Effect of Shenfu infusion on myocardial KATP channel in rats after ischemia/reperfusion

Chongming MU; Yupei CHEN; Daoru JI; Ling DAN; Wenting GONG; Lisha WANG

ABSTRACT

BACKGROUND:

KATP channel regulates the response of cells to hypoxia and ischemia, mediates and is involved in the protection for cells or tissue organs. Our previous research confirms that Shenfu injection has good protective effect on myocardial ischemia/reperfusion injury in rats. There have been no reports on whether this protective effect is related to KATP channel in WeiPu deriodical database, WanFang database and Medline database until October 2005.

OBJECTIVE:

To observe the protective effect of Shenfu injection on myocardial ischemia/reperfusion injury in rats, and analyze its correlation with KATP channel.

DESIGN:

Completely randomized grouping design, randomized controlled trial.

SETTING:

Department of Anesthesiology, Second Hospital Affiliated to Dalian Medical University; Department of Anesthesiology, Second Hospital Affiliated to Chongqing Medical University.MATERIALS Twenty-four adult SD rats of clean grade, of either gender, weighing 240 to 320 g, were employed in this trial. Shenfu injection (Sanjiu Medical & Pharmaceutical, Co., Ltd., Batch No. 031002) and glibenclamide (National Institute for the Control of Pharmaceutical and Biological Products) were employed.

METHODS:

This trial was carried out in the Laboratory of Anesthesiology, Second Hospital Affiliated to Chongqing Medical University from April to December 2004. Myocardial ischemia/reperfusion injury models were employed. Twenty-four rats were randomized into 4 groups, with 6 in each group sham-operation group [putting through thread, but without ligation of left anterior descending coronary artery, 8 mL/kg normal saline, intravenous injection (i.v.)], ischemia/reperfusion group (8 mL/kg normal saline, i.v.), Shenfu injection group (8 mL/kg Shenfu injection, i.v.) and Shenfu injection + glibenclamide group (0.33 mg/kg glibenclamide and 8 mL/kg Shenfu injection, i.v.). Administration in each group was conducted 15 minutes before ligation except for that in sham-operation group (immediately after putting through thread). About 6 mL blood was taken from cardiac apex. Left ventricular anterior wall was divided into 3 parts, and then which were used for homogenate, electron microscope observation and immunohistochemical detection separatety. The superoxide dismutase (SOD) activity, malondialdehyde (MDA) level, expressions of tumor necrosis factor-α(TNF-α) and interleukin 6 (IL-6)and plasm cTnl level in myocardial tissue were detected. Ultra-structural changes of myocardial tissue were observed.MAIN OUTCOME

MEASURES:

SOD activity, MDA level, expressions of TNF-α and IL-6, plasm cTnI level and ultra-structural changes of myocardial tissue.

RESULTS:

All the 24 rats were involved in the result analysis, without deletion. ① Compared with sham-operation group,SOD activity in myocardial tissue in ischemia/reperfusion group was decreased, while the expressions of TNF-α and IL-6 were increased, with statistical difference (P ＜ 0.01). MDA level in the ischemia/reperfusion group was higher than that in the sham-operation group (P ＜ 0.01); Compared with ischemia/reperfusion group, SOD activity was increased, MDA level and expressions of TNF-α and IL-6 were all decreased in Shenfu injection group(P ＜ 0.01); There were no significant differences in above-mentioned indexes between Shenfu injection group and Shenfu injection + glibenclamide group (P ＞0.05). ②Compared with sham-operation group, the plasm cTnl level in the ischemia/reperfusion group and Shenfu injection+ glibenclamide group was significantly increased (P ＜ 0.01); Compared with ischemia/reperfusion group, plasm cTnl level in the Shenfu injection group was significantly decreased in Shenfu injection group (P ＜ 0.01); There were no signifi cant differences in plasm cTnl level between Shenfu injection group and Shenfu injection + glibenclamide group. ③ In the sham-operation group, the ultrastructure of myocardial cells was basically normal and mitochondrium swelled a little; In the ischemia/reperfusion group, karyolysis appeared, mitochondrium swelled obviously and considerable neutrophils infil trated; In the Shenfu injection group, myofilament of myocardial cells dissolved, mitochondrium swelled and nuclear mem brane was integrity; In the Shenfu injection + glibenclamide group, mitochondrium obviously swelled, myofilament present ed focus dissolving, sarcoplasmic reticulum expanded a little and allochromacy assembled in the edge of cells.

CONCLUSION:

Glibenclamide suppresses myocardial KATP channel, but does not eliminate the protective effect of Shenfu injection on myocardial ischemia/reperfusion injury. KTAP channel does not play an important role in the protection of Shenfu injection for myocardial ischemia/reperfusion injury.