Lim, Chin Leong and Wilson, Gary and Brown, Lindsay and Coombes, Jeff S. and Mackinnon, Laurel T. (2007) Pre-existing inflammatory state compromises heat tolerance in rats exposed to heat stress. American Journal of Physiology: Regulatory, Integrative and Comparative Physiology, 292 (1). R186-R194. ISSN 0363-6119
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Identification Number or DOI: doi: 10.1152/ajpregu.00921.2005
This study investigated the roles of endotoxemia and heat-induced tissue damage in the pathology of heat stroke. In groups of eight, male Wistar rats were treated with heat exposure only (HE), or heat exposure with turpentine (T+HE), dexamethasone (D+HE), and turpentine and dexamethasone combined (TD+HE). The rats remained sedated for 2h after receiving the respective treatments, followed by heat exposure until the core temperature (Tc) was 42°C for 15min; control rats received turpentine (T), dexamethasone (D), and turpentine and dexamethasone (TD) without heat stress. Blood samples were collected before treatment (baseline I), after 2 h of passive rest (baseline II), at Tc 40°C (T40), and 15 min after achieving Tc 42°C (T42). No rats died in the nonheat-stressed groups. Survival rate was lowest in the TD+HE rats (37.5%), followed by the HE (62.5%), T+HE (75%), and D+HE (100%) rats (P < 0.05). The duration of survival at T42°C was shortest in the TD+HE rats (9.9 ± 6.2 min) (P < 0.01), followed by the T+HE (11.3 ± 6.1 min) and the HE (12.2 ± 4 min) (P < 0.05) rats. The increase in plasma IL-6 concentrations was highest in the T+HE (352%) and HE (178%) rats (P < 0.05). D+HE treatment suppressed the increases in plasma aspartate transaminase, alanine aminotransferase, and IL-6 and LPS concentrations during severe heat stress. Heat stroke can be triggered by endotoxemia or heat-induced tissue damage, and preexisting inflammation compromises heat tolerance, whereas blocking endotoxemia increases heat tolerance.
|Item Type:||Article (Commonwealth Reporting Category C)|
|Additional Information:||First published 21 Sep 2006 Permanent restricted access to paper due to publisher copyright restrictions.|
|Uncontrolled Keywords:||dexamethasone; inflammation; turpentine|
|Fields of Research (FOR2008):||11 Medical and Health Sciences > 1116 Medical Physiology > 111601 Cell Physiology|
11 Medical and Health Sciences > 1102 Cardiovascular Medicine and Haematology > 110202 Haematology
10 Technology > 1004 Medical Biotechnology > 100499 Medical Biotechnology not elsewhere classified
|Socio-Economic Objective (SEO2008):||E Expanding Knowledge > 97 Expanding Knowledge > 970111 Expanding Knowledge in the Medical and Health Sciences|
|Deposited On:||09 Sep 2011 17:07|
|Last Modified:||22 Aug 2012 16:13|
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