Exploration des effets cytotoxiques du plomb sur la fonction sexuelle endocrine et exocrine chez le rat pubère mâle et femelle. Mise en évidence d’une action apoptotique

Abstract

Impact of lead given in drinking water on the endocrine and exocrine sexual activity in pubescent rats. Determination of an apoptotic process. This study deals with the impact of chronic exposure to lead on male and female fertility in rats. Male and female rats (3 months old) were fed on commercial tablets (SICO, Sfax). For drinking, some rats were given distilled water (T = controls), the other ones were given distilled water enriched with lead acetate, either 3 (P1 group) or 6 mg ml -1 (P2 group), for 15, 30, 45, 60 or 90 days. In male rats, absolute and relative weights of testis, epididym, prostate and seminal vesicles were found to significantly decrease at day 15 in the P2 group and at day 45 in the P1 group. However, at day 60, these absolute and relative weights returned to control values. Lead-induced pathological changes in spermatogenesis were observed at day 15 by histological study: arrest of cell germ maturation, changes in the Sertoli cells, and presence of apoptotic cells revealed by borated toluidine blue in the testis. Presence of lead deposits was observed after histochemical staining using sodium rhodizonate. Serum testosterone level was found to be lowered at day 15 in both (P1) and (P2) groups, to display a peak at day 60, then to return to controls values, in spite of the continuation of the treatment. In female rats, absolute and relative weights of ovary and uterus were found unchanged. The vaginal smears practised in females revealed the oestrus phase in all groups. Exposed females were mated with control males, and fecundity was assessed 15 days later by counting the number of pregnancies and the number of conspectuses per pregnancy. Fertility was found to be reduced in females of P1 and P2 groups as compared to control females (T group). Lead level in blood was found to be poorly correlated with the level of poisoning, whereas lead accumulation in tail was found to be dose-dependent. Therefore, lead accumulation in tail appears as a more reliable biomarker of exposure to lead. In summary, our study shows that chronic exposure to lead causes a double sexual disorder in rats: first, disorder deals with the hormonal function, which is affected at the early stages of poisoning, but is rapidly corrected; second, disorder deals with the genital tract, affecting the testis and the ovary, resulting in a reduced fertility in both P1 and P2 females, in spite of the presence of a normal oestrus. The cytotoxic effect of lead in males seems to be related to an apoptotic process.

Early-Life Lead Exposure Results in Dose- and Sex-Specific Effects on Weight and Epigenetic Gene Regulation in Weanling Mice

“…Among animals, Pb is believed to act on the hypothalamic–pituitary–gonadal axis by blocking the release of GnRH, thus decreasing puberty-related hormones such as LH, IGF-1 and estradiol [37–41]. At the gonadal steroid biosynthesis level, Pb has been shown to impair Leydig cell and Sertoli cell functions [42, 43]. Our measurement here was limited to overall weanling bodyweight rather than in changes in fat and lean body mass.…”

Clomiphene citrate ameliorated lead acetate-induced reproductive toxicity in male Wistar rats

“…It may be present as a pollutant in different sources such as contaminated food, lead water pipes, unsanitary food preservation, industrial pollution, road traffic, paint, cosmetics, and drinking water (López-Carrillo et al, 1996). It has been well documented that lead impairs the reproductive function of experimental animals and humans through endocrine disruption (Biswas & Ghosh, 2004; Hernández-Ochoa et al, 2005; Jackie et al, 2011) and depletion of antioxidant reserves (Gorbel et al., 2002; Elgawish & Abdelrazek, 2014).…”

Aqueous Extract of Allium sativum (Linn.) Bulbs Ameliorated Pituitary-Testicular Injury and Dysfunction in Wistar Rats with Pb-Induced Reproductive Disturbances

“…Its prolonged persistence in the environment results from its non-biodegradable nature [ 4 , 5 ], thus making it a potent environmental and occupational toxin. It is reputed for its wide range of toxic physiological, biochemical and histological effects on the brain [ 6 ], kidney [ 7 ], liver [ 8 ], blood [ 9 ], the endocrine system [ 10 ] and testis [ 11 , 12 ] of exposed subjects. The Pb-induced oxidative stress in tissues, which leads to oxidative damage, is known to follow two pathways; first is the generation of reactive oxygen species (ROS) while the second pathway is the depletion of antioxidants reserve through the generation of ROS [ 13 , 14 ].…”