Background: Cynodon dactylon L. pers is one of the plants with applied medicinal value. This study aimed to examine the effect of C. dactylon (L.) aqueous extract on catalase enzymatic activity in kidney and liver tissues as well as the changes in testicular tissues of diabetic rats.

Materials and Methods: In this experimental study, 30 adult male rats were divided into five groups (n=6). Control rats were injected with physiological saline and the others were made diabetic by the injection of streptozotocin (STZ 70 mg/kg, i.p.). The third, fourth and fifth diabetic groups were given the oral aqueous extract of C. dactylon at different doses (50, 250 and 500 mg/kg), respectively for 4 weeks. The catalase enzymatic activity in kidney and liver tissues were measured using Aebi method at the end of the treatment. Then the testis slices were stained and examined by electron microscopy.

Results: The activity of catalase enzyme in kidney and liver of diabetic rats treated with the 500 mg/kg extract was increased significantly compared to the untreated diabetic rats (P<0.05). In the untreated diabetic group, coiled seminiferous tubules and the increased interstitial space of lubules were observable in testis. The aqueous extract-treated group, compared to the diabetic one, showed a significant recovery in the tissue parameters.

Conclusion: Aqueous extract of C. dactylon (L.) have beneficial effects on the activity of anti-oxidant enzymes and changes in testicular tissue during the course of diabetes.