Effects of Cadmium Chloride Exposure on Testicular Histomorphology and Reproductive Hormone Levels in Male Rats

Cadmium is a heavy metal environmental contaminant increasingly detected in agricultural soils, water sources, and food crops in the Niger Delta and other industrialised regions of Nigeria, creating exposure risks for livestock grazing contaminated land and consuming affected feed. Cadmium is a recognised endocrine disruptor and testicular toxicant that selectively damages testicular vasculature and germinal epithelium. This study investigated the effects of sub-chronic cadmium chloride exposure on testicular histomorphology and reproductive hormone levels in male Wistar rats. Forty rats were allocated to four groups receiving oral cadmium chloride at 0, 1, 2, and 4 mg/kg daily for 28 days. At termination, testicular weight, morphometric measurements, and histopathological examination using haematoxylin and eosin and periodic acid Schiff staining were performed. Serum testosterone, luteinising hormone, follicle stimulating hormone, and oestradiol were measured by ELISA. Sperm count and motility were assessed from cauda epididymis. Testicular weight decreased significantly in the 4 mg/kg group. Histopathological examination revealed progressive germinal epithelial degeneration, reduced tubular diameter, and interstitial oedema at increasing doses. Leydig cell vacuolation was prominent at 4 mg/kg. Serum testosterone and LH were significantly reduced at 2 and 4 mg/kg, while FSH showed a compensatory elevation. Sperm count and progressive motility were significantly impaired in both higher dose groups. These findings establish dose-dependent testicular toxicity of cadmium in a rat model relevant to environmental contamination risks facing Nigerian livestock and wildlife populations. Keywords: cadmium, testicular toxicity, reproductive hormones, endocrine disruption, rats.