[Effects of xuebijing injection on cardiac function and structure in rats with myocardial hypoxia/reoxygenation injury].

OBJECTIVE: To investigate the protective effects of xuebijing (XBJ, Traditional Chinese Medicine Complex) injection on cardiac function in rats with myocardial hypoxia/reoxygenation(H/R) injury. METHODS: The isolated langendorff perfused rat heart model was established. One hundred and thirty SD rats were randomly divided into sham group, hypoxia/reoxygenation group, low dose XBJ(XBJL) group, middle dose XBJ(XBJM) group and high dose XBJ(XBJH) group. All groups except sham group were divided into three subgroups according to reoxygenation time(0.5 h,1 h, 2 h) (n=10). In sham group, left ventricular development pressure(LVDP), maximal rates of increase/decrease of the left ventricular pressure(±dp/dtmax), left ventricular pressure (LVP), and heart rates (HR) were recorded after 20 minutes balance perfusion. The creatine kinase-MB (CK-MB) in myocardium was detected by ELISA. In other groups, after 20 minutes balance perfusion, we perfused ThomasⅡto stop the hearts from beating for 30 minutes, then reperfused the K-H until hearts recover beating. The microstructure of myocardium was observed under light microscopy. LVDP, ±dp/dtmax, LVP and HR were continuously recorded in other four groups and the concentrations of CK-MB in myocardium were measured by ELISA at different time points after reoxygenation. Microstructure of myocardium in each group were observed under light microscopy. RESULTS: LVDP, ±dp/dtmax, LVP and HR of other groups were significantly lower than those of sham group(P<0.05). The levels of CK-MB were higher than that of sham group(P<0.05). LVDP, ±dp/dtmax, LVP and HR of XBJL, XBJM and XBJH groups were higher than those of I/R group at corresponding time points after reoxygenation(P<0.05). The levels of CK-MB were lower than that of I/R group(P<0.05) and the cardiac function was improved. The middle dose of XBJ had the best protective effect. CONCLUSIONS: Xuebijing injection can effectively improve cardiac function and structure in rats with myocardial hypoxia/reoxygenation injury, and middle dose of XBJ is the best.

[Nrf2/ARE pathway mediates the reducing effect of Dexmedeto-midine on ischemia/reperfusion injury in skeletal muscle].

OBJECTIVE: To explore the role of Nrf2/ARE pathway in skeletal muscle ischemia/reperfusion(I/R) injury preconditioning by dexmedetomidine(DEX). METHODS: Twenty-eight SD rats were randomly divided into sham-operated(Sham group)、I/R group、I/R+ DEX(DEX group) and I/R+DEX +Atipamezole (Atip group). In the Atip group, Atip(250 µg/kg) and DEX(25 µg/kg) were injected together after anesthesia; In the Sham and I/R groups, the homologous saline was also injected at the same time; In the DEX group, the homologous DEX and saline were coinjected. After 30 minutes, the hind limb ischemia was induced by clamping the common femoral artery and ligaturing collateral circulation. After 3 h of ischemia, the clamp and tourniquet were removed and the rats underwent 2 h of reperfusion. We measured plasma concentrations of lactate dehydrogenase (LDH) and creatine kinase(CK). The gastrocnemius muscle was harvested and immediately stored at -80℃ for the assessment of malondialdehyde(MDA)、superoxide dismutase(SOD) and Nrf2/HO-1 protein detected by Western blot. The other section muscle was stored in triformol for immunohistochemical and HE staining. The wet/dry was also immediately detecting. RESULTS: The levels of wet/dry、MDA、LDH、CK、Nrf2 and HO-1 were higher(P<0.05) while the level of SOD was lower(P<0.05) in the I/R group than those in sham group. The levels of wet/dry、MDA、LDH、CK were significantly lower(P<0.05) yet the levels of SOD and Nrf2/HO-1 were significantly higher(P<0.05) in DEX group than those in I/R group. However, Atip reversed the effect of DEX in Atip group, each of indicators had significant changes compared with those in the DEX group(P<0.05). CONCLUSIONS: Nrf2 protein was expressed in skeletal muscle of rat and DEX could promote its level in nucleus by α-adrenergic receptor. The down-stream products of Nrf2 have the effect of antioxidant.