| Objective:To investigate the expression of IL-17and the effects of early application of low-dose dexamethasone (lmg/kg) in rats with acute lung injury induced by lipopolysaccharideMethods:Forty-eight adult healthy SD rats were randomly divided into three groups:normal controls group(group C), acute lung injury induced by LPS group (group ALI)and dexamethasone group(group D).To form ALI model in rats,5mg/kg of LPS were injected into rats by intraperitoneal.Immediately1mg/kg of dexamethasone were injected into rats by intraperitoneal to form group D, equal doses of normal saline were injected into rats in group C by intraperitoneal.At2h,6h two time points,8rats from each group were killed.Both left BALF and right lung tissue were obtained to measure wet to dry weight ratio (W/D),the levels of IL-17and TNF-a in BALF by ELISA,and the histopathology was aslo performed.Results:1IL-17:BALF contents:compared with group C,the content of IL-17had no significant difference at2h in group ALI,but it increased sharply at6h,the difference between two groups was statistically significant (P<0.05);in group D,the content of IL-17had no significant difference at2h compared with group C and group ALI;it decreased at6h compared with group ALI,but still higher than the group C,compared with the other two groups were statistically significant (P<0.05).2TNF-α BALF contents:compared with group C,the content of TNF-α was significantly increased in group ALI, and increased with time, the difference was statistically significant (P<0.05);it decreased compared with group ALI,but still higher than the group C,compared with the other two groups were statistically significant (P<0.05).3lung W/D:group C,the difference was not statistically significant at two time points;group ALI was significantly higher compared with group C at each time point,and the difference was significantly (P<0.05);in group D,it decreased significantly compared with group ALI,but still higher than the group C.4Histopathology changes in lung tissue:group ALI with varying degrees of swelling of the lungs appear congestion, scattered severe bleeding; optical microscopy shows diffuse alveolar septal thickening, some alveolar collapse, interstitial diffuse pulmonary hemorrhage, alveolar shows a large number of inflammatory cell infiltration and exudate. Group D,lung congestion and swelling, inflammatory cell infiltration and alveolar exudate, alveolar septal thickening and the degree of alveolar collapse was significantly reduced compared with ALI.Conclusion:.IL-17is involved in Rat ALI process induced by LPS,and it expresses significantly at6h.Early application of small dose dexamethasone reduces the BALF expression of IL-17in rat model of ALI,and it may be another mechanism through which dexamethasone attenuates ALI. |
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