Pathologic Changes And MMP-2、9Expression In Lung Tissue Of Type2Diabetic Mice And Intervention Researches Of Fluorofenidone And Losartan

Objective:To investigate pathologic changes and MMP-2、9expression in lung tissue of type2diabetic db/db mice and to evaluate the treatment of fluorofenidone (AKF-PD) and losartan(LOS) in lung fibrosis of diabetic mice, and to compare therapeutic efficacy between LOS and AKF-PD and explore their possible mechanism.Method:Male db/db mice and age-matched db/m mice were used in this study. The db/db mice were randomly divided into six groups respectively, each group had6mice:5weeks model group,5weeks AKF-PD treatment group,5weeks LOS treatment group,12weeks model group,12weeks AKF-PD treatment group and12weeks LOS treatment group. The db/db mice were administered drugs by gavage daily at the age of5weeks or12weeks, until24weeks of age. AKF-PD dissolved in carboxymethylcellulose sodium solution, at doses of500mg·body weight-1·day-1. LOS was administered daily at doses of20mg·body weights-1·day-1. The db/db model mice and the db/m mice were administered the same amount of CMCNa(6.7ml/body weight) by gavage daily. The mice were weighed every2-4days during the experiment, and levels of blood glucose from tail vein were determined at the beginning and end of intervention. All mice were sacrificed at the age of24weeks. The pathologic changes of lung were observed by HE staining、Masson trichrome staining, and the expression levels of MMP-2,9in the lung were detected by immunohistochemistry.Outcome: 1. Before the intervention, the body weight and the glucose of db/db mice at the age of12weeks compared with the normal control group, the differences were significant(P<0.05). After the intervention, the body weight and the glucose of db/db mice at the age of24weeks were markedly increased, comparing with the normal control group (P<0.01).2. Results of HE staining:The lung structure was clear and complete, alveolar distribution was even, and a small amount of connective tissue in septa was found in the normal control mice. Lung structural disorder, bronchial wall, alveolar wall and lung interstitium with different degrees of thickening, unclear alveolar epithelial cells, inflammatory cells infiltration were found in the model mice. The above changes were reduced in varying degrees in the AKF-PD treatment groups and LOS treatment groups.3. Results of Masson staining:A small amount of collagen fibers were found in the lung interstitium and surrounding blood vessels in the lung of the normal control mice. Increased collagen deposition in interstitium were found in the model mice, more than the normal control mice (P<0.01); Collagen deposition in the5weeks AKF-PD treatment group and the5weeks LOS treatment group were reduced respectively, comparing with the5weeks model group(P<0.05); The deposition of collagen in the5week AKF-PD treatment group was decreased (P<0.05), comparing with the5weeks LOS treatment group; The expression of collagen in the12weeks AKF-PD treatment group was decreased (P<0.01), comparing with the12weeks model group; The collagen deposition of the5weeks AKF-PD treatment group was decreased compared with the12weeks AKF-PD treatment group (P<0.05).4. Results of immunohistochemistry:(1) MMP-2immunohisto-chemical results:Weak positive expression was found in the normal control mice. The expression of positive granules in the model mice was increased, more than the normal control mice(P<0.01); MMP-2expression of lung tissue was decreased in the5weeks AKF-PD treatment group and the5weeks LOS treatment group respectively, comparing with the5weeks model group (P<0.05); MMP-2expression of the5weeks AKF-PD group was reduced, comparing with the5weeks LOS treatment group(P<0.05); MMP-2expression of the12weeks AKF-PD treatment group also was decreased comparing with the12weeks model group(P<0.05).(2) MMP-9immunohistochemical results: Weak positive expression was found in the normal control mice. The expression of positive granules in the model mice was increased, more than the normal control mice(P<0.01); MMP-9expression of lung tissue was decreased in the5weeks AKF-PD treatment group and the5weeks LOS treatment group respectively, comparing with the5weeks model group (P<0.01); MMP-9expression of the12week AKF-PD treatment group also was decreased comparing with the12weeks model group(P<0.01).Conclusion:1. The lung tissue of diabetic mice showed pulmonary interstitial fibrosis.2. The abnormal expression of MMP-2、9in the lung tissue of diabetic mice suggested their involvement in the pathogenesis of diabetic lung fibrosis.3. Fluorofenidone and losartan could alleviate diabetic lung fibrosis in mice and which may be related to the inhibition of MMP-2,9expression in lung tissue. Fluorofenidone had better effect than losartan.4. The early treatment of fluorofenidone had better inhibition of MMP-2expression and relieved diabetic lung fibrosis in mice.