CECAL LIGATION AND DOUBLE PUNCTURE IMPAIRS HEAT SHOCK PROTEIN 70 HSP70 EXPRESSION IN THE LUNGS OF RATS

Induction of the heat shock response may improve outcome from pathophysiological disturbances. This improvement is associated with and believed to result from expression of heat shock protein HSP70. Therefore, we examined the temporal expression of HSP70 in an animal model of acute respiratory distress syndrome ARDS secondary to fecal peritonitis. Specifically, we hypothesize that sepsis in rats impairs pulmonary HSP70 expression. ARDS was induced in adolescent rats via cecal ligation and double puncture 2CLP. Shamoperated animals served as controls. Lung tissue was collected 0, 3, 6, 16, 24, and 48 h after 2CLP and sham operation. Northern blot hybridization analysis was performed to detect steadystate HSP70 messenger ribonucleic mRNA levels. HSP70 protein levels were determined via immunoblotting and immunohistochemistry. Mortality after 2CLP was 50 at 24 h and 75 at 48 h. Northern blot hybridization analysis revealed no significant change in steadystate HSP70 mRNA levels in lung at any time after 2CLP. HSP70 steadystate mRNA levels increased after sham operation and was higher than values in 2CLP at 6, 16, and 24 h. HSP70 protein levels did not change over time in either group. Thus, the expression of HSP70 does not change after 2CLP. Although lack of an increase in protein levels may be adaptive after sham operation, it is not appropriate after 2CLP. Therefore, failed HSP70 expression represents a form of pulmonary epithelial dysfunction that may contribute to lung injury in sepsis.