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Objective To explore the impact of macrophage-to-myofibroblast transition (MMT) on pulmonary fibrosis induced by acute lung injury by LPS. Methods Totally 21 male mice were randomly classified into 7 groups: control group, model group (LPS-PF) at different time points and intervention group of clodronate-liposomes (CL-LIP)treatement at different time points(n=3). Pulmonary fibrosis was identified by HE and Masson staining microscopy. The immuno-fluorescence technology was used for the evaluation of numbers of macrophage- to- myofibroblast transition cells (MMT cell which co-expressed CD68 and α-SMA). Bone marrow-derived macrophages (BMDMs) were randomly classified into two group: control (Ctrl) group and TGF-β1-treated group induced by transforming growthfactor-β1. α-SMA, FN and Col1 were detected by RT-qPCR. The expression of α-SMA, Smad3 and p-Smad3 protein was evaluated by Western blot. Results At day 7, the Ashcroft score of lung tissue in LPS-PF mouse model was significantly increased when compared with the Ctrl group (P＜0.01); While the score significantly declined when the model was pretreated with CL-LIP (P＜0.05). As detected by immuno-fluorescence staining, in CL-LIP group the number of CD68-positive cells co-labeled with α-SMA was obviously less then that of LPS-PF group of the corresponding time point(P＜0.01). When the BMDMs were stimulated by TGF-β1 at 24 h, 48 h and 96 h respectively, a higher expression of α-SMA,FN,Col1, were found in TGF-β1-treated group than that in Ctrl group at the corresponding time point (P＜0.01). The expression of Smad3, p-Smad3 significantly higher in LPS-PF group (at both day 7 and day 10) and TGF-β1-treated group (at both 48 h and 96 h) as compared to corresponding control group (P＜0.01). Conclusions MMT promotes pulmonary fibrosis induced by ALI via LPS. Smad3 is proved to be involved in the MMT process.

According to the latest drilling data, the geologic survey of surrounding outcrops and the laboratory test results of rock samples, this paper studies the regional distribution, geochemical and reservoir characteristics and gas concentration of organic-rich shales to reveal the shale gas generation and potential of the Lower Cambrian Qiongzhusi Formation of the Southern Sichuan Basin. The study area features high organic content (with TOC between 0.55% and 25.7%, average of more than 2%), great net shale thickness (of 60–300 m), high brittle mineral content (over 40%), abundant micro- and nanometer-sized pores and micro-fractures, and high gas content (0.27–6.02 m3/t, average of 1.90 m3/t), which is in favor of the generation and accumulation of shale gas. The Lower Cambrian Qiongzhusi Formation is one of the most favorable strata which has frequent gas show and industrialization breakthrough during drilling, and the Weiyuan and Xunyong-Junlian areas are two most realistic and favorable targets for shale gas exploration and development. Key words: Southern Sichuan Basin, Lower Cambrian, Qiongzhusi Formation, shale gas, accumulation, resource potential