ABSTRACT
ObjectiveTo investigate the effects of hydroxycamptothecin liposomes （LHCPT） on myocardial fibrosis in rats with heart failure by regulating the sphingosine kinase 1 （SphK1）/sphingosine-1-phosphate （S1P） signaling pathway. MethodsSD rats were divided into control group， model group， hydroxycamptothecin （HCPT） group， LHCPT group， captopril group， and LHCPT+K6PC-5 （SphK1 activator） group， with 12 rats in each group. The heart failure rat models in all groups except the control group were established by intraperitoneal injection of doxorubicin and then the corresponding drugs were given once a day. After four weeks， we applied color Doppler ultrasound to detect left ventricular end systolic diameter （LVESD）， left ventricular end diastolic diameter （LVEDD）， and left ventricular ejection fraction （LVEF） in rats； HE and Masson staining for myocardial pathological damage and myocardial fibrosis in rats， respectively； ELISA method for the levels of tumor necrosis factor-α （TNF-α） and interleukin-6 （IL-6） in rat myocardial tissues； qRT-PCR for the expression of transforming growth factor-β1 （TGF-β1）， type I collagen （Collagen I）， and type Ⅲ collagen （Collagen Ⅲ） in rat myocardial tissues； Western blot for the expression of SphK1 and S1P proteins in rat myocardial tissues. ResultsCompared with the control group， the model group showed severe myocardial pathological damage and myocardial fibrosis， increased LVESD， LVEDD， levels of TNF-α and IL-6， expression of TGF-β1， Collagen I， Collagen Ⅲ， SphK1， S1P and decreased LVEF （P<0.05）. Compared with the model group， the HCPT group， LHCPT group and captopril group showed alleviated myocardial pathological damage and myocardial fibrosis， decreased LVESD， LVEDD， levels of TNF-α and IL-6， expression of TGF-β1， Collagen I， Collagen Ⅲ， SphK1， S1P and increased LVEF （P<0.05）. Compared with the LHCPT group， the LHCPT+K6PC-5 group showed aggravated myocardial pathological damage and myocardial fibrosis， increased LVESD， LVEDD， levels of TNF-α and IL-6， expression of TGF-β1， Collagen I， Collagen Ⅲ， SphK1， S1P and decreased LVEF （P<0.05）. ConclusionLHCPT may inhibit myocardial fibrosis in heart failure rats by inhibiting the SphK1/S1P signaling pathway.