Effect of Omega-3 on Rat Sperm DNA Methylation and Histological Structure of Testis after Treatment with Bleomycin, Etoposide and Cisplatin (BEP)

During the cancer treatment course, in addition to the destructive effects on the tumor cells, chemotherapy also damages healthy tissues and disrupts the balance of oxidant and antioxidant levels. The present study was conducted to evaluate the effect of omega-3 on sperm DNA methylation and histological structure of rat testis after treatment with combination chemotherapy using bleomycin, etoposide and cisplatin (BEP).

In this experimental study, 40 male rats were randomly divided into four groups of control, BEP, BEP+omega-3 and omega-3 (n=10). The control group was treated with 0.9% normal saline intraperitoneally for 18 weeks. The second group (BEP) first received 0.9% normal saline intraperitoneally for nine weeks. Then, it received BEP at 5.1 mg / kg for nine weeks, received etoposide and cisplatin at 5.7 mg/kg through gavage on days 1-5 of each week, and then received bleomycin at 75 mg/kg on days 2 of each week. The third group was gavaged with 0.9% saline for 9 weeks and then, orally received 300 mg/kg/day omega-3(capsule containing 1000 mg, 18% EPA and 12% DHA) for 9 weeks and in BEP + omega-3 group treated with BEP based on the same method and then orally received 300 mg/kg omega-3 as an antioxidant for the second nine weeks daily. Sperm DNA methylation and histological structure of rat testis including seminiferous tubules and basement membrane thickness were respectively evaluated by immunofluorescence staining and Periodic acid – Schiff (PAS) after 18 weeks of treatment in all groups.  

The mean percentage of sperm DNA methylation in the BEP-treated group (52.22±3.11) was significantly decreased compared to the control group (81.80±2.92) (p<0.001). However, the mean percentage of sperm DNA methylation increased significantly with omega-3 use after treatment with BEP (67±2.18) compared with BEP group (p<0.01). In light microscopy of testicular tissue, the number of spermatogonial cells (44.95±1.56), primary spermatocytes (47.60±1.45) as well as the epithelial thickness of seminiferous tubules (145.5±5.64) and basement membrane (7.07±0.29) decreased in the BEP-treated group in comparison with control group (p<0.001). However, the use of omega-3 after treatment with BEP significantly improved the number of germ cells and epithelial thickness of the seminiferous tubule and basement membrane (p<0.01).

Based on the results of this study, omega-3 as an antioxidant can improve the cytotoxic effects of chemotherapy drugs and it is recommended to be used for cancer patients after chemotherapy to reduce the cytotoxicity of these drugs.