Effects of lindane on cleaved caspase-3 expression in spermatogenic cells and serum luteinizing hormone and testosterone concentrations in rats

Background Lindane is the gamma isomer of organochlorine pesticide hexachlorocyclohexane and can damage male reproductive system.

Objective This experiment investigates the effects of sub-chronic exposure to lindane on cleaved caspase-3 expression in testicular tissues and serum luteinizing hormone and testosterone concentrations in male rats, aiming to explore the mechanism of lindane-induced male reproductive damage.

Methods Forty male SD rats were randomly divided into five groups:solvent control group (10mg·kg^-1 corn oil), positive control group (100 μg·kg^-1 estradiol), and 3, 6, and 13mg·kg^-1 lindane groups. The rats were treated with the designed dosages by gavage once a day for continuously eight weeks. After 24 h of last exposure, the rats were weighed, and after an overnight fasting, the rats were anesthetized with 10% chloral hydrate and dissected to determine the cleaved caspase-3 protein expression in spermatogenic cells and serum luteinizing hormone and testosterone concentrations.

Results Compared with the solvent control group, there was no significant difference in body weight of rats in the exposure groups (P>0.05); the sperm density of rats in the 13 mg·kg^-1 group decreased (P < 0.05); the sperm survival rate decreased and the cleaved caspase-3 protein expression level in spermatogenic cells were upregulated in the 6 mg·kg^-1 and 13 mg·kg^-1 groups (P < 0.05); the serum luteinizing hormone concentration increased and the serum testosterone concentration decreased in the 13 mg·kg^-1 group (P < 0.05). Compared with the positive control group, there were no significant differences in body weight and sperm density in the exposure groups (P>0.05); the sperm survival rate increased, the protein expression level of cleaved caspase-3 in spermatogenic cells decreased, and the serum luteinizing hormone concentration decreased in the 3 mg·kg^-1 and 6 mg·kg^-1 groups (P < 0.05); the serum testosterone concentration in each exposure group increased (P < 0.05). The testicular pathological observations showed that the rats in each lindane-treated group presented varying degrees of testicular damage, including increased seminiferous tubule space, disarranged spermatogenic cells, and decreased sperm counts; the rats in the positive control group also showed enlarged seminiferous tubule space, reduced sperm counts, and spermatogenic cells in the lumen.

Conclusion Lindane may regulate spermatogenic cell apoptosis by upregulating the cleaved caspase-3 protein expression in testicular tissues, leading to decreased serum testosterone level and spermatogenesis in rats. Under these experimental conditions, lindane may cause less endocrine disruption in rats than estradiol.