Expression of TLR4 gene in mice exposed to 230 kPa hyperbaric oxygen during different time courses

Abstract

Objective To investigate the expression of TLR4 gene in mice exposed to 230 kPa hyperbaric oxygen during different time courses, and the role of TLR4 in the development of pulmonary oxygen toxicity. Methods Forty C57BL/6 mice were randomly divided into 4 groups: the control group(UPTD, unit pulmonary toxicity dose =0), the 2-h exposure to 230 kPa oxygen group (UPTD =347), the 6-h group (UPTD = 1044), the 10-h group (UPTD = 1740), the norm oxygen group (hyperbaric and normal O_2 density group). Pathologic changes in the pulmonary tissue were observed and weight ratio of wet lung to dry lung and the expression of TLR4 were measured in vivo by using applied quantitative real time PCR. Results Pulmonary collapse hemorrhage, congestion and leucocyte aggregation in lung interstitium were observed in mice exposed to pure oxygen. Conclusions Lesion of the pulmonary tissue in mice deteriorated gradually with the extension of exposure. Highly negative correlation between TLR4 and UPTD indicated that TLR4 might be involved in the development of pulmonary oxygen toxicity, whose mechanism remained to be explored. Key words: Pulmonary oxygen toxicity; Toll-like receptor 4; Acute lung injury