Effects of Chronic Exposure to Cobalt Chloride on the Fertility and Testes in Mice

Abstract

The effect of twelve weeks ingestion of cobalt chloride (CoCl2) was investigated on the fertility of adult male Swiss mice. Sexually mature male mice were exposed to 200, 400 and 800 ppm cobalt chloride dissolved in drinking water. Based on fluid consumption, exposed animals received an average of 25.66 ± 2.34, 46.91 ± 4.78 and 93.01 ± 6.76 mg/kg/day cobalt chloride, respectively. After the exposure period, these males were mated with untreated female mice. Fertility was significantly reduced in males that ingested cobalt chloride. The number of pregnant females and the number of implantation sites were significantly reduced in females mated with males that had ingested CoCl2 at a concentration of 400 or 800 ppm. The total number of resorptions and the number of females with resorptions were significantly increased in females mated with males that had ingested CoCl2 at all concentrations. On the other hand, the number of viable fetuses was decreased in females impregnated by exposed males at the three concentrations. Absolute epididimal weight, and the relative or absolute testes weights were significantly reduced in males that ingested cobalt chloride at a concentrations of 400 or 800 ppm. In contrast, absolute and relative weights of the seminal vesicles were significantly increased. Furthermor, epididymal and sperm counts and daily sperm production were significantly decreased in males that ingested CoCl2. Histological evaluation of the testes revealed several abnormalities including hypertrophy of the interstitial Leydig cells, congested blood vessels, degeneration of the spermatogonial cells and necrosis of both the seminiferous tubules and the interstitial tissue

Keywords

• CoCl2, Swiss mice, reproductive system