The Expression Of TLR4 In Rat Acute Lung Injury Induced By Lipopolysaccharide And The Influence Of Inhaling Nitric Oxide

【Objective】To observe the distribution of toll-like receptor 4 (TLR4) in rats'respiratory tract. To study the influence of LPS and inhaling nitric oxide on the distribution of TLR4.【Method】Thirty-six Sprague-Dawley rats were randomly divided into six groups. Group N: normal control group; Group L: LPS instilled intratracheally to induce ALI; Group Za: LPS + inhaled NO 10 ppm; Group Zb: LPS + inhaled NO 20 ppm; Group Zc: LPS + inhaled NO 40 ppm; And Group Zd: LPS + inhaled NO 100 ppm. At 6 hours after LPS instillation. Lung morphology was studied. TLR4 were detected by immunohistochemistry and Fluorescent Quantitative PCR(FQ-PCR).【Result】The result of immunohistochemistry and FQ-PCR showed that TLR4 distributed widely in common rats'respiratory tract. In the group of ALI(Group L), the inflammation in bronchus and bronchioles was more apparently than the control group in morphology. And the expression of TLR4 was reinforced in main bronchus and bronchioles. In the Group Zb, the inflammation was lightened and the expression of TLR4 decreased as compared with the group of model(Group L).【Conclusion】TLR4 distributes widely in rats'respiratory tract. The stimulation of LPS can reinforce the expression of TLR4. Inhaling low level of nitric oxide(20 ppm) can reduce the increase of TLR4 induced by LPS in bronchioles.