Decrease of heatstroke-induced multiorgan dysfunction by whole body cooling in streptozotocin-induced diabetic rats

The present study was conducted to assess the effects of whole body cooling on multiorgan dysfunction that occurred during heatstroke in streptozotocin (STZ)-induced diabetic rats. The rats were randomly divided into four groups: [1] the normal control, [2] diabetic control, [3] diabetic heatstroke, and [4] diabetic heatstroke-whole body cooling (WBC). They were exposed to ambient temperature of 43°C for exactly 58 min to induce heatstroke. When the diabetic heatstroke rats underwent heat stress, their survival time values were found to be 11-13 min. Immediately after the onset of heatstroke, resuscitation with body cooling greatly improved survival (221-257 min). Compared with the diabetic (STZ-treated) controls, the diabetic-heatstroke rats displayed higher levels of body temperature, intracranial pressure, serum nitric oxide metabolite, tumor necrosis factor-α and dihydroxybenzoic acid, blood urea nitrogen, creatinine, alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase. In contrast, the values of mean arterial pressure, cerebral perfusion pressure, and brain levels of local blood flow, and partial pressure of oxygen were all significantly lower during heatstroke. The cerebrovascular, renal, and hepatic dysfunction, the increased levels of nitric oxide metabolites, tumor necrosis factor-α, and dihydroxybenzoic acid in the serum during heatstroke were significantly reduced by WBC. Although the serum interleukin-10 maintained at a negligible levels before heat stress, they were significantly elevated by WBC in diabetic-heatstroke rats. The data demonstrate that heatstroke-induced multiorgan dysfunction in streptozotocininduced diabetic rats can be decreased by WBC.