[The expression of TLR4 in rat acute lung injury induced by lipopolysaccharide and the influence of Eucalyptus globulus oil].

OBJECTIVE

To observe the distribution of toll-like receptor 4 (TLR4) in rats' respiratory tract. To study the influence of LPS and Eucalyptus globulus oil on the distribution of TMR4.

METHOD: The Sprague-Dawley rats were intratracheally instilled with lipopolysaccharide (LPS,2 mg x kg(-1) per day) for two days to induce acute lung injury. The rats were sacrificed at 72 hours after LPS instillation. Lung morphology was studied. Leukocytes in Bronchoalveolar lavage fluid (BALF) were measured and TLR4 were detected by immunohistochemistry.

RESULT: The result of immunohistochemistry showed that TLR4 distributed widely in common rats' respiratory tract. In the group of acute lung injury, the number of leucocyte in BALF was increased apparently, the inflammation in bronchus and bronchioles was more apparently than that of the control group in morphology. And the expression of TLR4 was reinforced in main bronchus and bronchioles. In the group of E. globules oil (300 mg x kg(-1)), the leucocyte number was decreased apparently in BALF, the inflammation was lightened and the expression of TLR4 decreased as compared with the group of models.

CONCLUSION

The expression of TLR4 distributes widely in rats' respiratory tract. The stimulation of LPS can reinforce the expression of TLR4. The E. globules oil can reduce the increase of TLR4 induced by LPS in bronchioles.