• Comparison of protective effects of Silymarin and Melatonin against γ-ray-induced testicular damage in the mice
  • Ayoob Rostamzadeh,1,* Ali Asghar Yousefi Diba,2 Reza Ahmadi,3
    1. Medical plants Research Center, Department of Anatomical Sciences, Faculty of Medicine, Shahrekord University of Medical Sciences, Shahrekord, Iran and Department of Anatomical Sciences, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran.
    2. Department of Radiotherapy, Cancer and Radiation Oncology Research Center, Shohadaye Hafte-Tir Hospital, Tehran, Iran.
    3. Clinical Biochemistry Research Center, Basic Health Sciences Institute, Shahrekord University of Medical Sciences, Shahrekord, Iran


  • Introduction: Spermatogenesis is a long-term and complex process in which sperm cells may be susceptible to oxidative stress from exposure to ionizing radiation (IR). Radioprotective compounds have been used before radiation to reduce cell injury and death caused by ionizing radiation The aim of this study was to evaluate the protective effects of silymarin (SIL), and Melatonin (MLT) alone or in combination with each other against γ-ray-induced testicular toxicity in male mice.
  • Methods: A total number of 64 adult, male NMRI mice were randomly divided into eight equal groups: group 1– untreated (control), group 2– exposed to 2 Gy gamma radiation, group 3– treated with silymarin (50 mg/kg), group 4– treated with melatonin (10 mg/kg), groups 5 to 7– treated with silymarin , melatonin and silymarin plus melatonin respectively, one hour before irradiation with 2 Gy, and group 8– treated with silymarin plus melatonin without irradiation. Evaluation of testis histology and sperm parameters such as sperm count and motility were carried out. All statistical analyses were performed using the SPSS version 18 and significance level (P-value) was considered < 0.05.
  • Results: Exposure of animals to 2.0 Gy gamma radiation resulted into significant decrease in testis weight and total sperm count with increasing in the number of abnormal sperm morphology forms compared to control group and other study groups (p<0.05.) Moreover, in group 2 the basal lamina of the seminiferous tubules was irregular and their diameter significantly decreased together with severe epithelial atrophy and vacuolation. In contrast, SIL, MLT and SIL plus MLT pretreatment on 5 , 6 and 7 groups respectively, displayed a significant increase in body weight, tissue weight, testes- body weight ratio , diameter of the tubules and the area of the seminiferous tubules when compared to irradiated group (group 2)(p<0.05).
  • Conclusion: Our findings indicate that SIL and MLT , alone or in combination with each other protected the testis against gamma radiation–induced testicular toxicity via decreasing inflammation, oxidative DNA damage and apoptosis, which ultimately leads restoration of testicular function and the recovery of spermatogenesis. The selected combination of SIL and MLT significantly reduced γ-ray-induced testicular toxicity suggest a possible synergism. Due to the inherent toxicity of synthetic and chemical substances at active concentrations that protect against radioactive substances and ionizing radiation, researchers have focused on natural products and are seeking out the main solution in the active ingredients of medicinal plants. The current study showed silymarin was an inhibitor and potent radioprotector that can promise new therapies. These synergistic effects need to be further confirmed using more studies that may promise new therapies toward clinical applications.
  • Keywords: Radiation protection, Silymarin, Melatonin, histology, Sperm parameters.