Protective Effect Of Tetramethylpyrazine On Acute Lung Injury By Liopolysaccharide In Rats

Objective: To investigate the signal transmission functions damaging vascular barrierand the effects of tetramethylpyrazine on acute lung injury by LPS.Methods:24adult health Wistar rats were randomly divided into four groups: controlgroup,LPS group,TMPâ… ,TMPâ…¡.â‘ LPS groups: Intraperitoneal injection of LPS (1mg/kg) after16hours, rats were treated by intratracheal instillation of LPS (3mg/kg),and the ALI rat models were established.â‘¡TMPâ… group: After establishing the modelof ALI, rats were treated with TMP(40mg/kg) for the prevention and treatment.â‘¢TMPâ…¡group: After establishing the model of ALI, rats were treated withTMP(80mg/kg) for the prevention and treatment.â‘£c ontrol group:Rats were injectedwith normal saline instead of LPS and TMP. Intratracheal injections of LPS3hours later,rats were killed. The lung pathological sections were stained with hematoxylin andeosin. Then the pathological changes were observed under light microscope. Lungwet/dry ratios were measured after wet weight and dry weight examined, respectively.10%lung tissues were made to measure myeloperoxidase(MPO) activity andmalonyldialdehyde (MDA) level by assay kits. The expression of RhoA,ROCK2andp-MLC proteins were analyzed by westernblot. The expression of RhoA,ROCK2mRNA were analyzed by real-time PCR.Results: Compared with the control group, pulmonary interstitial edema, infiltrationand activation of inflammation cells could be seen and the wet/dry lung weight ratio andthe percentage of neutrophils and the levels of MDA and MPO were all significantlyincreased In LPS group (P<0.01). The expression of RhoA,ROCK2mRNA and theexpression of RhoA,ROCK2protein were also increased in LPS groups(P<0.01).Tetramethylpyrazine groups attenuated the exudation degree of edema andinflammatory and the increase in wet/dry lung weight ratio (P<0.05). They alsoinhibited the production of MDA and the activity of MPO and lowered the expression ofp-MLC protein and RhoA, ROCK2mRNA and proteins (P<0.05). Conclusion: The Rho/ROCK pathway plays an important role in acute rat lung injuryinduced by lipopolysaccharide. Tetramethylpyrazine protected against LPS-inducedacute lung injury in rats by inhibiting the expression of RhoA,ROCK2and p-MLCmRNA and proteins.