Effects of melatonin and metformin co-administration on testicular ischemia/reperfusion injury in rats.

INTRODUCTION: Torsion of the spermatic cord is a common urologic emergency among infants and adolescents. It requires early diagnosis and surgical intervention to prevent subfertility and infertility.

OBJECTIVE: The aim of this study was to investigate the effects of melatonin (MEL) and metformin (MET) co-administration on experimental testicular ischemia/reperfusion (I/R) injury in rats.

MATERIAL AND METHODS: Fifty male Wistar rats were randomly divided into five experimental groups (n = 10), as follows. Group 1 was sham operated. In group 2, 1-hour ischemia was induced by the left testicular artery and vein clipping followed by 7 days of reperfusion. In groups 3 and 4, MEL (3 mg/kg) or MET (100 mg/kg) was administered orally for 7 days via oral gavage after ischemia, and in group 5 both agents were co-administered. At the end of trial, the left testis was removed for histological analysis and oxidative stress measurement. Histological findings in seminiferous tubule were evaluated according to Johnsen's scoring system.

RESULTS: I/R reduced superoxide dismutase (SOD) activities and testicular Johnsen's scores accompanied by an elevation in malondialdehyde (MDA) and myeloperoxidase (MPO) levels (p < 0.05). MEL and MET, and their combination restored SOD activity, tissue scores, MDA and MPO levels (p < 0.05). There was no significant difference among individual or combined treatment of these parameters (p > 0.05).

DISCUSSION: In the present experiment, using a rat model it has been demonstrated that testicular I/R caused a significant increase in testicular injuries. This was in accordance with previous studies that have demonstrated the effect of I/R in testicular tissue. Treatment of MEL and MET had a benefit effect, but, there was no significant difference among individual or combined treatment.

CONCLUSIONS: The results of the present study suggest that MEL and MET may be useful for protecting the testes from the I/R injury. However, the combined use of these agents does not further increase the protection from this damage.