Introduction: Cadmium, as an environmental pollutant, exerts its destructive effects on male reproductive system and sperm by inducing oxidative stress. silymarin, an effective substance extracted from silybummarianum, is a potent antioxidant which inhibits oxidative stress. the aim of this study was to investigate if silymarin can inhibit the harmful effects of cadmium on plasma membrane and DNA integrity of human spermatozoa. Methods: Human spermatozoa were divided into five groups: 1. spermatozoa at 0 hour 2. control group 3. spermatozoa treated with cadmium chloride (20µm) 4. spermatozoa treated with silymarin (2µm) + cadmium (20µm) 5. spermatozoa treated with silymarin (2µm). spermatozoa from groups 2-5 were incubated at 37°c for 180 minutes. the hypo-osmotic swelling test evaluated the functional integrity of the sperm plasma membrane. DNA fragmentation was performed by sperm chromatin dispersion test, whereas acridine orange staining was used to test the denaturation of sperm DNA. Results: In the cadmium chloride group a significant decrease was found in the plasma membrane integrity, whereas Dna fragmentation was significantly increased compared to the control group. in the cadmium + silymarin group, silymarin could significantly compensate these effects compared to the cadmium chloride group. in addition, cadmium chloride had no effect on sperm denaturation as compared to the control group. Conclusion: Cadmium chloride induces adverse effects on plasma membrane and DNA integrity of human sperm and silymarin as a potent antioxidant could compensate these effects.
