rats were randomly distributed into four equal groups (n = 8): Control, CAP, TCDD, TCDD + CAP. A dose of 2 μg/kg TCDD or a dose of 25 mg/kg capsaicin were dissolved in corn oil and orally administered to the rats for 30 days. The results indicated that TCDD-induced oxidative stress by increasing the level of TBARS and by decreasing the levels of GSH, and SOD activity in the tissues of rats. However, capsaicin treatment was significantly decreased TBARS levels and was significantly increased GSH level and SOD activity (p < 0.05). In addition, capsaicin (25 mg/kg) significantly attenuated TCDD-induced histopathological alteration associated with oxidative stress in the heart, liver, and kidney tissues (p < 0.05). As capsaicin regulates oxidative imbalance and attenuates histopathological alterations in the rat tissues, it may be preventing agents in TCDD toxicity.

The effects of endocrine disruptors on the male germline: an intergenerational health risk

Environmental pollution is becoming one of the major concerns of society. Among the emerging contaminants, endocrine-disrupting chemicals (EDCs), a large group of toxicants, have been the subject of many scientific studies. Besides the capacity of these compounds to interfere with the endocrine system, they have also been reported to exert both genotoxic and epigenotoxic effects. Given that spermatogenesis is a coordinated process that requires the involvement of several steroid hormones and that entails deep changes in the chromatin, such as DNA compaction and epigenetic remodelling, it could be affected by male exposure to EDCs. A great deal of evidence highlights that these compounds have detrimental effects on male reproductive health, including alterations to sperm motility, sexual function, and gonad development. This review focuses on the consequences of paternal exposure to such chemicals for future generations, which still remain poorly known. Historically, spermatozoa have long been considered as mere vectors delivering the paternal haploid genome to the oocyte. Only recently have they been understood to harbour genetic and epigenetic information that plays a remarkable role during offspring early development and long-term health. This review examines the different modes of action by which the spermatozoa represent a key target for EDCs, and analyses the consequences of environmentally induced changes in sperm genetic and epigenetic information for subsequent generations.

Animal Toxicology Studies on the Male Reproductive Effects of 2,3,7,8-Tetrachlorodibenzo-p-Dioxin: Data Analysis and Health Effects Evaluation

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a well-known environmental poison that exist in the environment for many years. However, its effect on the male reproductive system has not been clearly stated. We conducted a meta-analysis of the effect of TCDD on the male reproductive system of rodents about TCDD. Results showed that that TCDD exposure reduced the testis weight (weighted mean difference [WMD]: -0.035, 95% confidence interval [CI]: -0.046 to -0.025), sperm count (WMD: -35, 95% CI: -42.980 to -27.019), and blood testosterone concentration (WMD: -0.171, 95% CI: -0.269 to -0.073). According to our research results, TCDD can cause damage to the male reproductive system of rodents through direct or indirect exposure. In order to further explore the potential hazards of TCDD to humans, more human-related research needs to be carried out.