烫伤延迟复苏大鼠组织白细胞介素18mRNA表达的变化

目的 探讨烫伤延迟复苏后不同组织白细胞介素18（IL－18）mRNA的动态表达规律。方法 采用大鼠TBSAⅢ度烫伤延迟复苏模型，54只大鼠随机分为正常对照组、烫伤延迟复苏组、选择性消化道脱污染（SDD）预防组，分别在伤前及伤后2、8、16、24h，采用逆转录聚合酶链式反应，检测肠、肺、肝、肾等组织IL－18 mRNA含量。结果 烫伤延迟复苏后体循环内毒素水平显升高，8、24h达高峰（P＜0．01），给予SDD预防治疗可显降低内毒素峰值（P＜0．05）；另一方面，烫伤后2h，肺、肝、肾等组织IL－18 mRNA含量表达较伤前值有显升高，烫伤后8h达高峰（P＜0．01），且一直持续至伤后24h，给予SDD预防后可不同程度抑制IL－18 mRNA的表达（P＜0．05－0．01）。相关分析显示，体循环内毒素水平同肠、肺、肝组织IL－18 mRNA呈显正相关（r值分别为0．298、0．290、0．365，P＜0．05－0．01）。结论 肠、肺、肝、肾等组织IL－18 mRNA表达在烫伤早期即显增多，并呈逐渐升高的趋势，创伤后内毒素血症对机体多种组织IL－18 mRNA基因表达具有重要影响。

The dynamic change in the expression of interleukin 18 mRNA in the tissue of scalded rats after delayed resuscitation

OBJECTIVE: To explore the dynamic change in the expression of interleukin 18 (IL-18) mRNA in the tissue of scalded rats after delayed resuscitation. METHODS: Wistar rats inflicted by 30% TBSA III degree scalding were employed as the model. Fifty-four rats were randomly divided into normal control (C), scalding and delayed resuscitation group (SD) and preventive group of selective decontamination of digestive tract (SDD) group. The RT-PCR was applied to determine the tissue contents of IL-18 mRNA in intestine, lungs, liver and kidneys at 2, 8, 16 and 24 PBHs. RESULTS: Plasma level of LPS increased significantly and reached summit level at 8 and 24 PBHs after delayed resuscitation after scalding (P < 0.01), but decreased obviously (P < 0.05) after the preventive application of SDD. Furthermore, the expression of tissue IL-18 mRNA in lungs, liver and kidneys since 2 PBHs increased evidently when compared to that before scalding and reached peak value at 8 PBH (P < 0.01) and lasted up to 24 PBHs. The expression of IL-18 mRNA could be inhibited to varying degrees by preventive application of SDD (P < 0.05-0.01). It was indicated by correlative analysis that plasma level of LPS was positively correlated to the expression of tissue IL-18 mRNA in intestine, lungs and liver (r = 0.298, 0.290 and 0.365 respectively with P < 0.05-0.01). CONCLUSION: The expression of tissue IL-18 mRNA in intestine, lungs, liver and kidneys increased significantly during early postburn stage and progressively enhanced thereafter. And the expression of tissue IL-18 mRNA in a variety of body tissue was significantly affected by post-traumatic endotoxemia.