胰岛素强化治疗对烫伤大鼠心肌细胞作用的初步研究

目的 探讨胰岛素强化治疗对严重烫伤大鼠心肌的保护作用.方法 将18只SD大鼠随机分为3组,每组6只.行右颈静脉插管以备液体复苏及药物输入.假伤组大鼠在37 C水中假烫伤后给予生理量液体复苏;烫伤组造成总体表面积(TBSA)30%Ⅱ度烫伤后,常规予以生理盐水复苏;强化组于烫伤后给予胰岛素强化治疗,液体总量同烫伤组.于烫伤前后不同时间点经尾静脉采血测定血糖.伤后6 h处死动物,心脏取血测定心肌酶谱;取左心室组织,观察组织病理学变化;用蛋白质免疫印迹法检测活化的Akt(p-Akt)表达.结果 与假伤组比较,烫伤组伤后血糖及心肌酶谱水平均明显升高,伤后各时间点之间比较差异均有统计学意义(P<0.05或P<0.01).强化组经胰岛素强化治疗后,伤后各时间点血糖水平均显著低于烫伤组(4.5～5.2 mmol/L比7.6～8.4 mmol/L,P<0.05或P<0.01);心肌酶水平也显著降低乳酸脱氢酶(LDH):(2 369.3±178.9)U/L比(2 684.1±335.0)U/L,P<0.05;α-羟丁酸脱氢酶(α-HBD):(576.7±219.2)U/L比(1 002.0±347.1)U/L,P<0.01;心肌激酶(CK):(1 041.9±623.2)U/L比(2 447.1±1 183.7)U/L,P<0.01].镜下组织病理学观察均显示.强化组心肌细胞损伤和结构的改变明显减轻,并能显著上调P-Akt表达(1.18±0.43比0.24±0.11,P<0.01).结论 胰岛素强化治疗对严重烫伤大鼠心肌具有 明显的保护作用,此作用可能与增强Akt活化、抑制心肌细胞损伤有关.

Effect of intensive insulin treatment on cardiac myocytes of severely scalded rats

Objective To study the protective effect of intensive insulin treatment on cardiac myoeytes of severely scalded rats. Methods Eighteen model Sprague-Dawley (SD) rats were subjected to 30% total body surface area (TBSA) full thickness injury, and they were divided into three groups with 6 rats in each group. The right jugular vein was cannulated for fluid resuscitation and administration of drugs. The rats in burn group were injected with normal saline, the intensive insulin group with injection of insulin to maintain plasma glucose content in normal range, and the sham burn group received physiologic dose of saline without burn injury. Plasma glucose was monitored after burn injury. Rats were sacrificed at 6 hours postburn to examine plasma myocardial enzymes spectrum as well as histological and uhrastructure changes in cardiac tissue. The expression of p-Akt was detected by western blotting. Results Plasms glucose level was significally elevated in burn group within postburn 6 hours as compared with the sham burn group, and lowered in intensive insulin group (4.5～5. 2 mmol/L vs. 7. 6～8. 4 mmol/L, P±0. 05 or P<0.01). And the intensive insulin therapy could effectively inhibit the release of cardiac enzymes lactate dehydrogenase (LDH). (2 369.3±178. 9) U/L vs. (2 684.15±335. 0) U/L, P<0. 05; α-hydroxybutyrate dehydrogenase (α-HBD): (576.7±219.2) U/L vs. (1 002.0± 347. 1) U/L, P<0. 01; creatine kinase (CK): (1 041.95±623.2) U/L vs. (2 447.1 5±1 183.7) U/L, P<0.01]. The expression of p-Akt was significantly strengthened in the intensive insulin group (1. 185±0. 43 vs. 0. 245±0. 11, P<0. 01). Light microscopic and electron microscopic examinations showed that intensive insulin therapy could alleviate the injury to myocardial cells and structural changes. Conclusion Intensive insulin treatment possesses protective effect on cadiocytes after a severe burn, and it is related to its up-regulation of phosphorylation level of Akt in cadiocyte, thus inhibiting the damage to myocytes.