Reproductive effects of endosulfan on male offspring of rats exposed during pregnancy and lactation

Abstract

<jats:p> 1 The reproductive effects of endosulfan on the male offspring of rats were examined. Dams were treated orally with 0, 1.5 or 3.0 mg endosulfan/kg from day 15 of pregnancy to postnatal day (PND) 21 of lactation. The male offspring rats were investigated at PND 65 or 140, corresponding to the pubertal and adulthood stage of development. 2 The dose of 3.0 mg endosulfan/kg induced a decrease in maternal body weight during pregnancy, but litter size and mean birth weight were not affected. Similarly, the age at testis descent and preputial separation was not affected on the male offspring. 3 The daily sperm production (610<jats:sup>6</jats:sup>) was permanently decreased in the highest dose group when investigated at puberty and at adulthood. At the lowest dose, however, the daily sperm production was significantly reduced only at puberty. 4 Histologically, the percentage of seminiferous tubules showing complete spermatogenesis was significantly decreased at puberty. This finding may explain the decrease in daily sperm production observed in the endosulfan-exposed male rats. 5 The results of this study show that low doses of endosulfan have no apparent effect on developmental landmarks or on the weight of reproductive and accessory sex organ. Daily sperm production was the most susceptible endpoint in the male offspring exposed to endosulfan during pregnancy and lactation. To further understand the reproductive effects of endosulfan on male rat offspring, additional reproductive and toxicokinetic studies should be carried out to determine the extent of endosulfan exposure in male rat offspring in utero and during lactation. </jats:p>

Effect of endosulfan on male reproductive development.

“…There are reports of testicular toxicity of endosulfan manifested as decreased spermatogenesis and testicular hormone synthesis (steroidogenesis), as evidenced by a decrease in spermatid count in testes and in sperm count in the cauda epididymis and by changes in marker enzymes for testicular steroidogenesis in adult animals (Chitra et al 1999;Singh andPandey 1989, 1990;Sinha et al 1995). These effects were seen at much lower dosages and shorter durations if exposures occurred during the prenatal or prepubertal periods (Dalsenter et al 1999;Sinha et al 1995Sinha et al , 1997Sinha et al , 2001). Singh and Pandey (1990) also reported profound decreases in the levels of plasma LH, FSH, and testosterone associated with decrease in testicular testosterone in pubertal rats exposed to endosulfan for 30 days.…”

“…More recent studies have shown that exposure of pregnant rats to endosulfan at 1 mg/kg/day from day 12 through parturition leads to decreased spermatogenesis in offspring (Sinha et al 2001). Dalsenter et al (1999) reported similar observations at 3 mg/kg/day but not at 1.5 mg/kg/day, and they attributed this to strain variation (Dalsenter et al 2003). Thus, experimental studies suggest that endosulfan can affect the male reproductive system and also that these effects are likely to be greater if exposure occurs during the developmental phase.…”

Endosulfan (Thiodan® EC 35) induced toxico-pathological effects in male Japanese quails (Coturnix japonica)

“…A decrease in spermatogenesis by exposure of rats to endosulfan has been reported (Dalsenter et al, 1999). In male Japanese quails, crowing behaviour is strictly androgen dependent (Chiba & Hosokawa, 2006).…”

Assessment of Pradosia huberi effects on the reproductive system of male rats

“…36,37 However, despite the absence of these effects, the occurrence of significant changes in other more sensitive variables used in reproductive toxicity testing cannot be neglected, such as the assessment of sperm motility, which represents the percentage of motile spermatozoa and the duration of forward movement (intensity of motility) and the dominant lethality performed to detect mutagenic effects of certain substances in males or females by assessing interference of germ cells during spermatogenesis or oogenesis, with the potential to be lethal to the offspring. 18,38,39 Fertility studies through analysis of parameters, such as reproductive indexes, evaluate the result of mating after the pretreatment of at least one sex. The assessment of fertility and pregnancy provides important information about the functional consequences of an agent on the reproductive system.…”