Expression and significance of miR-210 in the epididymis in rats with varicocele and following varicocelectomy

Abstract

Objective: To investigate the expression of microRNA 210 (miR-210) in the epididymis of rats with varicocele and changes in miR-210 expression following high spermatic vein ligation, so as to explore the significance of the surgery in treating varicocele. Methods: A total of 21 male Sprague-Dawley (SD) rats aged 7 weeks were randomly divided into control group (n=7), experimental group (n=7), and surgical group (n=7). Varicocele model was established in both the experimental and surgical groups, while only vein isolation was performed in the control group. After 8 weeks, spermatic vein diameter were measured in the control and experimental rats, and collected the left epididymis (fixed in formaldehyde and frozen in refrigerator at -80 ℃). In the surgical group, left high spermatic vein ligation was performed, and the left epididymis was collected after 4 weeks as in the control and the experimental groups. The fixed epididymis tissues were treated with HE staining for observation of tissue injuries. The miR-210 expression in the epididymis was detected with reverse transcription-polymerase chain reaction (RT-PCR). At last every group had 5 rats. Results: The pathological examination showed that the number and distribution of mature sperms in epididymal duct in the experimental group were lower and less even compared to the control group, while the two indicators in the surgical group were better than those in the experimental group. The diameter of the left spermatic vein in the experimental group and pre-treatment surgical group were significantly enlarged than in the control group (P<0.01). The expression of miR-210 in the left epididymis in the experimental group was significantly higher compared with the control group(1.32±0.06 vs 0.98±0.14, P<0.01), while the expression of miR-210 in the left epididymis in the surgical group was significantly decreased compared with the experimental group (0.96±0.16 vs 1.32±0.06, P<0.01); the difference between the control group and the surgical group was not statistically significant (P>0.05). Conclusion: The expression of miR-210 in the epididymis may be increased by varicocele and reduced after high ligation of the affected spermatic vein.