Protective effects of silymarin and curcumin on cyclophosphamide-induced cardiotoxicity

Cyclophosphamide (CP) is a potent anticancer agent; its clinical use is limited due to its marked cardiotoxicity.

The present study was aimed at evaluating the cardioprotective effects of silymarin (SLY) and curcumin (CUR), which have strong antioxidant properties, against the toxic effects of high-dose CP on the heart of rats.

A total of 36 adult Wistar albino female rats were randomly divided into six groups. Group I (control group; nothing was administered), Group II (CP group; 30mg/kg/day CP was administered intraperitoneally to each animal for seven days), Group III (SLY group; 100mg/kg/day SLY by gavage for 14 days), Group IV (CUR group; 100mg/kg/day CUR by gavage for 14 days), Group V (SLY+CP group; 100mg/kg/day SLY by gavage for 14days plus 30mg/kg/day CP intraperitoneally starting from the seventh day) and Group VI (CUR+CP group; 100mg/kg/day CUR by gavage for 14days plus 30mg/kg/day CP intraperitoneally starting from the seventh day). Biochemical, histopathological and immunohistochemical methods were utilised for evaluation of the cardiotoxicity.

The result showed that an increase in heart MDA and DNA fragmentation levels were detected while significant decreases were seen in SOD levels in CP alone group when compared to the other groups. CP caused severe damage in the histopathological status of heart tissue including intersititial oedema, haemorrhage, degeneration and necrosis in muscle fibrils and perinuclear vacuolization. A significant increase in the percentage of TUNEL-positive cells and γH2AX protein expression was detected in the CP-treated group compared to the control and other treated groups. There was significant increase in the percentage of caspase 3-positive cells and decrease in the percentage of Bcl-2 positive cells in the CP group compared to the control group and other treated groups. However, a significant decrease in the percentage of cTnI and cTnT immunoreactivity was also observed in the CP-treated group compared to the control and other treated groups. In the groups in which SLY and CUR were administered concurrently with CP, biochemical parameters, histopathological and immunohistochemical results were found to be significantly lower than in the CP-only group.

These results lead to conclusion that the natural antioxidant SLY and CUR might have protective effects against CP-induced cardiotoxicity and oxidative stress in rats.