Relationship between lymphocyte apoptosis and endotoxin translocation after thermal injury in rats

AIM: To investigate the relationship between lymphocyte apoptosis in peripheral blood, spleen and mesenteric lymph nodes(MLN) and endotoxin translocation after thermal injury in rats. METHODS: In a Wistar rat model inflicted with 30% TBSA III degree scalding, serum LPS levels in portal vein and vena cava were quantified by tachypleus amebocyte lysate (TAL) technique. The analysis of peripheral blood lymphocyte was employed in in situ Cell Death Detection Kit and evaluated by flow cytometry. Apoptotic lymphocytes in paraffin-embedded spleen and MLN sections were examined by histologic analysis, in situ deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) and peroxidase (POD) staining. The images were taken by Cooldccd camera system, and the count and optical density value (transmission light) of apoptotic lymphocytes were analyzed with software Spot and Imagine proplus 4.10a(IPP4.10a). RESULTS: In the period of 3 to 48 postburn hours (PBHs) serum LPS level (x10(3) EU.L(-1)) in portal vein (2.11+/-0.02, 5.66+/-0.20, 3.70+/-0.22, 2.56+/-0.28, 0.90+/-0.11) was higher than that in vena cava (0.63+/-0.01, 1.53+/-0.18, 0.83+/-0.32, 0.52+/-0.12, 0.23+/-0.02, P【0.01), but both increased sharply in postburn rats (P【0.01) and reached a peak at 6 PBH. Analysis of apoptotic lymphocytes showed that the proportion (%) of postburn apoptotic cells was much higher than that in healthy rats (8.34+/-1.53, 8.13+/-1.81, 20.77+/-3.94, 23.90+/-3.92, 11.23+/-1.35 and 13.26+/-2.09 at 3, 6, 12, 24, 48 and 72 PBH, respectively, vs 3.99+/-1.72, P【0.01), especially after 6 PBH. The concentrations of lymphocytic apoptosis at 12 and 24 PBH were markedly higher than that at other time points. Meantime, few apoptotic lymphocytes were found in normal MLN, but increased postburn obviously (3+/-1 vs 546+/-83, 285+/-39, 149+/-30, 58+/-10, 36+/-11 and 33+/-9 in turn, P【0.01), especially at 3 PBH, whereas apoptotic lymphocytes were concentrated in splenic cortex before the burn and decreased obviously during 72 PBHs (499+/-186 vs 12+/-8, 19+/-15, 12+/-7, 100+/-15, 123+/-25 and 226+/-26 in turn, P【0.01) though a slight rise was found in the medulla after 24 PBH. Optical density of apoptotic lymphocytes was significantly reduced in spleen in the 24 PBHs and raised in MLN during 48 PBHs than that prior to the burn, respectively. CONCLUSION: Gut-origin LPS is a major cause of endotoxemia taken place early in rats following severe thermal injury and could induce extensive lymphocyte apoptosis in blood and MLN, which suggests an immunosuppression state could follow the initial injury and favores a septic state based on apoptotic mechanism.

湿球黑球温度指数在高温环境气象因素监测中的研究及应用

近年来,全球变暖导致高温天气频发,长期暴露在高温环境中的职业作业人员受气温、气湿、气流和热辐射等气象因素的综合影响很容易出现热伤亡。为加强高温作业人员的卫生保障,需对高温环境热强度进行实时监测以指导高温作业。湿球黑球温度(WBGT)指数考虑了温度、湿度、风速及热辐射等气象因素的影响,较单一热环境影响因素可以更科学地评估环境热强度,进而指导多群体高温作业。本文阐述了WBGT指数的起源发展及国内外有关WBGT指数的技术研究和应用现状,并提出了未来我国基于WBGT指数攻关技术的可能发展方向。

Effects of Acupuncture Pretreatment on Ischemic Cardiac Muscle Cell Apoptosis and Gene Expression in Ischemia-reperfusion Rats

Objective： To investigate the protective effects of acuptmcture pretreatment on ischemic myocardium, the protective mechanism of acupuncture pretreatment on ischemic myocardium was explored by observing the cardiac muscle cell apoptosis and the expression of HSP70 mRNA of ischemia-reperfusion injury rats treated with acupuncture pretreatment. Methods： Sixty-four Wistar rats were randomly divided into eight groups： control group, sham surgery group, ischemia-reperfusion group, ischemia pretreatment group, manual acupuncture pretreatment group （once a day）, electroacupuncture pretreatment group （once a day）, manual acupuncture pretreatment group （twice a day）, and electroacupuncture pretreatment group （twice a day）. The reperfusion model of rat myocardial ischemia was made. Expression of HSP70 mRNA was assayed by in situ hybridization, and cell apoptosis by TUNEL. Results： Compared with those in the control group and the sham surgery group, the apoptosis and the expression of HSP70 mRNA were increased in the ischemia-reperfusion group. Compared with those in the ischemia-reperfusion group, the cardiac muscle cell apoptosis was decreased and the HSP70 mRNA was increased in the rats treated with acupuncture pretreatment; meanwhile, acupuncture pretreatment twice a day had stronger effects than acupuncture pretreatment once a day and ischemia pretreatrnent. Conclusion： Acupuncture pretreatment can inhibit the cardiac muscle cell apoptosis, and up-regulate the expression of HSP70 mRNA in ischemia-reperfusion rats. Acupuncture pretreatment twice a day has stronger effects than pretreatment once a day.