目的 觀察黃芪多糖對嚴重燒傷大鼠心肌細胞凋亡的影響,并探討其作用機制。方法 120只大鼠隨機分為對照組、模型組、地塞米松(5 mg/kg)組和黃芪多糖10、20、40 mg/kg組,每組20只。采用92℃水浴18 s的方法制備大鼠30%總體表面積占比(TBSA)III度燒傷模型。各治療組均ip給藥1 mL/kg;對照組、模型組均ip給予生理鹽水1 mL/kg。24 h后,TUNEL法檢測心肌細胞凋亡情況并計算凋亡指數(shù),測定血清中心肌酶天冬氨酸氨基轉(zhuǎn)移酶(AST)、肌酸磷激酶(CPK)、乳酸脫氫酶(LDH)和肌鈣蛋白T(cTnT)水平,測定心肌組織中抗氧化酶超氧化物歧化酶(SOD)、過氧化氫酶(CAT)、髓過氧化物酶(MPO)活性和丙二醛(MDA)含量;RT-PCR法檢測心肌組織中AKT mRNA、bcl-2 mRNA、Bax mRNA表達并計算bcl-2/Bax表達比值;Western blotting法檢測心肌組織中caspase-3、NF-κB蛋白表達。結(jié)果 與模型組比較,黃芪多糖組大鼠心肌細胞凋亡數(shù)量明顯減少。與模型組比較,黃芪多糖20、40 mg/kg治療24 h能夠顯著降低嚴重燒傷大鼠心肌細胞凋亡指數(shù);AST、CPK、LDH、cTnT水平顯著降低;SOD、CAT、MPO活性顯著升高,MDA含量顯著降低;AKT mRNA、bcl-2 mRNA表達顯著上調(diào)、Bax mRNA表達顯著下調(diào),bcl-2/Bax比值顯著升高;顯著降低caspase-3、NF-κB蛋白表達量(P<0.05、0.01)。結(jié)論 黃芪多糖對嚴重燒傷大鼠心肌損傷具有保護作用,其作用機制可能與黃芪多糖能夠有效降低氧化應(yīng)激損傷和調(diào)節(jié)凋亡相關(guān)基因和蛋白表達有關(guān)。

Objective To investigate the protective effects of Astragalus polysaccharides on myocardial damage in severely burned rats, and discuss its mechanism. Methods Totally 120 rats were randomly divided into control group, model group, dexamethasone (5 mg/kg) group, and Astragalus polysaccharides (10, 20, and 40 mg/kg) groups, and each group had 20 rats. The model rats with 30% TBSA (III degree) were made by bathing in 92℃ water for 18 s. The rats in treatment groups were ip injected with the 1 mL/kg drugs, but rats in control and model groups were ip administered with 1 mL/kg normal saline. After 24 h, the apoptosis of cardiomyocytes was observed by TUNEL staining, and the apoptosis index was calculated. The contents of AST, CPK, LDH, and cTnT in serum were determined. The activities of SOD, CAT, and MPO, and the content of MDA in myocardial tissue were measured. The expression of AKT mRNA, Bax mRNA, and bcl-2 mRNA was determined by RT-PCR method, and the ratio of bcl-2/Bax was calculated. The expression of caspase-3 and NF-κB was determined by Western blotting. Results Compared with model group, the cardiomyocytes apoptosis in Astragalus polysaccharides groups were significantly improved. Compared with model group, the apoptosis index of Astragalus polysaccharides (20 and 40 mg/kg) groups were significantly decreased; The levels of AST, CPK, LDH, and cTnT in serum were significantly decreased; The activities of SOD, CAT, and MPO were significantly increased, but the content of MDA was significantly decreased; The expression of AKT mRNA and Bax mRNA were significantly up-regulated and the Bax mRNA was significantly down-regulated, the ratio of bcl-2/Bax was significantly increased. The expression of caspase-3 and NF-κB were significantly decreased (P < 0.05, 0.01). Conclusion Astragalus polysaccharides has protection on myocardial damage in severely burned rats, which might be related to reduce oxidative stress injury and regulate the expression of apoptosis-related genes and protein.

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