Methods: A search using Scopus, PubMed, Web of Science, and Google Scholar databases was conducted on studies that investigated the effects of plant extracts of C. mas and G. officinalis on testicular tissue and sperm indices in diabetic animals. The first part included the investigation of malondialdehyde (MDA) (nmol/mg), rate of catalase antioxidant activity, and superoxide dismutase. In contrast, the results of the second part included total sperm count (×106), total sperm motility (%), and immobility. The mean difference (MD) (95% confidence interval [CI]) was selected to express the effect size.

Results: Out of 154 identified articles, four studies on mice were included in the meta-analysis. The random effect size yielded an overall effect size for MDA (6.96) with a 95% confidence interval [-6.09; 20.00]. The random effect size yielded an overall effect size for SOD of -0.5076 with a 95% confidence interval [-0.62; -0.40]. The random effect size yielded an overall effect size for CAT of -1.68 with a 95% confidence interval [-1.88; -1.47]. Also, a significant decrease in total sperm count showed the random effect size yielded an overall effect size of -24.74 with a 95% confidence interval [-30.73; -18.74]. The random effect size yielded an overall effect size for sperm motility of -26.65 with a 95% confidence interval [-29.54; -23.76]. A significant increase was demonstrated in sperm immobile in diabetic animals compared to the control group. The random effect size yielded an overall effect size for this indicator is 6.5157 with a 95% confidence interval [-1.96; 14.99].

Conclusion: G. officinalis or C. mas extracts have reduced effects on MDA levels and tissue damage and increased antioxidant enzymes in laboratory animals with diabetes.