Influence of gossypol on the secretory function of cultured rat sertoli cells

In vitro effects of glyphosate and Roundup on Sertoli cell physiology

Roundup (R), a formulation that contains glyphosate (G) as the active ingredient, is a commonly used nonselective herbicide that has been proposed to affect male fertility. It is well known that an adequate Sertoli cell function is essential to maintain germ cell development. The aim of the present study was to analyze whether G and R are able to affect Sertoli cell functions, such as energy metabolism and blood-testis barrier (BTB) integrity. Sertoli cell cultures from 20-day-old rats were exposed to 10 and 100 ppm of G or R, doses which do not decrease cell viability. Neither G nor R caused impairment in lactate production or fatty acid oxidation. G and R decreased Transepithelial Electrical Resistance, which indicates the establishment of a Sertoli cell junction barrier. However, neither G nor R modified the expression of claudin11, ZO1 and occludin, proteins that constitute the BTB. Analysis of cellular distribution of claudin11 by immunofluorescence showed that G and R induced a delocalization of the signal from membrane to the cytoplasm. The results suggest that G and R could alter an important function of Sertoli cell such as BTB integrity and thus they could compromise the normal development of spermatogenesis.

Genomic and proteomic analyses of 1,3-dinitrobenzene-induced testicular toxicity in Sprague-Dawley rats

1,3-Dinitrobenzene (DNB) is an industrial intermediate and testicular toxicant that has been shown to target Sertoli cells. The mechanism of action of DNB in the testis, however, is unclear. To investigate global alterations in gene or protein expression during testicular toxicity, testes from rats treated orally with DNB were subjected to microarray and two-dimensional gel electrophoresis (2-DE) analyses. Histopathological abnormalities were detected in the testes of the DNB-treated rats. Microarray analysis revealed that, during early testicular toxicity, several genes involved in apoptosis, germ cell/Sertoli cell junction, and tight junction signaling pathways were differentially expressed. Based on 2-DE analysis, 36 protein spots showing significantly different expression during early testicular toxicity were selected and identified. Network analysis of the identified proteins revealed that these proteins are associated with cellular development or reproductive system diseases. Collectively, these data will help clarify the molecular mechanism underlying testicular toxicity in DNB-exposed rats.

Review on Research of Suppression Male Fertility and Male Contraceptive Drug Development by Natural Products

Male contraceptive development in the present scenario is most viable aspect of research due to uncontrolled population growth in the world. In this respect investigators are busy to find out a safe male contraceptive drug. Researchers have started their finding for a suitable drug from natural sources because these are safe and easily acceptable for common man, most of natural sources are plants and their products. In this review 137 plants and their effects on reproduction and reproductive physiology are summarized. Some of them have intense effect on male reproductive system and do not produce any side effects. Reproductive toxicological studies are also important aspects of these kinds of researches, so it is important that drugs are safe and widely acceptable. An ideal male contraceptive can influence semen, testes, hormone level, accessory reproductive organs and general physiology of animals and produced some alterations. Many plants in this review are showing antifertility as well as antispermatogenic effects, so these may be used for further study for contraceptives development but it is important to find out the mechanism of reaction and further laboratory and clinical research on some plants are needed for final male contraceptive drug development. In conclusion this review will help for finding suitable plant products for male contraceptive clinical and laboratory studies.

Epididymis-Specific Pathologic Disorders in Rats Exposed to Gossypol from Weaning Through Puberty

Previous work in our laboratory revealed that the pubertal period of reproductive development in the male rat was particularly vulnerable to gossypol exposure, with a higher frequency of round structures in the lumen of the cauda epididymidis in the treated rats. Herein, we utilized hemicastration and electron microscopy to confirm that the epididymis is a definitive target of gossypol. Although exposure to gossypol from weaning through puberty caused a significant decrease in daily sperm production, as well as in the concentration of sperm in the epididymis, serum testosterone levels and reproductive organ weights were not altered. In gossypol treated rats, sperm morphology was compromised severely, but the epithelium in testis and epididymis appeared morphologically normal. Ultrastructural examination revealed that round structures, present only in gossypol exposed males, represented: (1) principal cells exfoliated from the epididymal epithelium; (2) epididymal epithelial cell cytoplasm containing degenerating sperm; and (3) degenerating epithelial cells, consisting of vesicles and particles of different sizes, forms and densities. Taken together, the data confirm that gossypol targets the epididymis, disturbing both the structure and function of this organ, and presumably disrupts sperm maturation.

Effect of antispermatogenic agents on cell marker enzymes of rat Sertoli cells in vitro

OBJECTIVE

To examine the role of Sertoli cells in the antispermatogenic action of two nonsteroidal male contraceptive compounds (CDRI-84/35 and gossypol) by evaluating their effect on some key parameters of Sertoli cell function in vitro.

METHODS

Primary cultures of Sertoli cell were established from 18-day-old rat testis and treated on day 5 with different concentrations (1.0, 0.1, 0.01, and 0.001 mM) of either CDRI-84/35 or gossypol in vitro. Lactate (secretion), along with beta-glucuronidase, gamma-glutamyl transpeptidase, lactate dehydrogenase (LDH) and aromatase activities, was measured in these cells to examine the functions targeted by antispermatogenic agents in Sertoli cells.

RESULTS

CDRI-84/35 significantly affected Sertoli cell parameters (stimulation in most of the cases) that are important for germ cell development like lactate secretion, LDH activity, aromatase activity (estradiol secretion) and so on. Gossypol in comparison to CDRI-84/35 had a more severe effect on Sertoli cells with complete inhibition of enzyme activities at higher concentrations.

CONCLUSION

It is probable that the antispermatogenic action of CDRI-84/35 and gossypol is routed through Sertoli cells by disruption of important cell functions that support spermatogenesis in vivo. However, the two compounds appear to have different course of action in Sertoli cells, ultimately leading to spermatogenic failure.

Sertoli cells as a target for reproductive hazards

Male fertility can be impaired by various toxicants. Some of them are known to target mainly Sertoli cells, which play an essential role in spermatogenesis. In this study, the in vitro response of immature rat Sertoli cells to various environmental pollutants, including pesticides, oestrogenic compounds and heavy metals, has been investigated. Mitochondrial dehydrogenase activity has been used to measure Sertoli cell viability, while production of lactate and secretion of inhibin B have been used as general and specific cell markers. Sertoli cell viability was not affected after 24-h exposure to lindane, DDT, ethinyloestradiol or bisphenol A in the concentration range analysed (up to 100, 25 or 50 microM, respectively). In contrast, mercury(II) (EC50 = 31 microM) and cisplatin (15% decrease in viability at 100 microM) induced some cytotoxic effect. With the exception of the pesticide DDT, all chemicals investigated induced a significant dose-dependent increase in lactate production after 24-h exposure to Sertoli cells. Owing to the cytotoxic effect of mercury(II), lactate levels dropped again at concentrations above 20 microM. The pesticide lindane (but not DDT) and both oestrogens significantly increased the production of the Sertoli cell specific hormone inhibin B without affecting cell viability. In contrast, the heavy metals mercury(II) and platinum(II) markedly decreased inhibin B levels. This sharp decrease was already significant at metal concentrations that reduced Sertoli cell viability only moderately (10-15%). In conclusion, the secretion of lactate and inhibin B by immature rat Sertoli cells seems to be a useful and sensitive marker with which to explore potential Sertoli cell toxicants.

In vitro effect of gossypol acetate on yellow perch (Perca flavescens) spermatozoa

Gossypol, a known antispermatogenic agent from the cotton plant genus Gossypium, was found to inhibit yellow perch sperm motility in vitro and lactate dehydrogenase activity in spermatozoa when used in a dose-dependent manner. This toxin also significantly decreased sperm fertilizing ability. Exposure of sperm suspension to a 200-µM concentration of gossypol caused sperm immobilization and a consequent lack of fertilization. Effects of gossypol on sperm motility and fertilizing ability were partially reversible when sperm suspensions were transferred to solutions without gossypol. This reversibility was proportional to the gossypol concentration. We observed a significant increase of abnormal embryos produced by the fertilization of spermatozoa pretreated with gossypol. This implies that gossypol could affect the sperm genome. The results indicate a usefulness for yellow perch sperm in studies of gossypol action mechanisms. Results of in vitro experiments suggest a potential for reproductive impairment in fish when using cottonseed-containing diets or organic fertilizers in yellow perch aquaculture. However, these observations should be confirmed in in vivo experiments with yellow perch and other species.

Novel effects of gossypol, a chemical contraceptive in man: mobilization of internal Ca(2+) and activation of external Ca(2+) entry in intact cells

The effect of gossypol on Ca(2+) signaling in Madin Darby canine kidney (MDCK) cells was investigated by using fura-2 as a Ca(2+) probe. Gossypol evoked a rise in cytosolic free Ca(2+) levels ([Ca(2+)](i)) concentration-dependently between 2 and 20 microM. The response was decreased by external Ca(2+) removal. In Ca(2+)-free medium pretreatment with gossypol nearly abolished the [Ca(2+)](i) increase induced by carbonylcyanide m-chlorophenylhydrazone (CCCP), a mitochondrial uncoupler, and thapsigargin, an inhibitor of the endoplasmic reticulum Ca(2+) pump; but pretreatment with CCCP and thapsigargin only partly inhibited gossypol-induced Ca(2+) release. Addition of 3 mM Ca(2+) induced a [Ca(2+)](i) increase after pretreatment with 5 microM gossypol in Ca(2+)-free medium. This Ca(2+) entry was decreased by 25 microM econazole, 50 microM SKF96365 and 40 microM aristolochic acid (a phospholipase A(2) inhibitor). Pretreatment with aristolochic acid inhibited 5 microM gossypol-induced internal Ca(2+) release by 55%, but suppression of phospholipase C with 2 microM 1-(6-((17beta-3-methoxyestra-1,3, 5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione) had no effect. Gossypol (5 microM) also increased [Ca(2+)](i) in human bladder cancer cells and neutrophils. Collectively, we have found that gossypol increased [Ca(2+)](i) in MDCK cells by releasing Ca(2+) from multiple Ca(2+) stores in a manner independent of the production of inositol-1,4,5-trisphosphate, followed by Ca(2+) influx from external space.