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

Abstract

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 ± 2o
C three times a day for 2 weeks. Control animals received 
same treatment in water of normal temperature (23 ± 2o
C). 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.