Serum 25OHD3 of Obese Mice Is Affected by Liver Injury and Correlates with Testosterone Levels and Sperm Motility

Abstract

<b><i>Introduction:</i></b> The concentration of 25-hydroxycholecalciferol (25OHD₃) in the serum of obese people is low and often accompanied by symptoms of low fertility. Therefore, vitamin D is recommended as a potential treatment option. However, after clinical trials, it was found that vitamin D cannot effectively increase the concentration of 25OHD₃ in the serum of obese people. How obesity causes low 25OHD₃ concentration and low fertility is unclear. <b><i>Methods:</i></b> We analyzed the physiological and pathological changes in obese mice induced by a high-fat diet (HFD) and the changes in mice after supplementing with 25OHD₃. <b><i>Results:</i></b> The concentration of 25OHD₃ in the serum of obese mice induced by HFD was significantly reduced, and these mice showed liver hypertrophy accompanied by abnormal liver injury, testicular hypertrophy, low testosterone levels, high leptin levels, and low sperm motility. The mRNA and protein expression of CYP2R1 of hydroxylated vitamin D₃ was significantly reduced; CYP11A1 and CYP11A2, which synthesize testosterone, were significantly reduced. After supplementing with 25OHD₃, there was an increase in serum 25OHD₃ concentration, testosterone level, and sperm motility, but it cannot improve the degree of obesity, CYP2R1 expression, and liver damage. <b><i>Conclusion:</i></b> Our research shows that there is a metabolic interference mediated by 25OHD₃ and testosterone between obesity and low sperm motility. The results of this study can provide a scientific basis for studying the mechanism of 25OHD₃ and hormone regulation and treating obese people with low sperm motility.