Effects of soy isoflavones on testosterone synthetase in diet-induced obesity male rats

Obesity is a complex metabolic disease, which causes serious impairment to the health of people. This study aimed to determine the influence of different-doses of soy isoflavones (SIF) on testicular morphology, testosterone levels and the expression of genes and proteins related to testosterone synthesis in diet-induced obesity (DIO) male rats. We used high-fat diet (HFD) to establish a DIO male rat model, then obese rats orally received SIF at doses of 0, 50, 250 and 500 mg/kg per day for four weeks. Results revealed that the body weight was obviously increased, and seminiferous tubules were significantly deformed in obese rats compared with that in normal diet fed controls. After SIF treatment, DIO male rats exhibited decreased body weight in a dose-dependent manner, accompanied with significantly alleviated testicular damages, as well as increased testosterone levels and steroidogenic acute regulatory (StAR), cytochrome P450 11A1 (CYP11A1), cytochrome P450 17A1 (CYP17), hydroxysteroid dehydrogenase-3β (HSD3β), and hydroxysteroid dehydrogenase-17β (HSD17β) protein and mRNA levels. In conclusion, SIF could alleviate testicular damages, increase testosterone levels, and upregulate the expression of proteins and genes related to testosterone synthesis in DIO male rats, which would be important for obesity male reproduction treatment.