Effet de l'hexachlorobenzène sur certains paramètres de la fonction de reproduction mâle chez Meriones unguiculatus

Abstract

Les pesticides organochlorés, considérés comme contaminants environnementaux, sont connus pour induire des perturbations d'un certain nombre de fonctions physiologiques dont la fonction de reproduction. L'impact de l'hexachlorobenzène (HCB) sur la fonction de reproduction mâle chez Meriones unguiculatus a été étudié sur trois lots d'animaux recevant par gavage quotidien 1,6, 4 et 16 mg/kg PC/j pendant 30 j. Sur un plan macroscopique, le HCB entraîne une diminution significative du poids relatif testiculaire, alors que le poids relatif des vésicules séminales ne semble pas être affecté par le traitement. L'étude cytoarchitecturale montre qualitativement une diminution du nombre de spermatozoïdes, suggérant une modification du déroulement de la spermatogenèse et une perturbation de la phase de différentiation particulièrement visible avec la dose la plus forte. L'état de l'activité testiculaire a été estimé par une détermination morphométrique du diamètre des tubes séminifères et par la quantification de l'activité spermatique. Aucune modification significative du diamètre des tubes séminifères n'est observée ; en revanche, l'activité spermatique des testicules des animaux traités avec 16 mg/kg/j est significativement affectée : elle passe de 88 ± 4,89% chez les animaux témoins à 60 ± 3,16%, soit une diminution de l'ordre de 32%. Sur le plan endocrinien, une diminution significative de la testostéronémie est observée chez les animaux des lots II et III (respectivement 0,48 ± 0,08 ng/ml et 0,54 ± 0,07 ng/ml) comparativement à ceux du lot témoin (1,08 ± 0,1 ng/ml), p < 0.01.

Thymol co-administration abrogates hexachlorobenzene-induced reproductive toxicities in male rats

“…53 In the current research, elevated serum levels of FSH and LH in rats exposed to HCB alone revealed an undesirable response from hypothalamus-pituitary-gonadal axis leading to impaired spermatogenesis and the reduction in the serum testosterone level suggests injury to the Leydig cells possibly due to ROS generation 54 resulting to suppression of spermatogenesis and subsequently, testicular dysfunction. Our result agreed with the reports of Elissalde and Clark 42 who reported reduction in serum testosterone levels in male mice fed diets containing approximately 30 mg HCB/kg-day) for 21 days, and Bitri et al 8 The reduction in the serum levels of FSH and LH with simultaneous increase in the testosterone level following concomitant administration of THY to rats suggests protective effect of THY on HCB-induced hormonal disruption and improved spermatogenesis.…”

“…44 The results are comparable to the earlier report. 8 Besides, administration of THY to HCB-treated rats reversed decrease in the body weight, and the epididymal and testicular weights possibly by improving the metabolic processes via its antioxidant properties.…”

“…5,7 Also, significant decrease in male sex hormones, sperm count, motility and viability accompanied by epididymal and testicular histological damage have been reported with HCB. 4,8 These male reproductive disorders could be associated to excessive generation of free reactive oxygen species (ROS), increased lipid peroxidation, inflammation and apoptosis in the testis induced by HCB. 9 Many natural products are currently being investigated for their potential efficacy in alleviating hazardous effects of environmental pollutant exposure.…”

The endocrine disruptor hexachlorobenzene can cause oxidative damage in the testis of mice

“…Our study found the number of spermatogenic cells and the thickness of the seminiferous tubules decreased, while the area of the lumen in seminiferous tubules increased significantly following the administration of HCB, thus suggesting that HCB caused injury and apoptosis in spermatogenic cells, thereby affecting the normal production of spermatozoa and the normal physiological functions of the testis. In a previous study, Bitri et al also observed that after the administration of HCB, sperm count and motility decreased in Meriones unguiculatus (Bitri et al, 2008); these findings are similar to those of the present study. However, this type of injury does not destroy the structure of the seminiferous tubules.…”

“…In a previous study, the function of the prostate gland was damaged after HCB was administered to male rats by intragastric gavage (Ralph et al, 2003). In another study, the researcher observed a reduction in the testicular weight and sperm motility in rats following HCB treatment (Bitri et al, 2008). Shen et al further showed that the incidence of cryptorchidism and hypospadias in Danish men was higher than that in Finnish men; these authors believed that their findings were related to the higher organic chlorine content in Danish milk than in Finnish milk, thus leading to Danish babies being exposed to higher levels of organic chlorine (Shen et al, 2008).…”