严重烧伤早期心肌收缩性与钙转运功能变化

Myocardial contractile and calcium transport function after severe burn injury

目的研究烧伤早期心肌肌浆网(SR)钙转运功能变化,探讨其在烧伤后心肌收缩功能下降发病中的作用。方法采用30％TBSAⅢ度烧伤大鼠模型,离体心脏灌流,测定伤前及伤后心肌室内压最大变化速率(±dp/dtmax)变化,制备心肌肌浆网,应用微孔滤膜过滤技术测定心肌SR^(45)Ca^(2+)转运功能改变。结果与对照组相比,烧伤组左心室±dp/dtmax明显降低(P<0.01),心肌SRCa^(2+)-ATPase活性及SR^(45)Ca^(2+)摄取初速度、摄取容量均明显降低(P<0.01),偶联率比对照值大幅度下降。结论烧伤后早期心肌肌浆网Ca(2+)转运功能严重障碍,其是烧伤后心肌收缩功能降低的重要因素之一。

Objective This study examined the changes in myocardial calcium transport function and what roles it played in cardiac dysfunction after severe burn injury. Methods Contraction relaxation properties of the left ventricule (LV) were studied in isolated heart preparations of Wistar rat 3,8,24 hours after 30% TBSA full thickness burn. Sarcoplasmic reticulum (SR) calcium transport function was measured by millipore filtration technique. Results The maximal rates of LV pressure elevation (+dp/ dtmax) and depresssion (-dp/dtmax) in burn group were significantly lower than that in control group (P<0.01). The initial rate and capacity of calcium uptake by SR decreased markedly in burn group than in control group (P<0.01). In addition, calcium dependent ATPase activity and coupling ratio of SR were also markedly depressed. Conclusion SR calcium transport function depression was closely related to cardiac contractile dysfunction ,and the former is one of the important mechanism for cardiac contrac- tile dysfunction after severe burn injury.