[Change in Toll-like receptor 4 expression on interstitial macrophages in acute lung injury].

Objective: To observe changes in the level of Toll-like receptor 4 (TLR4) mRNA and the expression of TLR4 protein in interstitial macrophages in serious thoracic injury.

Methods: A rat model of severe thoracic trauma was reproduced,then interstitial macrophages were isolated and collected by enzymatic digestion before and after trauma cultured. TLR4 mRNA and the expression of TLR4 protein were measured by Northern and Western blotting before trauma and 2, 4, 8, 16, 24 hours after trauma.

Results: A stable and reliable severe thoracic trauma model was successfully reproduced with 400 kPa impact on the up-right chest of rat by a multiple-function collision apparatus. The expression was up-regulated by trauma and the highest expression of interstitial macrophages occurred 8, 16 hours after the trauma, and returned to normal range at 24 hours.

Conclusion: The up-regulation of TLR4 might participate in the pathological process of excessive inflammation after trauma to the lung.