Induced hypothemia as new therapy for extensive severe burn injuries: Effects of hypothermia on the blood cytokine level inburned rats

诱导低温已被证明在严重损伤包括烧伤中具有保护作用。然而，这种冷疗法在临床病例中的应用仍然存在争议，并且以前没有详细研究过低温对细胞因子激活的影响。方法：将24只机械控制通气麻醉大鼠随机分为4组：1组（n=6），不给予任何药物，不造成热损伤;第2组（n=6），制备后行假热损伤。第3组（n=6），烫伤后维持常温。第4组（n=6），伤后给予亚低温（30℃）治疗。在第3组和第4组中，将大鼠置于30%总体表面积的III度烧伤中。在假烧伤或烧伤后2小时收集血液，用于测定细胞因子水平。采用酶联免疫吸附法测定肿瘤坏死因子-α（TNF-α）、白细胞介素-1 β（IL-1β）、白细胞介素-6（IL-6）、白细胞介素-8（IL-8）和白细胞介素-10（IL-10）的活性。热损伤（3、4组）诱导IL-β、IL-8、IL-10、IL-1β和IL-8显著升高，但4组低于3组。本研究证实，热损伤诱导IL-β、IL-8、IL-10升高，但低温组升高幅度明显较小。这些结果表明，诱导低温在烧伤早期具有保护作用，低温在热损伤的治疗中具有重要的临床意义。

The induced hypothermia has been shown to be protective in the severe injuries including the burn. However, this cold therapy remained controversial in the application on the clinical cases and the changes in cytokine activation in response to hypothermia have not been studied in detail previously. The aim of this study is to evaluate the effects or hypothermia on the activation of cytokines during the early phase or thermal injury.METHODS: Twenty four anesthetized rats under mechanically controlled ventilation were divided into four groups: In the group l, no preparations and no thermal injury were given (n=6, control). In the group 2 (n=6), the sham thermal injury was given after the preparations. In the group 3 (n=6), rats were maintained at normothermia after the thermal injury. In the group 4 (n=6), mild hypothermia (30℃) was applied after the thermal injury. In the groups 3 and 4, rats were submitted to a III-degree scald burn of 30% total body surface area. Bloods were collected at 2 hours after either the sham or scald burn for the determination of the cytokine level. The tumor necrosis factor-α (TNF-α), Interleukin-1β (IL-1β), Interleukin-6 (IL-6), Interleukin-8 (IL-8), and Interleukin-10 (IL-10) activities were assessed by the enzyme-linked immunosorbent assay.RESULTS: Thermal injuries (Groups 3 and 4) induced marked elevations of IL-β, IL-8, IL-10, IL-1β and IL-8 but they were less in Group 4 than in Group 3.CONCLUSION: This study confirmed that thermal injury induces increases in IL-β, IL-8, IL-10, but their increases were significantly smaller in the hypothermic group. These findings suggest that the induced hypothermia was protective in early burn phase and that the hypothermia is or great clinical benefit in the treatment or thermal injury.