Late reproductive analysis in rat male offspring exposed to nicotine during pregnancy and lactation.

We previously observed that nicotine, administered to rats (Wistar) during pregnancy and lactation periods, provokes, in the progeny, late morphofunctional alterations in Leydig cell, body weight increase in adulthood (90 days post partum, dpp) as well as seminiferous epithelium injury. Aiming to investigate whether the spermatogenic damage previously observed in adult progenies from pregnant and lactating nicotine-exposed rat dams are maintained or whether it is worsened in older rats, we analyzed the morphological testicular alterations after up to two complete periods of spermatogenesis (53 days each), spermatic parameters, and sperm DNA fragmentation. Pregnant and lactating rats were nicotine-exposed (2 mg/kg/day) through an osmotic minipump implanted on the first day of pregnancy and replaced after birth. Absolute Control (no minipump) and Sham Control (minipump without nicotine) groups were established. The offspring were killed at 90, 143, and 196 dpp. Significant alterations in morphometric and stereological testicular parameters, such as concentration of sperm number, daily sperm production, and plasma and intratesticular levels of cholesterol and testosterone were not observed in nicotine-exposed rats. Testicular histopathological analysis showed small intraepithelial vacuolization and an accentuated germ cell desquamation in exposed rats. However, the offspring from nicotine-exposed dams exhibited higher frequency of morphologically abnormal spermatozoa and lower sperm motility in comparison with control groups. In addition, nicotine-exposed groups showed a significant reduction in sperm mitochondrial activity and an increased sperm DNA fragmentation (Comet assay). These results indicate a late reproductive damage in the male progeny caused by maternal nicotine exposure, related to the decrease in sperm quality.

Sexual behaviour, sperm quantity and quality after short-term streptozotocin-induced hyperglycaemia in rats.

Studies of diabetes mellitus in the streptozotocin rat model suggest that sexual dysfunctions may result from diabetes-induced alterations of the neuroendocrine-reproductive tract axis. Our investigation was performed to better define the effects of short-term hyperglycaemia on rat epididymal sperm quantity, quality and transit time, using both natural mating and artificial in utero insemination protocols. Male rats were made diabetic with streptozotocin (sc, 40 mg/kg), whereas controls received vehicle. Sexual behaviour was tested after 15 days and sperm fertilizing ability was checked 22 days after the injection through natural mating and artificial in utero insemination. Other parameters such as daily sperm production, testosterone levels, as well as sperm morphology and motility were also investigated. Fifty per cent of the diabetic animals showed no copulatory behaviour during tests and the number of animals reaching ejaculation was smaller in the diabetic group when compared with the control group (33% vs. 83%). Diabetes resulted in decreased body and reproductive organ weights, as well as diminished sperm counts in the testis and epididymis, that were associated with diminution of plasmatic testosterone levels. After natural mating, there was a decrease in the fertility in the diabetic adult male rats (25.5%) compared with control animals (81.5%). However, distal cauda epididymal sperm from diabetic rats displayed normal fertilization ability (91.5%) using in utero insemination. There were no effects of hyperglycaemia on sperm transit time in the epididymis and on spermatogenesis. Our results indicate that diabetes mellitus produces reproductive dysfunction, but does not compromise sperm fertilizing ability in the cauda epididymis in this experimental model.