Expression of hypoxia induced factor-1alpha and function of epididymis in varicocele: experiment with rats

Abstract

To investigate the expression of hypoxia induced factor-la (HIF-1alpha) and the content of sialic acid and carnitine in the epididymis in varicocele (VC) and to investigate the mechanism of induction of epididymis dysfunction by VC. Forty-five Wistar rats were randomly divided into 3 equal groups: experimental group undergoing decreasing of the diameter of the left renal vein so as to cause VC, control group, and sham operation group. 49 days after the operation the left epididymis samples were collected. Western blotting and immunohistochemistry were used to detect the HIF-1alpha expression. The contents of sialic acid and carnitine were detected. The HIF-1alpha expression level detected by Western blotting of the experimental group was 0.96 +/- 0.65, significantly higher than those of the control group (0.11 +/- 0.08) and sham operation group (0.07 +/- 0.05) (both P < 0.05); and the positive rate of HIF-1alpha detected with immunohistochemistry of the experimental group was 91.67%, significantly higher than those of the control group (16.67%) and sham operation group (21.43%) (both P < 0.01). The contents of sialic acid and carnitine in the epididymis of the experimental group were 6.3 +/- 2.3 and 1.1 +/- 0.3 respectively, both significantly lower than those of the control group (24.7 +/- 4.4 and 2.8 +/- 0.6) and sham operation group (26.1 +/- 4.4 and 3.2 +/- 0.6) (all P < 0.05). The contents of sialic acid and carnitine in the epididymis were significantly negatively correlated with the HIF-1alpha expression (r = -0.649, P = 0.017; r = -0.666, P = 0.013). VC causes epididymal hypoxia and epididymal dysfunction, and hypoxia plays an important role in VC induced epididymal dysfunction.