基于“温通心阳”功效的桂枝和肉桂配方颗粒对大鼠心肌缺血/再灌注损伤模型保护作用的实验研究

Experimental study of cardioprotective effects of Cinnamomi Ramulus and Cinnamomi Cortex formula granules on myocardial ischemia/reperfusion injury in rats based on efficacy of "warming and coordinating heart Yang"

基于“温通心阳”功效平行观察桂枝配方颗粒(Cinnamomi Ramulus formula granules)和肉桂配方颗粒(Cinnamomi Cortex formula granules)对大鼠急性心肌缺血/再灌注损伤(myocardial ischemia/reperfusion injury, MI/RI)的保护作用及潜在机制。90只SD雄性大鼠按体质量随机分为假手术组(sham),模型组,桂枝与肉桂配方颗粒各自低、高剂量(0.5、1.0 g·kg^(-1))组,每组15只。造模前,各组大鼠每天灌胃给药1次,连续给药7 d, sham组和I/R组给予等体积生理盐水。末次给药1 h后,除sham组外,其余各组大鼠均采用结扎冠状动脉左前降支制备缺血30 min、再灌注120 min的MI/RI大鼠模型,假手术组大鼠仅穿针不予结扎,其余处理相同。考察桂枝和肉桂配方颗粒对MI/RI大鼠心肌功能、心肌梗死面积、心肌病理学和心肌超微结构的改变、心肌细胞凋亡、心肌损伤标志物及炎症因子的影响。RT-PCR法检测大鼠心肌组织中核苷酸结合寡聚化结构域样受体家族pyrin结构域蛋白3(nucleotide-binding oligomerization domain-like receptor family pyrin domain protein 3, NLRP3)炎症小体、凋亡相关斑点样蛋白(apoptosis-associated speck-like protein containing a CARD, ASC)、切割型半胱氨酸天冬氨酸特异性蛋白酶-1(cysteinyl aspartate specific proteinase-1, caspase-1)、Gasdermin-D(GSDMD)、白细胞介素-1β(interleukin-1β, IL-1β)和白细胞介素-18(interleukin-18, IL-18)等基因表达水平。Western blot法检测大鼠心肌组织中NLRP3、caspase-1、GSDMD和N-GSDMD等蛋白表达水平。桂枝和肉桂配方颗粒预处理均能明显改善MI/RI大鼠的心肌功能,减小心肌梗死面积,抑制心肌细胞凋亡,降低血清中乳酸脱氢酶(lactic dehydrogenase, LDH)、肌酸激酶MB同工酶(creatine kinase MB isoenzyme, CK-MB)、天冬氨酸转氨酶(aspartate transaminase, AST)和心肌肌钙蛋白Ⅰ(cardiac troponinⅠ, cTnⅠ)的含量。此外,桂枝和肉桂配方颗粒预处理能明显降低MI/RI大鼠血清中IL-1β、白细胞介素-6(interleukin-6, IL-6)和肿瘤坏死因子-α(tumor necrosis factor-α, TNF-α)水平。RT-PCR结果表明,桂枝和肉桂配方颗粒预处理能下调模型大鼠心肌NLRP3、caspase-1、ASC和下游细胞焦亡相关效应物质如GSDMD、IL-18和IL-1β的mRNA表达水平。Western blot结果显示,桂枝和肉桂配方颗粒预处理还可下调模型大鼠心肌NLRP3、caspase-1、GSDMD和N-GSDMD的蛋白表达。综上所述,桂枝和肉桂配方颗粒均对大鼠MI/RI具有明显的心肌保护作用,其机制可能与抑制NLRP3/caspase-1/GSDMD信号通路从而减轻心肌炎症反应有关。

This study aimed to parallelly investigate the cardioprotective activity of Cinnamomi Ramulus formula granules(CRFG) and Cinnamomi Cortex formula granules(CCFG) against acute myocardial ischemia/reperfusion injury(MI/RI) and the underlying mechanism based on the efficacy of "warming and coordinating the heart Yang". Ninety male SD rats were randomly divided into a sham group, a model group, CRFG low and high-dose(0.5 and 1.0 g·kg^(-1)) groups, and CCFG low and high-dose(0.5 and 1.0 g·kg^(-1)) groups, with 15 rats in each group. The sham group and the model group were given equal volumes of normal saline by gavage. Before modeling, the drug was given by gavage once a day for 7 consecutive days. One hour after the last administration, the MI/RI rat model was established by ligating the left anterior descending artery(LAD) for 30 min ischemia followed by 2 h reperfusion except the sham group. The sham group underwent the same procedures without LAD ligation. Heart function, cardiac infarct size, cardiac patho-logy, cardiomyocyte apoptosis, cardiac injury enzymes, and inflammatory cytokines were determined to assess the protective effects of CRFG and CCFG against MI/RI. The gene expression levels of nucleotide-binding oligomerization domain-like receptor family pyrin domain protein 3(NLRP3) inflammasome, apoptosis-associated speck-like protein containing a CARD(ASC), cysteinyl aspartate specific proteinase-1(caspase-1), Gasdermin-D(GSDMD), interleukin-1β(IL-1β), and interleukin-18(IL-18) were determined by real-time quantitative polymerase chain reaction(RT-PCR). The protein expression levels of NLRP3, caspase-1, GSDMD, and N-GSDMD were determined by Western blot. The results showed that both CRFG and CCFG pretreatments significantly improved cardiac function, decreased the cardiac infarct size, inhibited cardiomyocyte apoptosis, and reduced the content of lactic dehydrogenase(LDH), creatine kinase MB isoenzyme(CK-MB), aspartate transaminase(AST), and cardiac troponin Ⅰ(cTnⅠ). In addition, CRFG and CCFG pretreatments significantly decreased the levels of IL-1β, IL-6, and tumor necrosis factor-α(TNF-α) in serum. RT-PCR results showed that CRFG and CCFG pretreatment down-regulated the mRNA expression levels of NLRP3, caspase-1, ASC, and downstream pyroptosis-related effector substances including GSDMD, IL-18, and IL-1β in cardiac tissues. Western blot revealed that CRFG and CCFG pretreatments significantly decreased the protein expression levels of NLRP3, caspase-1, GSDMD, and N-GSDMD in cardiac tissues. In conclusion, CRFG and CCFG pretreatments have obvious cardioprotective effects on MI/RI in rats, and the under-lying mechanism may be related to the inhibition of NLRP3/caspase-1/GSDMD signaling pathway to reduce the cardiac inflammatory response.