Objective: To investigate the influence and its significance of expression of Toll-like receptor mRNA in lung tissue of mice with hemorrhagic shock without resuscitation.
Methods: Forty-five C57BL/6 mice were randomly divided into hemorrhagic shock group, lipopolysaccharide (LPS) group (positive control, 5 mg/kg LPS was injected into caudal vein), and sham-operation group (negative control), with 15 mice in each group. The hemorrhagic shock model was reproduced by heart puncture. The total RNA from lung tissue of mice in each group was extracted by Tripure reagent and the expression of Toll-like receptor 2 (TLR2) and TLR4 mRNA were measured by semi-quantitative reverse transcription-polymerase chain reaction.
Results: Hemorrhagic shock and LPS challenge increased lung neutrophil infiltration and erythrocyte diapedesis. The expression of TLR2 mRNA and TLR4 mRNA could be found in normal lung tissues, but they were increased at 0, 1, 2, 4, and 6 hours after hemorrhagic shock and LPS challenge. There was no change in the sham-operation group.
Conclusion: The increased expression of TLR2 and TLR4 gene in lung tissue after hemorrhagic shock is closely correlated with the onset of acute lung injury. Though the innate immunity is enhanced, the animals are more susceptible to subsequent irritations. Over-expression of TLR2 and TLR4 may induce structural and functional damage to organs.