大鼠烫伤后不同时间切痂骨骼肌解偶联蛋白2、3 mRNA表达水平的改变

目的观察烫伤大鼠伤后不同时间切痂其骨骼肌解偶联蛋白(UCP)2、UCP3 mRNA表达水平的异同. 方法选用120只雄性Wistar大鼠,其中8只作为正常对照组;余下112只造成30%TBSAⅢ度烫伤后分成4组A组不切痂,分别于伤后8、24、96、120、168 h处死;B组伤后8 h切痂,于伤后24、96、120、168 h处死;C组伤后24 h切痂,伤后96、120、168 h处死;D组伤后96 h切痂,伤后120、168 h处死.测定各组大鼠各时相点的血清瘦素、肿瘤坏死因子(TNF)α含量以及腓肠肌UCP2、UCP3 mRNA表达水平. 结果 (1)血清瘦素水平A组大鼠伤后24～168 h均低于正常对照组(P<0.01),B、C、D组伤后120 h和(或)168 h均高于A组(P<0.01).(2)血清TNF-α水平A组伤后各时相点均高于正常对照组(P<0.01),B组伤后各时相点均低于A组(P<0.05或0.01).C组伤后168 h低于A组(P<0.05).(3)腓肠肌UCP2 mRNA的表达量A组大鼠在烫伤后8 h即已明显升高(P<0.01),24 h到达高峰,以后逐渐下降.B、C组伤后168 h时分别为0.32±0.20、0.35±0.15,明显低于同时相点A组 0.71±0.12(P<0.05).各组腓肠肌UCP3 mRNA表达的变化趋势与UCP2类似. 结论大鼠严重烫伤后UCP2、UCP3 mRNA表达上调可能是代谢率升高的重要因素之一,休克期切痂可降低这一表达,降低代谢率.

Changes in uncoupling protein-2, 3 mRNA expression in the scalded rats after escharectomy at different post scalding stages

OBJECTIVE: To investigate the expression of uncoupling protein (UCP)-2, 3 mRNA in skeletal muscle of the scalded rats after escharectomy at different post scalding stages. METHODS: One hundred and twenty Wistar rats were employed in the study, in which 8 served as normal control (C) and 112 were subjected to 30% TBSA 3rd degree scalding and then again, divided into 4 groups. The rats in A group were sacrificed on 8th, 24th, 96th, 120th and 168th post scalding hours (PSHs) without escharectomy. The rats in B group underment escharectomy at 8 PSH, and those in C group underment escharectomy at 24 PSH. All the rats in both groups were sacrificed on 96, 120 and 168 PSHs after escharectomy, Escharectomy was performed at 96 PSH in rats of D group, and they were sacrificed on 120 and 168 PSHs after escharectomy. The serum levels of leptin and TNFalpha, and the expression level of UCP2 mRNA were determined at all time points in all groups of rats. RESULTS: (1) The serum levels of leptin in A group were obviously lower than that in C group (P < 0.01) during 24 approximately 168 PSHs, while those in B, C and D groups were much higher than those in A group (P < 0.01) during 24 approximately 168 PSH. (2) The serum TNFalpha levels in A group at all time points were higher than that in control group, while that in B group at all time points were lower than that in A group (P < 0.05 or 0.01), and that in C group at 168 PSH was lower than that in A group (P < 0.05). (3) The UCP2 mRNA expression in skeletal muscle in A group was increased evidently since 8 PSH (P < 0.01), peaking at 24 PSH and lowering thereafter, while that in B and C groups at 168PSH was significantly lower than that in A group at the same time points (0.32 and 0.35 vs 0.71, P < 0.05). The trend of the change in UCP3 mRNA expression in skeletal muscle was similar to that of UCP2. CONCLUSION: The postburn up-regulation of UCP mRNA expression might play important roles in the increase of metabolic rate. Escharectomy during shock stage could lower down the expression of UCP2 and UCP3 mRNA expression, and it could be beneficial by lowering metabolic rate.