Short-term Scrotal Exposure to Elevated Temperature Prior to Mating Increase Male Ratio at Birth in Sprague-Dawley Rats

This study was carried out to determine the effect of short-term exposure to elevated scrotal temperature at preconception on the testes and offspring sex ratio at birth. Ten adult Sprague-Dawley rats divided into two groups (N=5) were used. The scrota of the treatment group were immersed in a water bath regulated at 33 ± 2̊C three times a day for 2 weeks. Control animals received same treatment in water of normal temperature (23 ± 2̊C). After treatment, each male rat mated with a female rat on proestrous. Following conception, the male rats were sacrificed and testes harvested for histology, hormonal assay, seminal analysis, and antioxidant activities of catalase and superoxide dismutase. The pregnant dams were left to litter and foetal parameters and sex ratio were recorded. Male sex ratio increased in the treated group compared to control. Litter size, crown-rump length and tail length were reduced however; foetal weight was significantly higher in the treated group. Histology showed minimal disintegration of germ cell layers in few tubules and slight destruction of the interstitium and the interstitial cells. Reductions were observed in semen parameters (motility < 0.05), serum levels of FSH, LH, testosterone (p < 0.05) and antioxidant activities of superoxide dismutase and catalase in the treated group compared to the control. Male to female sex ratio increased at birth also, the short term exposure was able to attenuate the deleterious effect on semen parameters, histology and testicular weight, hormonal milieu and antioxidant status observed at long term exposure.

Keywords
Elevated temperature; Sex ratio; Scrotum; foetal parameters; Oxidative stress; Hormonal assay