In this study, the rat models of severe hypothermia induced by seawater immersion were established in artificial seawater immersion at 15°C for 5 hours. With the rewarming measurement of 37°C water bath, the rewarming effects were evaluated by monitoring basic vital signs and dynamically detecting intestinal inflammation cytokines. Fifty Sprague-Dawley rats were randomly divided into five groups including the control group (group C), hypothermia group (group H), 2-hour rewarming group (group R2), 6-hour rewarming group (group R6), and 12-hour rewarming group (group R12), with 10 in each group. The basic vital signs of rats (i.e., core temperature, respiration, heart rate, and muscle tremor) were constantly recorded. The inflammatory factors were detected in the intestinal tissue via a protein chip GSR-CAA-67 of Innopsys, and the verification by reverse transcription-quantitative polymerase chain reaction. The levels of cytokines (interleukin IL-1β, IL-6, and IL-10) were detected from blood samples collected at the end of the observation period via enzyme-linked immunosorbent assay. The expression landscape of IL-1β in the intestinal tissue was validated by immunohistochemistry. Five hours of immersion in artificial seawater at 15°C successfully induced severe hypothermia of rats. After 2 hours of constant water bath rewarming at 37°C, the basic vital signs recovered to the normal level and maintained stably as well as the acute inflammatory reaction alleviated effectively, which indicated that 37°C of water immersion rewarming had the potential to be a suitable method for early treatment of water immersion hypothermia. After the process of hypothermia, several inflammatory cytokines of rats in rewarming groups changed distinctly with IL-1β, showing the most significant variations compared with group C, which confirmed IL-1β as a potential monitoring biomarker referring to the therapeutic effect of rewarming for severe hypothermia caused by seawater immersion.

Background Hypothermia secondary to accidental exposure is becoming increasingly prevalent in the general population; however, the mechanisms and early treatments of hypothermia require additional study. Methods A hypothermia-rewarming SD rat model was established by immersing rats in 15˚C seawater for 5h and then rewarming at 37˚C for 2, 6 and 12 h. The rats were randomly divided into a normal control group (group C), hypothermia group (group H) and rewarming group (group R). The changes in the levels of inflammatory factors and pathophysiology of the intestinal tissues of rats were assessed. The blood was collected in test tubes, and the levels of cytokines in the separated plasma were detected using ELISA. The intestinal tissue was ground and lysed, and protein expression profiles of 67 inflammatory factors were measured using a protein chip. These samples were further subjected to reverse transcription-quantitative (RT-q)PCR analysis and tissue section staining. Results The temperature of the abdomen and the physiological state of the rats was significantly altered during immersion in the hypothermic seawater, and returned to normal after rewarming. The protein chip showed that inflammatory factors, including IL-1β, IL-10 and IL-6, were differentially expressed in the intestine. Using ELISA, it was shown that IL-1β, IL-6 and IL-10 levels were also upregulated in the plasma. Comparing the ratios of IL-1β to IL-6 and IL-1β to IL-10, IL-1β was found to be significantly more upregulated compared with IL-10 and IL-6 in the intestine during hypothermia. The immunohistochemical staining of IL-1β showed that IL-1βexpression first increased then decreased during the rewarming period, and similar results were obtained based on RT-qPCR analysis. Conclusion Rewarming at 37˚C may be a suitable method for early treatment of hypothermia, and IL-1β may serve as a potential biomarker for assessing the severity of hypothermia.

目的 观察参附注射液对烧伤合并海水浸泡大鼠血清和肺组织的炎症因子及氧化应激指标的影响,初步探讨其作用机制.方法 将56只SD大鼠随机分为正常对照组(NC=6只)、烧伤合并海水浸泡组(SC=10只)、生理盐水对照组6 h(YW6=10只)、参附注射液组6 h(SF6=10只)、生理盐水对照组12 h(YW12=10只)、参附注射液组12 h(SF12=10只).NC组为正常对照组,不做任何处理;SC组是烧伤合并海水浸泡组,烧伤后浸泡3小时后即刻采样;SF和YW组是实验组,大鼠分别在实验前3天每天连续腹腔注射参附注射液或者生理盐水,剂量为15ml/kg.各实验组大鼠烧伤后再次注射15ml/kg的参附注射液或者生理盐水,然后在海水中浸泡6小时和12小时后取材,记录为SF6/12和YW6/12.分别检测各组大鼠血清和肺组织的炎性因子和氧化应激指标:白细胞介素-1β(IL-1β)、白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)、超氧化物歧化酶(SOD)、丙二醛(MDA)的含量;并且观察各组大鼠肺脏的病理改变.结果 烧伤合并海水浸泡组大鼠血清和肺组织炎性因子IL-1、IL-6、TNF-α水平及氧化应激指标MDA较正常组明显升高(P<0.05),T-SOD水平明显降低(P<0.05),参附注射液6小时组和12小时组炎症和氧化应激指标明显低于同时间的生理盐水注射组.相较对照组,参附注射液改善肺组织充血、水肿及炎性细胞浸润.结论 烧伤合并海水浸泡大鼠用参附注射液处理后能够降低血清和肺脏组织的IL-6、IL-1β、TNF-α等炎症因子及MDA氧化应激指标的水平,促进T-SOD的表达,从而减轻肺组织炎症,改善其损伤.