Punicalagin and captopril mitigate the fibrogenic CD68+ macrophages through TGF-β1 and PPAR-γ signaling pathways in non-ischemic reactive myocardial fibrosis: a bioinformatic and in vivo experiment

Background Non-ischemic reactive myocardial fibrosis (MF) is a significant global cause of chronic heart failure (CHF) related to fatalities and morbidity. Punicalagin (PUN), a primary phenolic component in pomegranate, has been acknowledged as cardioprotective agent in isoproterenol (ISO)-induced ischemic MF. However, the therapeutic roles of PUN individually and in combination with captopril in ameliorating the progression of reactive myocardial fibrosis were not previously explored. Aim of the study Our study was designed to explore the potential therapeutic benefits of PUN alone and in combination with captopril (CAP) in ISO-induced reactive MF. Material and methods Thirty-five male rats of the Sprague–Dawley species, 220–240 g, were randomly allocated across the 5 groups. Group1: Normal control; ISO Group2: received single daily subcutaneous injections of isoprenaline (5 mg/kg/day) for 10 days Captopril (CAP) group3: orally administered in a dose of 15 mg/kg/day for 60 days; PUN group4: orally administered in a dose of 200 mg/kg/day60 days, and CAP/PUN group5: rats were administered both CAP and PUN in the aforementioned doses and duration. Results Bioinformatically, CD68 protein showed co-expressional associations with TGF-β1, PPAR-γ, and Akt proteins, for which PUN displayed significant affinities via molecular docking. In ISO-injected rats, PUN and/or CAP lowered abnormally elevated parameters, but the combination therapy demonstrated superior effects in near normalizing most parameters including cardiac hemodynamics (in contrast to ISO group, HR, SBP, DBP, and DBP were by 53%, 21%, and 39%, respectively, with concomitant increase in EF by 70% and decrease in IVSD and LVDD by 43% and 66%, respectively, alongside with amelioration of the ISO-driven higher cardiac TGF-β1, Smad2/3, PTEN, and Wnt/β-catenin levels by 57%, 74%, 69%, 70% and 67%, respectively, in addition to considerable 1.6-, 1.2-, onefold, 1.45-fold increases in cardiac PPAR-γ, PI3K, p AKT, and Smad7 expression levels, respectively). Histopathological MF generated by ISO was reversed after PUN and/or CAP administration. The immunohistochemical study of fibrotic heart tissues revealed a noticeable increase in CD68 + macrophages and TGF-β1, which were reduced after PUN and/or CAP. Conclusion Phenotypical CD68 + macrophages have a pathophysiological role in ISO-induced reactive MF. Besides, punicalagin alone or in combination with captopril plays complementary therapeutic functions in experimentally reactive MF, suggesting their combination as a potential novel therapeutic approach for MF.