Protective Effect of Hydroxytyrosol from Phyllanthus emblica Linn Leaves on Testicular Tissue Injury Induced by CS₂ in Mice

Objective: The protective effects of hydroxytyrosol from Phyllanthus emblica Linn leaves (PHT) on CS₂-induced testicular injury in mice were studied. Methods: The experimental mice were randomly divided into control group (distilled water), CS₂ exposure group (50 mg/m³) and PHT intervention groups (450, 150 and 50 mg/kg). The exposure group and intervention group were exposed to static inhalation for 2 hours a day, 5 days a week for 4 weeks. The intervention group received PHT intragastric intervention every day. The exposure group and the control group were perfused with distilled water. After 4 weeks, the testicular organ coefficient, sperm quality, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activity and malondialdehyde (MDA) content in testicular homogenate were tested, and the pathological sections of testis were observed. Western blot was used to detect the expression of apoptosis-related factors in testis. Results: After the intervention, the testicular organ coefficients of mice in the medium and high-dose PHT groups were higher than those in the CS₂ group (P<0.01). There was no statistical difference between high-dose PHT group and control group (P>0.05); The sperm count and sperm motility in each PHT dose group were higher than those in the CS₂ group (P<0.01), but lower than those in the control group (P<0.01). The sperm deformity rate of each PHT dose group was lower than that of CS₂ group (P<0.01), and there was no significant difference between high-dose PHT group and control group (P>0.05). The pathological sections of testis showed that the morphology of testis in each PHT dose group was improved compared with CS₂ group. No significant difference was observed under microscope between the high-dose PHT group and the control group; The expression of oxidative stress and apoptosis related factor protein showed that MDA content in testis of each PHT dose group was lower than that of CS₂ group (P<0.01), and there was no significant difference between high-dose PHT group and control group (P>0.05); The activity of SOD and GSH-Px in testis tissue of each PHT dose group was higher than that of CS₂ group (P<0.05), but lower than that of control group (P<0.01); The expression of Bax and Caspase-3 in testis tissue of each PHT dose group was lower than that of CS₂ group, the expression of Bcl-2 was increased (P<0.01), and there was difference between each PHT dose group and control group (P<0.05). Conclusion: CS₂ can induce oxidative damage of testis in mice, and PHT can antagonize the testicular tissue damage induced by CS₂. The mechanism may be related to the strong antioxidant activity of PHT, which maintains the activity of some antioxidant enzymes, alleviates the oxidative damage and reduces the formation of apoptotic factors.