S.B. Sainath

Protective effects of N-acetylcysteine against arsenic-induced oxidative stress and reprotoxicity in male mice

Arsenic is a well-known environmental toxic metalloid element and carcinogen that affects multiple organ systems including tissue lipid peroxidation and reproduction. The present study was aimed to investigate the protective role of N-acetylcysteine (NAC) on arsenic-induced testicular oxidative damage and antioxidant and steroidogeneic enzymes and sperm parameters in mice. Arsenic was administered through drinking water to mice at a concentration of 4.0 ppm sodium arsenite (actual concentration 2.3 ppm arsenic) for 35 days. The body weight of treated mice did not show significant change as compared with the control mice. In arsenic exposed mice there was a significant decrease in the weight of the testis, epididymis and prostate gland as compared with the control animals. Significant reduction was observed in epididymal sperm count, motile sperms and viable sperms in mice exposed to arsenic indicate decreased spermatogenesis and poor sperm quality. The activity levels of testicular 3β- and 17β-hydroxysteroid dehydrogenases and circulatory levels of testosterone were also decreased in arsenic treated mice indicating reduced steroidogenesis. A significant increase in the activities of lipid peroxidation and a significant decrease in the activities of antioxidant enzymes were observed in the testis of mice exposed to arsenic. In addition, significant increase in the testicular arsenic levels was observed during arsenic intoxication. No significant changes in the oxidation status and selected reproductive variables were observed in the N-acetylcysteine alone treated mice. Whereas, intra-peritoneal injection of NAC to arsenic exposed mice showed a significant increase in the weights of reproductive organs, reduction in arsenic-induced oxidative stress in the tissues and improvement in steroidogenesis over arsenic-exposed mice indicating the beneficial role of N-acetylcysteine to counteract arsenic-induced oxidative stress and to restore the suppressed reproduction in male mice.

Protective role of Centella asiatica on lead-induced oxidative stress and suppressed reproductive health in male rats

Centella asiatica has been mentioned in ancient ayurvedic text of the Indian system of medicine for its properties to promote intelligence. The objective of the present study was to investigate the beneficial effects of C. asiatica on lead-induced oxidative stress and suppressed reproductive performance in male rats. Significant decrease in the weights of testes and epididymis were observed in lead treated animals. Exposure to lead acetate significantly increased malondialdehyde levels with a significant decrease in the superoxide dismutase and catalase activities in the liver, brain, kidneys and testes of rats. Epididymal sperm count, viable sperms, motile sperms and HOS-tail coiled sperms decreased significantly in lead-exposed rats. Testicular steroidogenic enzyme activities also decreased significantly in lead-exposed rats. No significant changes in the selected reproductive variables were observed in the plant extract alone treated rats. Whereas, co-administration of aqueous extracts of C. asiatica to lead exposed rats showed a significant increase in the weights of reproductive organs, reduction in lead-induced oxidative stress in the tissues and improvement in selected reproductive parameters over lead-exposed rats indicating the beneficial role of C. asiatica to counteract lead-induced oxidative stress and to restore the suppressed reproduction in male rats.

Lead acetate induced reproductive and paternal mediated developmental toxicity in rats

Lead was administered orally to adult male rats at exposure level of 273 or 819 mg/L (0.05% or 0.15% lead acetate, respectively) for 45 days via drinking water. At the end of the exposure period, control and experimental males were mated with untreated females. Of the females mated with treated males, 73.3% in the 0.05% group and 53.33% in the 0.15% group showed copulatory plugs. Significant decrease in number of implantations and pre- and post-implantation loss was also observed in females mated with treated males. Significant decrease in the weight of the reproductive organs, reduction in epididymal sperm count, motile sperm and viable sperm were observed in lead-exposed rats indicating decreased sperm production and deteriorated sperm quality. Significant decrease in serum testosterone levels were also observed in treated rats indicating decreased steroidogenesis. The decreased serum testosterone levels and deteriorated sperm quality might be responsible for the suppressed reproduction in rats after exposure to lead.

Prenatal di-n-butyl phthalate exposure alters reproductive functions at adulthood in male rats.

This study was aimed to investigate the reproductive health in adult male rats exposed to di‐n‐butyl phthalate (DBP) during embryonic development. Pregnant rats were injected with DBP and F1 male rats were weaned and on postnatal day 100, used for mating with normal cycling females to assess reproductive performance. After completion of cohabitation period, rats were analyzed for other reproductive end points. Transplacental exposure to DBP significantly decreased fertility in adult male rats. Prenatal exposure to DBP significantly decreased sperm density, number of motile sperms, viable sperms, and hypoosmotic swelling tail coiled sperms with an increase in morphological abnormalities in sperms. Testicular steroidogenic enzyme activity levels and serum testosterone levels were significantly decreased in rats exposed to DBP during embryonic development. In conclusion, transplacental exposure to DBP impairs male reproductive performance by decreasing steroidogenesis and spermatogenesis.

Reproductive Endocrinology of Female Crustaceans: Perspective and Prospective

Reproduction in crustaceans is a highly complex process that requires precise coordination of external and internal factors to be successful. The field of crustacean reproductive endocrinology has moved from the classical approach of endocrinological techniques such as extirpation and additive methods, to the modern era of advanced biochemical, immunological, molecular biology and recombinant DNA technology methods. During last two decades, extensive endeavor has been captivating on the crustacean endocrines regulating reproduction, to authenticate their roles in the regulation of reproduction as well as their biochemical and molecular mechanism of action. In the present chapter, we have tried to recapitulate recent developments in molecular advances taken place in the reproduction regulation of crustacea via hormones, opioids, neurotransmitters and other molecules. In addition to providing a review of the scientific literature, we have also included our perspectives.

What do we (need to) know about the melatonin in crustaceans

Melatonin (N-acetyl-5-methoxy-tryptamine) was first discovered from the bovine pineal gland extract in 1958. Since then, its synthesis, metabolism, physiological, and patho-physiological functions are well studied in vertebrates; there is an increasing recognition of melatonin in invertebrates and especially in crustaceans. The presence of melatonin in crustaceans is now well documented and some functional aspects in the framework of crustacean biology have been demonstrated. This review aims at giving a comprehensive overview of the various physiological events regulated by this pleiotropic hormone. Topics include: glucose homeostasis, regulation of reproduction, molting, limb regeneration, and antioxidant properties. Finally, perspectives on current and possible research are offered.

Embryonic exposure to octylphenol induces changes in testosterone levels and disrupts reproductive efficiency in rats at their adulthood.

The purpose of the present study was to investigate the effects of prenatal exposure to octylphenol (OP) at the dose of 50mg/kg body weight on days 1, 7 and 14 of pregnancy on reproductive health of male rats at adulthood. F1 male rats from control and OP exposed animals were weaned and maintained up to postnatal day (PND) 100. The indices of testis, epididymis and seminal vesicles were significantly decreased in male rats exposed to OP during embryonic development when compared with controls. Significant reduction in the epididymal sperm count, viable sperms and motile sperms and number of tail coiled sperms (HOS-test) were observed in experimental rats when compared to control rats. The levels of serum testosterone and also activity levels of testicular hydroxysteroid dehydrogenases were significantly decreased with a significant increase in the serum follicle stimulating and leutinizing hormones in experimental rats. Furthermore, embryonic exposure to OP caused significant down regulation of StAR, 3ß hydroxysteroid dehydrogenase and 17ß hydroxysteroid dehydrogenase mRNAs in testis of adult rats as compared to control rats. The results of fertility studies revealed that there was an increase in the mating index in experimental rats with an increase in the pre- and post-implantation losses in rats cohabited with treated animals indicating poor male reproductive performance.

Recovery of suppressed male reproduction in mice exposed to progesterone during embryonic development by testosterone

The present study aimed to examine whether transplacental exposure to progesterone caused male reproductive abnormalities and whether the changes can be reversed after testosterone administration. Progesterone was injected to mice on day 1, 3, and 7 of pregnancy. The male pups (F1 generation) were allowed to grow for 50 days and assessed for reproductive performance. Gestational exposure to progesterone (7 mg/kg body weight) resulted in significant body weight gain with a decrease in reproductive tissue indices in mice. Total sperm count, viable sperm, and motile sperm decreased in experimental mice. Hypo-osmotic swelling test revealed that experimental mice sperm membrane integrity was severely altered. The activity levels of testicular steroidogenic marker enzymes (hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase cluster (HSD3B) and hydroxysteroid (17-beta) dehydrogenase 1 (HSD17B)) decreased significantly in mice exposed to progesterone during embryonic development when compared with the controls. The levels of serum testosterone decreased with an increase in serum FSH and LH in mice exposed to progesterone during embryonic development. Prenatal exposure to progesterone caused significant reduction in the number of spermatozoa and increase in the lumen of seminiferous tubule. The experimental mice that cohabited with normal females showed fertility reduction. Administration of testosterone (4.16 mg/kg body weight) on postnatal day 20, 30, and 40 to progesterone-exposed prenates resulted in recovery of progesterone-induced suppressed male reproduction. It is suggested that the impairment of male reproduction in mice exposed to progesterone during embryonic development could be mediated through the inhibition of testosterone production. These results also indicate that in utero exposure to progesterone affects male reproduction and that supplementation of testosterone restores the suppressed male reproduction.

Melatonergic regulation of hemolymph sugar levels in the freshwater edible crab, Oziotelphusa senex senex

In this study, the hyperglycemic effect of melatonin in the freshwater edible crab, Oziotelphusa senex senex, is investigated. Injection of melatonin induced hyperglycemia in a dose-dependent manner. Administration of melatonin produced hyperglycemia in both intact and eyestalk-ablated crabs. Bilateral eyestalk ablation resulted in significant increase in the total carbohydrates and glycogen levels with a significant decrease in phosphorylase activity in the hepatopancreas and muscle of the crabs. Injection of melatonin resulted in significant decrease in the total carbohydrate and glycogen levels, with an increase in phosphorylase activity in hepatopancreas and muscle of both intact and eyestalk-ablated crabs. From the results, it is hypothesized that melatonin-induced hyperglycemia in the crab, O. senex senex, is not mediated by eyestalk hyperglycemic hormone.

Cadmium and mercury-induced hyperglycemia in the fresh water crab, Oziotelphusa senex senex: Involvement of neuroendocrine system

The effect of exposure to sublethal concentrations of cadmium chloride and mercuric chloride on hemolymph glucose levels of the freshwater crab, Oziotelphusa senex senex, was studied. Intact crabs exposed to cadmium or mercury exhibited a significant hyperglycemia compared to controls, but no significant differences in hemolymph glucose level were detected among the eyestalkless crabs after exposure to metals, suggesting that the effect of metals could be on the sinus gland in the eyestalks, increasing secretion of the hyperglycemic hormone. To test this hypothesis, eyestalks were collected from control and metal exposed crabs, and tested for hyperglycemic effect and also for the hyperglycemic hormone levels. The levels of hyperglycemic hormone and the hyperglycemic effect were significantly low in the eyestalks collected from metal exposed crabs when compared with eyestalks from control crabs. These results strongly suggest that metals act, at least in part, by triggering the secretion of hyperglycemic hormone from the eyestalk.