Inhibitive effects of quinestrol on male testes in Mongolian gerbils (Meriones unguiculatus)

Antifertility effects of quinestrol in male lesser bandicoot rat, Bandicota bengalensis, and potential in managing rodent population under field conditions

Integrating fertility control techniques using steroid hormones after lethal control can help reduce post control rebuildup of rodent populations. The current study is the first to assess the antifertility effects of quinestrol in male lesser bandicoot rat, Bandicota bengalensis which is the predominant rodent pest species in Southeast Asia. Rats in different groups were fed bait containing 0.00%, 0.01%, 0.02%, and 0.03% quinestrol for 10 days in laboratory and evaluated immediately, and 15, 30, and 60 days after treatment discontinuation for effect on reproduction and other antifertility parameters. Effect of 0.03% quinestrol treatment for 15 days was also observed in managing rodent populations in groundnut crop fields. Treatment resulted in average consumption of 19.53 ± 1.80, 67.63 ± 5.50, and 246.67 ± 1.78 mg/kg bwt active ingredient by three treated groups of rats, respectively. No reproduction was observed in female rats mated with male rats treated with 0.03% quinestrol, even 30 days after cessation of treatment. Post-mortem examination showed a significant (P < 0.0001) effect of treatment on organ weights (testis, cauda epididymis, seminal vesicles, and prostate gland) and different sperm parameters (sperm motility, sperm viability, sperm count, and sperm abnormality) in the cauda epididymal fluid with partial reversibility after 60 days. A significant (P < 0.0001) effect of quinestrol on the histomorphology of testis and cauda epididymis was observed, suggesting its effect on spermatogenesis. Affected cell association and cell count in seminiferous tubules did not fully recover within 60 days of stopping treatment. Evaluation of the effects of quinestrol treatment in groundnut fields showed greater reductions in rodent activity in fields treated with 2% zinc phosphide followed by 0.03% quinestrol treatment as compared to fields treated with 2% zinc phosphide alone. Research concludes that quinestrol has the potential to reduce fecundity and post control rebuildup of B. bengalensis populations, but long-term studies of the effectiveness of quinestrol under large-scale field conditions are needed to use it as part of an integrated pest control program for rodents.

The Mongolian Gerbil as a Useful Experimental Model in Reproductive Biology

Ultimately, the Mongolian gerbils (Meriones unguiculatus) have acquired a relevant role in biological and biomedical experiments alongside other rodents. The use of gerbils in research has been mainly oriented to physiological and pharmacological studies, with special attention to nervous, digestive, and auditory systems as well as microbiology and parasitology. Ultimately, gerbils have also been applied for studying carcinogenesis in different organs and systems, since these animals show a natural propensity to develop spontaneous proliferative lesions, especially in steroid-responsive organs. This characteristic shed light on the reproductive aspects of this rodent model regarding morphological features in male and female individuals. This review of literature summarizes the significance of this model as an alternative to the use of inbred mice and rats in reproductive experimental research, highlighting recent findings. Gerbils have contributed to the expansion of knowledge in prostate biology in male and female individuals, providing studies related to prostatic morphogenesis and neoplasia. In the testes, spermiogenesis occurs in 15 steps, differently from other experimental models. Also, the complete maturation of the testis-epididymal complex occurs between the second and third months. Mammary gland alterations related to the estrous cycle and pregnancy were described, as well as its modulation under endogenous and exogenous estrogenic compounds. The ovaries frequently present ovarian cysts. Furthermore, this organ shows predominantly interstitial steroidogenic glands in the stroma, especially at aging. Adrenal gland shows a large size compared to other animals, presenting three distinct zones with a remarkable role in steroidogenesis.

Effect of quinestrol on body weight, vital organs, biochemicals and genotoxicity in adult male lesser bandicoot rat, Bandicota bengalensis

The present study was aimed to evaluate the toxic effects of quinestrol (a synthetic estradiol) in male lesser bandicoot rat, Bandicota bengalensis. Effect was studied on body weight, weight of vital organs, changes in level of biochemical parameters and genotoxicity. Feeding of bait containing 0.01% quinestrol in bi-choice and 0.02 and 0.03% quinestrol in no-choice for a period of 10 days resulted in total ingestion of 19.50, 67.60 and 243.30 mg/kg bwt, respectively of the active ingredient. Autopsy of rats after 15 and 30 days of treatment withdrawal revealed no significant effect on body weight and weights of vital organs of rats. A significant decrease in the testicular levels of 17-beta hydroxysteroid dehydrogenase and increase in total soluble proteins was observed in rats treated with 0.02 and 0.03% quinestrol. The plasma levels of lipid peroxidation in the form of malondialdehyde concentration and lactate dehydrogenase increased significantly whereas the level of testosterone decreased significantly in treated rats. The plasma levels of acid and alkaline phosphatases, superoxide dismutase and total proteins differed non-significantly among rats of treated and untreated groups. The effect was found reversed partially in rats autopsied after 60 days of treatment withdrawal. No micronuclei in bone marrow cells, no aberrations in chromosomes and no DNA damage in blood cells during comet assay indicated no genotoxic effect of quinestrol on B. bengalensis at the test doses administered. The results thus revealed that quinestrol causes reversible toxic effects in the form of oxidative stress, increased lytic enzyme activity and decreased steroidogenesis which may further lead to testicular damage thereby inhibiting reproductive function. Also more effect was shown at higher doses ingested in no-choice test as compared to low doses ingested in bi-choice tests.

Quinestrol induces spermatogenic apoptosis in vivo via increasing pro-apoptotic proteins in adult male mice

The effects of quinestrol on spermatogenesis were investigated in adult male mice by daily intragastric administration of quinestrol with various doses of 5, 10, 50 and 100mg/kg body weight for 10 days. The sperm counts declined while the number of abnormal spermatozoa went up in mice treated with quinestrol. The testicular weight and seminiferous tubular area gradually declined with increasing dosages of quinestrol to 50 and 100mg/kg. Rarefied germ cells showed irregular distributions in the seminiferous tubules of mice treated with 50 and 100mg/kg quinestrol. Apoptosis was highly pronounced in spermatogonia, spermatocytes, spermatids and Leydig cells. Antioxidant enzyme activities - superoxide dismutase and glutathione peroxidase - as well as total antioxidant capacity significantly reduced, while malondialdehyde contents increased. The number of germ cells expressing caspase-3, p53, Bax and FasL significantly increased whereas cells expressing Bcl-2 significantly decreased in groups treated with 50 and 100mg/kg quinestrol compared with the control. The concentration of nitrogen monoxidum also increased significantly under these dosages. The results suggest that quinestrol stimulates oxidative stress to induce apoptosis in spermatogenic cells through the mitochondrial and death receptor pathways in adult male mice.

Protective Effects of Lycium barbarum Polysaccharides on Testis Spermatogenic Injury Induced by Bisphenol A in Mice

To observe the effects of Lycium barbarum polysaccharides (LBP) on testis spermatogenic injuries induced by Bisphenol A (BPA) in mice. BPA was subcutaneously injected into mice at a dose of 20 mg/kg body weight (BW) for 7 consecutive days. LBP was administered simultaneously with BPA by gavage daily at the dose of 50, 100, and 200 mg/kg BW for 7 days. After treatment, the weight and the histopathology changes of testis and epididymis were examined; the contents of T, LH, GnRH, antioxidant enzyme, and malondialdehyde (MDA) in serum were detected; proapoptotic protein Bax and antiapoptotic protein Bcl-2 were also detected by immunohistochemical method. Results showed that the weights of testis and epididymis were all increased after supplement with different dosages of LBP compared with BPA group, and the activities of SOD and GSH-Px were significantly increased in LBP groups, while MDA contents were gradually decreased. Moreover, the levels of T, LH, and GnRH were significantly elevated in serum treated with 100 mg/kg LBP. LBP also shows significant positive effects on the expression of Bcl-2/Bax in BPA treated mice. It is concluded that LBP may be one of the potential ingredients protecting the adult male animals from BPA induced reproductive damage.