ABSTRACT
Objective To investigate the protective effects of imipramine on alveolar epithelial barrier functiou in mice against LPS-induced acute lung injury (ALI),and explore the possible mechanisms.Methods Total of 32 SPF male Balb/c mice were randomly (random number) divided into four groups:control group,Imipramine group,LPS group,LPS + Imipramine group.To establish an animal model of ALI,mice were administered intraperitoneally with LPS in 20 mg/kg.Mice were treated with imipramine in 25 mg/kg 30 min prior to LPS administration.FITC-FD4 was administered in mice via the tail vein with FITC-FD4 10 min before mice sacrificed under anesthesia at 12 hours after LPS administration,then bronchoalveolar lavage fluid (BALF) and lung tissue were obtained.HE staining was used to observe histopathological changes,and pathology scores;lung tissue wet-to-dry weight ratio and BALF/serum FD4 ratio were used to assess pulmonary edema and alveolar epithelial permeability.Real-time PCR,western blot and immunochemistry were employed to detect the mRNA expressions and protein levels of Occludin,Claudin-4 and ZO-1.Data were analyzed with SPSS 16.0 software,one way analysis of variance (ANOVA) was used to compare multiple sets of variables,the intergroup comparisons were analyzed by the least-significant-difference (LSD) tests with P ＜ 0.05 for the statistically significant difference.Results Compared with LPS group,LPS + lmipramine group had a statistically significant decrease in pathological score [(9.22 ± 0.21) vs.(11.23 ± O.55),P ＜ O.05);the wet-to-dry weight ratio in LPS + Imipramine group was less than that in LPS group and the difference was statistically significant (P ＜ 0.05);compared with LPS group,the ratio of BALF/serum FD4 in LPS + Imipramine was less and the difference was statistically significant (P ＜ 0.05);compared with LPS group,the mRNA expressions and protein levels of Occludin,Claudin-4 and ZO-1 in LPS + Imipramine group were significantly increased (mRNA:Occludin:P ＜ 0.05;Claudin-4:P ＜ 0.05;ZO-1:P ＜ 0.05 . western blot:Occludin:P ＜ 0.05;Claudin-4:P ＜ 0.05;ZO-1:P ＜ 0.05).Immunochemistry showed that Occludin and Claudin-4 were present mainly in alveolar epithelial cell membrane,Z0-1 was found mainly in cytoplasm of alveolar epithelial cell.In control group and Imipramine group,tight junction proteins were obviously expressed.Compared with control group,protein levels in LPS group were significantly decreased (Occludin:P ＜ 0.05;Claudin-4:P ＜ 0.05;ZO-1:t =6.59,P ＜ 0.05);compared with LPS group,the tight junction proteins in LPS + Imipramine group were significantly increased (Occludin:P ＜ 0.05;Claudin-4:P ＜ 0.05;ZO-1:P ＜ 0.05).Conclusion The protective effects of imipramine on alveolar epithelial barrier function by up-regulating tight junction proteins expression in murine LPS-induced ALI.
ABSTRACT
Aim To explore the effect of pemetrexed on autophagy and the function of autohpagy activation in A549 cells.Methods The anti-proliferative effect of pemetrexed on A549 cells was detected by MTS. The formation of autophagosome was observed by trans-mission electron microscopy (TEM)and the expression of autophagy-related proteins was determined by West-ern blot.The inhibitory effects of the combination of pemetrexed and a selective autophagy inhibitor on A549 cells were measured by MTS.Results Peme-trexed inhibited the proliferation of A549 cells.Auto-phagy was activated in A549 cells by exposure to pemtrexed.Autophagosome was increased in peme-trexed treatment cells compared with control group. Pemtrexed treatment led to the formation of autophago-some and the conversion of LC3-Ⅰto LC3-Ⅱ.The in-crease of Beclin-1 and the decline of autophagy sub-strate of p62 were observed in pemtrexed treated A549 cells.The pharmacological autophagy inhibitor chloro-quine (CQ)sensitized A549 cells to pemetrexed treat-ment.The inhibitory rate was (28.42 ±2.45 )% for pemetrexed only,and (45 .36 ±3.52 )% for peme-trexed combined with CQ.Conclusions Pemetrexed could activate autophagy in A549 cell lines.The dis-ruption of autophagy facilitates the anti-proliferative effect of pemetrexed on A549 cells,which provides a novel strategy in lung cancer treatment.