胰岛素强化治疗对严重烫伤大鼠血清凋亡配体的作用

目的 了解大鼠严重烫伤后血清凋亡相关配体的变化及胰岛素强化治疗的作用.方法 将150只Wistar大鼠随机分为假伤组、烫伤组和治疗组.烫伤组和治疗组烫伤后立即腹腔注射等渗盐水40 mL/kg复苏;治疗组伤后24 h皮下注射胰岛素0.25 U/100 g,以后每12小时注射1次,共注射5 d.第1～5天的剂量分别为0.25、0.50、0.75、1.00、1.25 U/100 g,将大鼠血糖控制在3～6 mmol/L.假伤组浸入37℃温水假伤后不进行液体复苏.于伤后1、4、7、10、14 d抽取各组大鼠腹主动脉血,采用酶联免疫吸附测定法检测血清TNF-α、可溶性Fas配体(sFasL)、可溶性Fas受体(sFas);放射免疫法检测血清胰岛素水平.结果 烫伤组大鼠伤后1 d血清TNF-α水平[(30.9±8.7)ng/L]即达高峰,与假伤组[(12.7±2.8)ng/L]和治疗组[(16.8±4.7)ng/L]比较,差异有统计学意义(P<0.01),以后逐渐下降;治疗组大鼠伤后血清TNF-α水平虽然有所上升,但在伤后7 d内明显低于烫伤组(P<0.01).烫伤组、治疗组大鼠血清sFasL分别在伤后7～14 d和4～10 d高于假伤组(P<0.05),此后逐渐恢复至正常水平.伤后4～10 d治疗组sFas水平明显高于烫伤组及假伤组(P<0.05).伤后7、10 d烫伤组大鼠血清sFasL与sFas比值高于假伤组,而治疗组则在伤后7 d低于烫伤组(P<0.05),伤后14 d 2组均接近正常水平.烫伤组大鼠血清胰岛素水平在伤后4～10d低于假伤组(P<0.05).治疗组从伤后第1天起血清胰岛素水平即显著升高,伤后4 d[(327±15)μU/mL]达高峰,并显著高于假伤组[(42±15)μU/mL,P<0.01]和烫伤组[(28±10)μU/mL,P<0.01],随着治疗的进行,该指标逐渐恢复到正常水平.结论 胰岛素可能通过调节凋亡配体的分泌而抑制烧伤后细胞凋亡.

Effect of intensive insulin therapy on apoptosis-related ligands in serum in rats with severe scald

Objective To investigate changes in apoptosis-related ligands in serum in rats with se-vere scald and the effect of intensive insulin therapy on the changes. Methods One hundred and fifty Wistar rats were randomly divided into 3 groups: sham burn(SB), scald(S) and treatment(T) groups. Rats in S and T groups were inflicted with 40% TBSA full-thickness burn, followed by intraperitoneal injection with 40 mL/kg of isotonic saline for resuscitation. Rats in T group were subcutaneously injected insulin in a dose of 0.25 U/100 g24 hours after burn injury, and every 12 hours for 5 days (0.25, 0.50, 0.75, 1.00, 1.25 U/100 g each day, respectively) to control the level of blood glucose between 3 and 6 mmol/L. Rats in SB group were sham scalded at 37 ℃ without resuscitation. Blood was drawn from abdominal aorta on 1, 4, 7, 10, 14 post burn day(PBD) for determination of serum levels of TNF-α, soluble Fas ligand(sFasL) and soluble Fas receptor(sFas) by enzyme-linked immunosorbent assay (ELISA), and insulin by radioim-munity assay (RIA). Results The serum level of TNF-α in S group peaked on 1 PBD(30.9±8.7) ng/L, which showed statistically significant difference when compared with that of SB and T groups (12.7±2.8) ng/L, (16.8±4.7)ng/L, respectively, P < 0.01), then lowered gradually to become similar to that of SB group on 7 PBD. The level of TNF-α in T group increased gradually, but was obviously lower than that of S group on 1, 4, 7 PBD(P<0.01). The level of sFasL in S (on 7-14 PBD) and T(4-10 PBD) groups was significantly higher than that in SB group (P <0.05), then lowered to normal level. The levels of sFas on 4-10 PBD in T group were obviously higher than that in S and SB group(P < 0.05). Ratio of sFasL to sFas in serum of S group was higher than that in SB group on 7, 10 PBD, which was higher than that in T group on 7 PBD(P <0.05). There was significant decrease in serum level of insulin in S group compared with that of SB group on 4-10 PBD(P<0.05). The level of insulin in T group increased on 1 PBD, peaked on 4 PBD(327±15 μU/mL), which was significantly higher than that in SB and S groups(42±15, 28±10 μU/mL, respectively, P <0.01) , then decreased gradually to normal level. Conclusions Insulin may inhibit apoptosis after burn by down-regulating secretion of apoptotic ligands.