L-alanyl-glutamine dipeptide pretreatment attenuates ischemia-reperfusion injury in rat testis.

Purpose: To investigate the effect of alanyl-glutamine dipeptide (L-Ala-Gln) pre-treatment on ischemia-reperfusion (I/R) injury after unilateral testicular torsion-detorsion in a comparative controlled experiment.

Methods: Forty-eight rats (150-200 g) randomly distributed into 4 groups (n=12), and distributed in 2 subgroups (n=6) each, were treated with saline 2.0 ml (G-1, G-3) or L-Ala-Gln 20%, 0.75g/kg dissolved in saline (total volume 2.0 ml) administered in the left saphenous vein 30 minutes before ischemia. Anesthetized rats were subjected to I/R induced by torsion (720°) of the right spermatic cord lasting 1h (G-1, G-2) or 3 hours (G-3, G4). Anesthesia was again applied at the end of ischemia time (T-0) for testis detorsion and 6 hours later (T-6) for orchiectomy. All operations were performed on the right testes through transverse scrotal incisions. Right orchiectomy was carried out at the end of ischemia (T-0), and 6 hours later (T-6) to evaluate the concentrations of malondialdehyde (MDA) and reduced glutathione (GSH) in the testis.

Results: Pretreatment with L-Ala-Gln reduced MDA contents in rat testis at the end of ischemia lasting 3 hours. There was significant increase of GSH levels in T-6 time-point after 1 hour of ischemia. GSH levels also increased in T-0 and T-6 time-points in rats subjected to ischemia for 3 hours.

Conclusion: L-Ala-Gln administered before torsion/detorsion of the spermatic cord decreases lipid peroxidation during ischemia and protects the testis from oxidative stress by upregulating GSH levels during reperfusion.