早期应用冬眠合剂对严重烫伤大鼠小肠的保护作用

目的 了解早期应用冬眠合剂对严重烫伤大鼠小肠的保护作用.方法 将66只雄性SD大鼠按随机数字表法分为假伤组6只、烫伤组30只、烫伤+冬眠合剂组30只.麻醉后,将后2组大鼠造成30%TBSAⅢ度烫伤,假伤组37℃水浴模拟烫伤.3组大鼠伤后均立即腹腔注射乳酸钠林格液(2 mL·kg-1·%TBSA-1)复苏;同时烫伤+冬眠合剂组皮下注射冬眠合剂(50 mg/mL哌替啶、25 mg/mL氯丙嗪、25 mg/mL异丙嗪各1 mL加入125 mL生理盐水中)12 mL/kg,假伤组和烫伤组注射生理盐水12 mL/kg.分别于伤后3、6、12、24、48 h取烫伤组与烫伤+冬眠合剂组大鼠各6只(假伤组伤后3 h取材),采集血液和小肠组织标本.观察烫伤组与烫伤+冬眠合剂组大鼠伤后24 h、假伤组伤后3 h小肠组织病理变化,并用免疫组织化学法检测小肠组织胞间黏附分子1(ICAM-1)和CD68的表达.采用ELISA法测定各组大鼠血浆D-乳酸、二胺氧化酶(DAO)、IL-1β、TNF-α、IL-10水平.数据行单因素方差分析.结果 (1)伤后24 h,烫伤组大鼠小肠黏膜轻度出血,炎症细胞浸润、上皮细胞脱落;烫伤+冬眠合剂组较烫伤组肠绒毛排列规则,无明显充血、水肿表现.(2)烫伤组小肠ICAM-1和CD68阳性表达率分别为(1.69±0.27)%和(0.80±0.09)%,均显著高于假伤组的(0.77±0.10)%和(0.30±0.05)%(F值分别为77.303、66.933,P<0.05或P<0.01)与烫伤+冬眠合剂组的(0.53±0.09)%和(0.32±0.06)%(F值同前,P值均小于0.01).(3)烫伤+冬眠合剂组大鼠伤后12、24 h D-乳酸水平明显低于烫伤组(F值分别为20.936、19.854,P值均小于0.01).烫伤+冬眠合剂组DAO水平于伤后3、12 h显著低于烫伤组(F值分别为21.930、11.342,P值均小于0.05).(4)烫伤组各时相点IL-1β、TNF-α水平均明显高于假伤组(P值均小于0.01),烫伤+冬眠合剂组伤后6、12、24 h IL-1β、TNF-α水平均低于烫伤组(F值分别为96.517、17.365、79.715与21.328、17.682、28.424,P<0.05或P<0.01);烫伤+冬眠合剂组各时相点IL-10水平均高于烫伤组,并在6、24 h时差异具有统计学意义(F值分别为8.668、19.634,P<0.05或P<0.01).结论 早期应用冬眠合剂可减轻严重烫伤大鼠小肠黏膜水肿和损害,该机制可能与其降低肠道ICAM-1的表达和血液炎症介质水平、减少肠道局部炎症细胞数量有关.

Protective effect of early application of lytic cocktail on small intestine of severely scalded rats

Objective To study the protective effect of early application of lytic cocktail on small intestine of severely scalded rats. Methods Sixty-six male SD rats were divided into sham injury group (SI, n =6) , scald group (S, n = 30) and scald + lytic cocktail group (SL, n =30) according to the random number table. After anesthesia, rats in the latter 2 groups were inflicted with 30% full-thickness scald, while rats in S group were sham scalded with 37 ℃ water. Resuscitation was carried out by intraperitoneal injection with 2 mL · kg-1 · %TBSA-1 lactated Ringer's solution in all rats; meanwhile 12 mL/kg lytic cocktail [ 1 mL pethidine (50 mg/mL) + 1 mL chlorpromazine (25 mg/mL) + 1 mL promethazine (25 mg/mL) + 125 mL saline] was hypodermically injected to rats in SL group, while 12 mL/kg saline was injected into rats in the other 2 groups. Samples of blood and small intestine were harvested from S and SL groups at post scald hour (PSH) 3, 6, 12, 24, 48 and from SI group at PSH 3, with 6 rats in each group at each time point. Pathological changes in intestine were observed, and the expression of intercellular adhesion molecule 1 (ICAM-1) and CD68 were determined with immunohistochemistry at PSH 24 for S and SL groups and at PSH 3 for SI group. Plasma levels of D-lactate, diamine oxidase (DAO) , IL-1β, TNF-α, IL-10 were determined with ELISA. Data were processed with one-way analysis of variance. Results (1) At PSH 24, mild hemorrhage, inflammatory cell infiltration and epithelial cell shedding were observed in small intestinal mucosa of rats in S group.Compared with S group, the intestinal villi of SL group were arranged regularly without obvious hyperemia and edema. (2) Expression levels of ICAM-1 and CD68 [(1. 69 ± 0.27)%, (0.80 ±0.09)%] in S group were significantly higher than those in SI group [(0.77 ± 0. 10) % , (0. 30 ± 0. 05) % , with F value respectively 77. 303 and 66. 933 , P < 0.05 or P < 0.01] and SL group [(0. 53 ± 0.09) % , (0. 32 ± 0. 06) % , with F value respectively 77. 303 and 66. 933 , P values all below 0.01]. (3) D-lactate levels of rats in SL group were significantly lower than those of rats in S group at PSH 12, 24 (with F value respectively 20. 936 and 19. 854, P values all below 0.01), while DAO levels of rats in SL group were significantly lower than those of rats in S group at PSH 3, 12 (with F value respectively 21. 930 and 11. 342 , P values all below 0. 05).(4) The levels of IL-1β and TNF-α in S group were significantly higher than those of SI group at each time point (P values all below 0.01). The levels of IL-1β and TNF-α in SL group were significantly higher than those of S group at PSH 6, 12 and 24 (with F value respectively 96. 517 , 17.365, 79.715 and 21. 328, 17. 682, 28.424, P <0.05 or P <0.01). IL-10 level in SL group was higher than that in S group at each time point, and the differences were statistically significant at PSH 6 and 24 (with F value respectively 8. 668, 19. 634, P < 0.05 or P < 0.01). Conclusions Early administration of lytic cocktail can attenuate edema and injury of intestinal mucosa in severely scalded rats. The mechanism may lie in that it can reduce the expression of ICAM-1 in intestinal mucosa, decrease the number of intestinal inflammatory cells and regulate the levels of inflammatory cytokines.