Growth plate,the developmental center of endochondral osteogenesis,can be divided morphologically and functionally into a resting zone,a proliferative zone,a prehypertrophic zone and a hypertrophic zone.Injuries to growth plate often lead to bone growth defects including limb length discrepancy and angulation deformity in children.Currently,their orthopedic corrective surgeries are invasive and limitedly effective and no effective biotherapy has been available.Previous studies on animal models of growth plate damage have investigated the related cellular and molecular events in the repair of damaged growth plates in the 4 distinct inflammatory,fibrogenic,osteogenic and remodeling phases.Related molecules involved in the regulation of the above processes,such as inflammatory cytokines tumor necrosis factor alpha,mitogenic platelet-derived growth factor and bone morphogenetic protein,are found to participate in the regulation of growth plate injury.Exploration of the mechanisms may provide new targets for biotherapy.In addition,development of cartilage tissue engineering,especially application of mesenchymal stem cells,also provides potential interventions for growth plate injury.

Objective To investigate the effect and mechanism of Feixin Decoction(Astragali Radix,Pericae Semen,Carthami Flos,Descurainiae Semen Lepidii Semen,Paeoniae Radix Rubra,etc.)on monocrotaline-induced pulmonary arterial hypertension(PAH)rats based on peroxisome proliferator-activated receptor-γ/nuclear factor-κB(PPAR-γ/NF-κB)signaling pathway.Methods Forty-eight male SD rats were randomly divided into normal group,model group,Sildenafil group(0.025 g·kg-1)and low-,medium-and high-dose of Feixin Decoction groups(11.7,23.4,46.8 g·kg-1).PAH rat model was established by single intraperitoneal injection of monocrotaline solution(60 mg·kg-1).After 1 hour of modeling,the rats were given intragastric administration once a day for 28 days.Hemodynamic and echocardiographic parameters including right ventricular systolic pressure(RVSP),mean pulmonary artery pressure(mPAP),right ventricular hypertrophy index(RVHI),pulmonary artery acceleration time(PAAT),pulmonary artery ejection time(PET),tricuspid annular plane systolic excursion(TAPSE),right ventricular internal diameter(RVIDd)and right ventricular anterior wall thickness(RVAWT)were measured in each group.The pathological changes of pulmonary arterioles were observed by HE staining.The expression level of α-smooth muscle actin(α-SMA)in rat pulmonary artery was detected by immunofluorescence.The levels of plasma interleukin-1β(IL-1β),IL-6 and tumor necrosis factor-α(TNF-α)were detected by ELISA.The expression levels of PPAR-γ/NF-κB signaling pathway-related proteins were detected by immunohistochemistry and Western Blot.Results Compared with the normal group,the RVSP,mPAP,RVHI,RVIDd and RVAWT of the model group were significantly increased(P＜0.01).PAAT,PAAT/PET and TAPSE were significantly decreased(P＜0.01).The wall of pulmonary arterioles was significantly thickened,and the percentage of wall thickness of pulmonary arterioles to vascular diameter and the percentage of vascular wall area to total cross-sectional area of pulmonary arterioles were significantly increased(P＜0.01).The positive expression rate of α-SMA protein in pulmonary artery was significantly increased(P＜0.01).The levels of plasma IL-1β,IL-6 and TNF-α were significantly increased(P＜0.01).The positive expression rate of PPAR-γ protein in lung tissue was significantly decreased(P＜0.01),and the positive expression rate of NF-κB protein was significantly increased(P＜0.01).The protein expressions of PPAR-γ and IκB-α in lung tissue were significantly down-regulated(P＜0.01).The protein expression ratio of p-NF-κB/NF-κB was significantly increased(P＜0.01).Compared with the model group,RVSP,mPAP,RVHI,RVIDd and RVAWT in each administration group were significantly decreased(P＜0.05,P＜0.01),while PAAT,PAAT/PET and TAPSE were significantly increased(P＜0.05,P＜0.01).The thickness of the vascular wall was significantly reduced,and the percentage of the wall thickness of the pulmonary arterioles to the diameter of the blood vessels and the percentage of the vascular wall area to the total cross-sectional area of the small arteries were significantly reduced(P＜0.05,P＜0.01).The positive expression rate of α-SMA protein in pulmonary artery was significantly decreased(P＜0.05,P＜0.01).The plasma levels of IL-1β,IL-6 and TNF-α were significantly decreased(P＜0.05,P＜0.01).The positive expression rate of PPAR-γ protein in lung tissue was significantly increased(P＜0.05,P＜0.01),and the positive expression rate of NF-κB protein was significantly decreased(P＜0.05,P＜0.01).The protein expression of PPAR-γ in lung tissue was significantly up-regulated(P＜0.05,P＜0.01),and the protein expression ratio of p-NF-κB/NF-κB was significantly decreased(P＜0.01).The protein expression of IκB-α in the lung tissue of rats in the high-dose group of Feixin Decoction was significantly up-regulated(P＜0.01).Conclusion Feixin Decoction can improve pulmonary artery pressure,right ventricular dysfunction and pulmonary vascular remodeling in PAH rats induced by monocrotaline.The mechanism may be related to the regulation of PPAR-γ/NF-κB signaling pathway to inhibit inflammatory response.