高密度脂蛋白对严重烫伤大鼠肺功能的保护作用

目的了解高密度脂蛋白（HDL）对严重烫伤大鼠肺功能的作用及其机制。方法将Wistar大鼠分为对照组（15只）、烫伤组（60只）和HDL组（60只）。对照组大鼠不作处理；其余2组均造成30％TBSAIII度烫伤，伤后常规补液，其中HDL组伤后立即经尾静脉注入HDL（80mg／kg）。检测2组烫伤大鼠伤后12、24、48、72h血清胞间黏附分子1（ICAM—1）及肿瘤坏死因子α（TNF—α）的含量，并检测其动脉血二氧化碳分压（PCO2）氧分压（PO2）；观察大鼠伤后各时相点肺组织病理学变化。另检测对照组上述指标。结果与对照组比较，烫伤组大鼠伤后各时相点ICAM—1、TNF—α的含量及PCO，均显著升高（P〈0．05或P〈0．01），PO，显著降低（P〈0．05）。HDL组上述指标与对照组比较，差异无统计学意义（P〉0．05）；但与烫伤组比较，各时相点ICAM—1、TNF—α含量均显著降低（P〈0，05或P〈0．01）。伤后48h，烫伤组ICAM-1、TNF—α分别为（3．42±0．25）μg／L、（4．04±0．28）ng／L，明显高于HDL组（2．24±0．14）μg／L、（3．35±0．22）ng／L，P〈0．05或P〈0．01]。烫伤组大鼠伤后48h肺小血管周围炎性细胞浸润，肺内血管扩张出血，部分小血管管腔内红细胞淤滞凝集，形成“假血栓”；肺毛细血管内皮细胞连接松弛，内皮细胞水肿。HDL组肺内小血管周围炎性细胞浸润明显减轻；肺毛细血管内皮细胞连接较紧密。结论HDL对严重烫伤大鼠肺功能具有保护作用，可能与其抑制ICAM—1、TNF—α表达有关。

The protective effect of high density lipoprotein on the lung function of rats with severe burns

OBJECTIVE: To explore the protective effect of high density lipoprotein on the lung function of rats with severe burns. METHODS: One hundred and thirty-five Wistar rats were employed in the study and were randomly divided into control (n = 15, without injury), burn (n = 60, with 30% TBSA full-thickness burn on the back) and experimental (n = 60, with the injection of HDL (80 mg/kg) via the caudal vein immediately after burns)] groups. The rats in the latter two groups were resuscitated with intraperitoneal isotonic saline (50 ml/kg) 30 minutes after burns. The serum content of ICAM-1 and TNF-alpha as well as the blood content of PCO2 and PO2 of the rats in burn and experimental groups were determined at 12, 24, 48 and 72 post-burn hours (PBH) and in control group. The pathological changes in the lung tissue of the rats in all groups were observed under light microscope and electronic microscope at 48 PBH. RESULTS: PCO2 and the contents of ICAM-1 and TNF-alpha in burn group were significantly higher, but the PO2 was lower than those in control group at each time-point (P < 0.05 or P < 0.01). There were no obvious differences in the above indices between the experimental and control groups (P > 0.05), but the ICAM-1 and TNF-alpha levels in experimental group were markedly decreased than those in burn group at each time-point (P < 0.05 or P < 0.01). The ICAM-1 and TNF-alpha contents in burn group at 48 PBH were (3.42 +/- 0.25) microg/L and (4. 04 +/- 0.28) ng/L, respectively, which were markedly higher than those in experimental group (2.24 +/- 0.14) microg/L, (3.35 +/- 0.22) ng/L, P < 0.05 or P < 0.01]. Dilation of cappillaries, congestion and inflammatory infiltration in the pulmonary capillaries, and lossening of conjunction between pulmonary capillary vascular endothelial cells and endothelial swelling were observed in burn group at 48 PBH. Compared with the burn group, the injury was markedly alleviated in the experiment group, and the pulmonary capillary endothelial cells showed tighter junction. CONCLUSION: HDL exhibits a protective effect on the lung function of rats with severe burns via reducing the expression of ICAM-1 and TNF-alpha.