| ALI(Acute Lung Injury),the early and mild phase of ARDS,is a syndrome mainly manifested in acute respiratory failure,which is caused by etiological factors except heart diseases.With the characteristics of rapid onset,progress fast,life-threatening and limited effect gained from breathing support and drug therapy,ALI has attracted more and more researches dedicated themselves to this field.Studies indicated that curculigoside posses the ability to modulate inflammatory status and oxidative stress,thus it may exert prevention effect against ALI manifested with overwhelming inflammatory and oxidative stress response.In this study,acute lung injury model of rats was established by intratracheal instillation of LPS,and this model was subsequently used in the study of the prevention effect of curculigoside,a mainly effective component isolated from Curculigo orchioides Gaertn.,against acute lung injury.Our study was mainly focused on two aspects.One was focused on the optimization of extraction and HPLC analysis of curculigoside,the other aspect was focused on the exploration of biological effects of curculigoside against the emerging of ALI,and tried to uncover the mechanisms under it from inflammation and oxidative stress.The major findings are listed below.(1)A systemic study about different single factor—including extraction methods,the kinds of extraction reagents,extraction time,solid-to-liquid ratio and the concentration of extraction reagents—was studied separately to obtain the best extraction process.After that,orthogonal experimental design including 3 factors and 3 levels was employed to further search the best extraction process.The best extraction parameters of curculigoside extracting from Curculigo orchioides Gaertn.was obtained as follows: methanol concentration 80% as the extraction solvent of reflux,3 h,solid-liquid ration 1: 50(g/mL).Under this process,the extraction rates of of curculigoside reached 0.244%.In addition,the HPLC detection process of curculigoside was established.Under the developed detection methods,the chromatograms exhibits the characteristics of smooth baseline,symmetry peak,and has advantages of good precision,stability,repeatability,and a high recovery.The extraction conditions and HPLC method developed not only can provide experimental data for the extraction process and quality control of Curculigo orchioides Gaertn.,but also lay the foundation for the purification of curculigoside extracting from Curculigo orchioides Gaertn.(2)Acute lung injury model of rats was established by intratracheal instillation of LPS,To confirm the eligibility of the acute lung injury model,the assessment was conducted centers on the pathological change,lung injury score,protein concentration and the number of inflammatory cells in BALF.Results showed the acute lung injury model we established was successful.(3)A total of 24 rats(180-220 g weight)were randomly classified into four group(n=6): Sham group,LPS group,LPS+40 mg/kg curculigoside group,LPS+80 mg/kg curculigoside group.Before intratracheal instillation of LPS,rats in curculigoside groups were administered orally per day for five days consecutively.While rats in the Sham and LPS group were replaced with the solvent contains no curculigoside.Rat were anaesthetized at a dose of 30 mg/kg pentobarbital sodium 2 hours after the last administration.Subsequently rats in LPS group and the two groups of curculigoside were instilled via trachea with LPS(4 mg/kg),rats in sham group used physiological saline replaced.Neck skin was sutured to avoid infection.Carotid artery blood were collected for blood gas analysis,then rats were sacrificed to collect bronchoalveolar lavage fluid(BALF)for the counting of inflammation cells and detection of protein and interleukin-6(IL-6)concentration.The activity of myeloperoxidase(MPO),superoxide dismutase(SOD),catalase(CAT)were also detected in the lungs.Results showed that: 1)Compared with sham group,curculigoside can significantly alleviate the lung injury(P<0.05),80 mg/kg curculigoside can reduce the concentration of protein in BALF(P<0.05).2)Compared with sham group,groups of curculigoside both 40 mg/kg and 80 mg/kg can improve oxygenation index significantly(P<0.05).3)Compared with sham group,groups of curculigoside both 40 mg/kg and 80 mg/kg can enhance the level of MPO,SOD,CAT,and MDA significantly(P<0.05),which indicating curculigoside can exert the prevention effect against ALI through up-regulating the expression of antioxidant enzymes,and down-regulating the production of reactive oxygen species.4)Compared with sham group,groups of curculigoside at the dose of 80 mg/kg can significantly decrease the total cell number in BALF(P<0.05),groups both high and low dose of curculigoside can reduce the number of neutrophils and lymphocytes in BALF(P<0.05),indicating curculigoside possess the ability to ameliorate the infiltration of inflammation cells and the release of IL-6.In summary,our findings found that curculigoside can exert the prevention effect against ALI by reducing inflammation and oxidative stress. |
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