Immunomodulatory effect of propolis extract on population of IL-10 and TGF-β expression in CD4+CD25+ regulatory T cells in DMBA-induced breast cancer in female sprague-dawley rats

Introduction: The aim of this study was to investigate the effect of propolis extract to the population of regulatory T cells (CD4+CD25+FoxP3+) expressing IL-10 and TGF-β in vivo (DMBA-induced breast cancer in Female Sprague-Dawley Rats). Materials and Methods: Thirty virgin female Sprague-Dawley rats, aged 45-50 days-old were injected subcutaneously with 2x10 mg of 7.12-dimethylbenz(a)anthracene (DMBA) for one-week intervals. A week later each rat was administered orally with 5 mg DMBA. Ten rats without DMBA served as negative control. To ensure the development of breast cancer before starting treatment, at week 8, five rats that received DMBA and five negative controls were randomly selected and euthanized. Their breast tissues were then dissected for histological analysis by hematoxylineosin staining. Breast ductal cell morphological changes were apparent in DMBA-treated rats. The remaining rats were divided into 5 groups (6 rats per group). Group I served as a negative control, and Groups II-V were animals treated with DMBA, where Group II served as positive control, and Group III, IV, and V were animals treated with ethanolic extract of propolis (EEP) at doses of 50, 100, and 200 mg/kg body weight (BW), respectively, for 4 weeks. The animals were sacrificed by cervical decapitation. Breast and spleen tissues were subjected to histological and flow cytometric analysis respectively. Results: Statistical analysis by linear regression showed a significant decline in the relative number of CD4+CD25+FoxP3+ regulatory T cells expressing IL-10 or TGF-β after treatments with propolis extracts. Conclusion: In summary, propolis may act as immunomodulatory agent that can be useful for curing cancer patients.