Evidence-based mechanistic role of chrysin towards protection of cardiac hypertrophy and fibrosis in rats

Cardiac hypertrophy is the enlargement of cardiomyocytes in response to persistent release of catecholamine which further leads to cardiac fibrosis. Chrysin, flavonoid from honey, is well known for its multifarious properties like antioxidant, anti-inflammatory, anti-fibrotic and antiapoptotic. To investigate the cardioprotective potential of chrysin against isoproterenol (ISO), cardiac hypertrophy and fibrosis are induced in rats. Acclimatised male albino Wistar rats were divided into seven groups (n 6): normal (carboxymethyl cellulose at 0.5 % p.o.; as vehicle), hypertrophy control (ISO 3 mg/kg, s.c.), CHY15 + H, CHY30 + H & CHY60 + H (chrysin; p.o.15, 30 and 60 mg/kg respectively thorn ISO at 3 mg/kg, s.c.), CHY60 (chrysin 60 mg/kg in per se) and LST + H (losartan 10 mg/kg p.o. thorn ISO 3 mg/kg, s.c.) were treated for 28 d. After the dosing schedule on day 29, haemodynamic parameters were recorded, after that blood and heart were excised for biochemical, histological, ultra-structural and molecular evaluations. ISO administration significantly increases heart weight:body weight ratio, pro-oxidants, inflammatory and cardiac injury markers. Further, histopathological, ultra-structural and molecular studies confirmed deteriorative changes due to ISO administration. Pre-treatment with chrysin of 60 mg/kg reversed the ISO-induced damage to myocardium and prevent cardiac hypertrophy and fibrosis through various anti-inflammatory, anti-apoptotic, antioxidant and anti-fibrotic pathways. Data demonstrated that chrysin attenuated myocardial hypertrophy and prevented fibrosis via activation of transforming growth factor-beta (TGF-beta)/Smad signalling pathway.