RESUMO
This study investigated the changes in the prostate of high-fat diet (HFD)-fed mice with insulin resistance (IR) and explored the possible mechanisms of the effects of 8-week treadmill aerobic exercise on prostatic hyperplasia in insulin-resistant mice through the IGF-1/IGF-1R/ERK/AKT signalling pathway. Results showed IR in mice caused an increase in prostate-related indicators, such as prostate weight (PW) and prostate volume (PV), resulting in prostatic hyperplasia. The area of the glandular lumen and the height of the glandular epithelium in mice with IR were increased, which indicating that it caused prostatic hyperplasia through epithelial cell proliferation. In addition, the level of IGF-1 in serum and the expression of IGF-1R, ERK and AKT in prostate tissue of high-fat diet induced IR mice increased significantly, which might be related to the proliferation of prostate cells. However, aerobic exercise lowered the blood sugar, serum insulin and IGF-1; inhibited the combination of IGF-1 and IGF-1R on the prostate; down-regulated the expression of IGF-1R, ERK and AKT proteins; and then suppressed the expression of downstream proliferation genes, thereby achieving the purpose of inhibiting the proliferation of prostate epithelial cells. In conclusion. Eight weeks of aerobic exercise might improve the prostate hyperplasia in mice via down-regulating the serum insulin and IGF-1, thus enhancing the insulin sensitivity of insulin-resistant mice and regulating the IGF-1/IGF-1R/ERK/AKT signalling pathway by inhibiting the expression of IGF-1R, ERK and AKT in the prostate tissue. However, this exercise had no significant effect on PV, PW and prostate index (PI).
