吗啡预处理对心力衰竭大鼠p38MAPK信号转导通路的影响

Impact of morphine preconditioning on p38MAPK signaling pathway in rats with heart failure

目的 探讨吗啡预处理对心力衰竭大鼠p38MAPK信号转导通路的影响。方法 选取30只体重200~220 g的SD健康SPF级实验大鼠,适应环境1周后,用盐酸阿霉素(ADR)腹腔注射造模心力衰竭(除对照组给生理盐水外,其余按1.5 ml/kg注射,1次/周,共6周,8 d后左心室短轴缩短率(LVFS)<30%表示模型建立成功)。40只大鼠中,20只造模,10只为正常对照,第8周将造模成功的20只大鼠随机分为模型组和吗啡预处理组,每组各10只,正常对照组和模型组不干预,吗啡预处理组灌注吗啡0.050 mg/kg,输注5 min,停5 min,重复3次。实验完成后,处死大鼠并进行腹腔静脉采血,随后通过离心分离上清液,用ELISA方法测定血浆中的BNP、ET-1和IL-6含量;同时,使用生理记录仪测量左心室的收缩末压(LVSP)、舒张末压(LVEDP),以及其内压的最大上升(+dp/dtmax)和下降(-dp/dtmax)速度;取大鼠心肌组织进行Western blot检测p38MAPK、p-p38MAPK蛋白表达;用RT-PCR检测p38MAPK mRNA的表达。结果 模型组和吗啡预处理组的左心室收缩压(LVSP)明显低于对照组,而左心室舒张末期压力(LVEDP)则高于对照组。左心室内压的最大上升速率(+dp/dtmax)在这两个组中均低于对照组,最大下降速率(-dp/dtmax)则高于对照组。吗啡预处理组的这些指标介于模型组和对照组之间,所有差异均具有统计学意义(P<0.05)。与对照组比较,模型组、吗啡预处理组血清BNP、ET-1和IL-6含量均升高,与模型组比较,吗啡预处理组上述指标降低(P<0.05)。与对照组相比,模型组与吗啡预处理组大鼠心肌组织中p38MAPK、p-p38MAPK的表达显著升高,吗啡预处理组表达介于两组之间,差异有统计学意义(P<0.05)。mRNA表达实验表明,模型组与吗啡处理组的心肌p38MAPK mRNA表达高于正常对照组,模型组高于其他两组,差异有统计学意义(P<0.05)。结论 本研究成功构建了心力衰竭大鼠模型。结果显示,吗啡预处理对部分心功能指标有显著改善,同时能降低血清中相关因子的浓度,并调节心肌组织中的关键蛋白和mRNA表达。这些发现表明,吗啡可能通过影响p38MAPK信号传导通路来发挥保护作用。

Objective To explore the impact of morphine preconditioning on the p38MAPK signaling pathway in rats with heart failure.Methods Thirty healthy SPF-grade SD rats weighing 200~220 g were acclimated for one week.Heart failure was modeled in 20 rats by intraperitoneal injection of doxorubicin hydrochloride(ADR)at a dose of 1.5 ml/kg once per week for six weeks,with successful modeling confirmed by a left ventricular fractional shortening(LVFS)of less than 30%eight days after the final injection.The remaining 10 rats served as the normal control group,receiving saline injections.The 20 rats with confirmed heart failure were randomly divided into two groups:the model group and the morphine preconditioning group,each with 10 rats.The normal control and model groups received no intervention,while the morphine preconditioning group was administered morphine at 0.050 mg/kg,infused for 5 minutes,paused for 5 minutes,and repeated three times.After the experiment,rats were sacrificed,and blood was collected via the abdominal vein.Plasma levels of BNP,ET-1,and IL-6 were measured using ELISA.A physiological recorder measured left ventricular systolic pressure(LVSP),end-diastolic pressure(LVEDP),and the maximum rates of pressure increase(+dp/dtmax)and decrease(-dp/dtmax).Myocardial tissue was collected for Western blot analysis of p38MAPK and p-p38MAPK protein expression and RT-PCR for p38MAPK mRNA expression.Results The model and morphine preconditioning groups showed significantly lower LVSP and higher LVEDP compared to the control group.Both groups also exhibited a decrease in+dp/dtmax and an increase in-dp/dtmax compared to the control group.The morphine preconditioning group's metrics were intermediate between the model and control groups,with all differences being statistically significant(P<0.05).Serum BNP,ET-1,and IL-6 levels were elevated in the model and morphine preconditioning groups compared to the control group,but lower in the morphine preconditioning group than in the model group(P<0.05).Myocardial expression of p38MAPK and p-p38MAPK was significantly higher in both the model and morphine preconditioning groups compared to the control group,with the morphine preconditioning group showing intermediate levels(P<0.05).mRNA expression analysis revealed higher p38MAPK mRNA in both the model and morphine preconditioning groups compared to the control group,with the highest levels in the model group(P<0.05).Conclusions This study successfully established a rat model of heart failure.Morphine preconditioning significantly improved certain cardiac function parameters,reduced serum factor levels,and regulated the expression of key proteins and mRNA in myocardial tissue.These findings suggest that morphine may protect through the modulation of the p38MAPK signaling pathway.