Background Tong-xin-luo capsule(TXL),used as a traditional Chinese herb,offeres a therapeutic potential for treatment of cardiovascular diseases.It has been shown to exert a variety of pharmacological effects,including antihypertensiVe effects,and is able to improve ventricular remodeling.However,the mechanisms of its action are not completely understood.The aim of this study was to evaluate the molecular mechanisms of Tong-xin-luo capsule on left ventricular remodeling in spontaneously hypertensive rats (SHR).Methods Sixteen eight-week-old SHRs were randomized into an SHR group(n=8)and a TXL group(n=8)that were given Tong-xin-luo capsule(1.5 mg·kg-1·d-1).Eight Wistar Kyoto(WKY)rats fed with 0.9%NaCl served as the control group(WKY group).Systolic blood pressure(BP),body weight and heart rate were monitored once every two weeks.Ventricular remodeling was detected by hjstopathological examination.Nuclear factor kappa B P65(NF-κB P65)and peroxisome proliferators activated receptor γ(PPAR-γ)protein and phosphorylated inhibitor kappa α(IκBα)protein were detected by immunohistochemistry and western blot respectively.The physical interaction of the P65-P50 heterodimer with IκBα and NF-κB were measured by co-immunoprecipitation.PPAR-Y mRNA,collagen Ⅰ mRNA and collagenⅢ mHNA were measured by real-time PCR.Results TXL inhibited NF-κKB P65 expression and ventricular remodeling and suppressed the activation of NF-κB compared with the SHR group(P＜0.01,P＜0.05).TXL reduced IκBα phosphorylation,increased expression of PPAR-Yprotein and enhanced the physical interaction of the P65-P50 heterodimer with IκBα.The mRNA expression of PPAR-γwas enhanced but the mRNA expression of collagen Ⅰ mRNA and collagen Ⅲ mRNA were suppressed by TXL.Conclusions In spontaneously hypertensive rats,TXL could inhibit ventricular remodeling induced by hypertension,and the inhibitory effect might be associated with the process of TXL increasing the expression of PPAR-γ that could result in the inhibition of the activation of NF-κB.