Abstract: Objective To investigate the reparative effect of mesenchymal stem cells (MSCs)overexpressing long intergenic non-coding RNA ( lincRNA) -p21 on acute lung injury ( ALI) inmice. Methods Seventy male C57BL / 6 mice were randomly divided into 7 groups, with n = 10 ineach group. The 7 groups were as follows: sham group, ALI group, MSC + ALI group, p21-MSC + ALI group, empty vector-MSC + ALI group, p21 + ALI group, and empty vector + ALI group. Real-time fluorescence quantitative PCR (qRT-PCR) was used to detect the expression level of lincRNA-p21 in lung tissues of each group. ELISA was used to detect the levels of TNF-α, IL- 1β, IL-8, IL-6, IL-10, IL-13, IL-1Ra, and caspase3 in bronchoalveolar lavage fluid. The effects on arterial blood oxygen pressure ( PaO2 ), lung index ( LI), lung permeability index (LPI), and oxygenation index (OI) were evaluated. Flow cytometry was used to detect and ana
lyze the proportion of apoptotic cells in lung tissues. Western blotting was used to detect the expression levels of Bcl-2, Bax, caspase3, and cleaved-caspase3 in lung tissues. Results The levels of lincRNA-p21, IL-10, IL-13, IL-1Ra, Bcl-2, and the values of PaO2 and OI in the ALI group were decreased, while LI, LPI, TNF-α, IL-1β, IL-8, IL-6, Bax, caspase3, cleaved-caspase3 were upregulated, and the proportion of apoptotic cells was increased when compared with those inthe sham group ( all P < 0. 05). The levels of IL-10, IL-13, IL-1Ra, Bcl-2, and the values ofPaO 2and OI were all increased in the MSC + ALI group, and the levels of TNF-α, IL-1β, IL-8, IL-6, Bax, caspase3 and cleaved caspase3, and the values of LI were all decreased when compared with those in the ALI group, the proportion of apoptotic cells was decreased (all P< 0. 05).The expression level of lincRNA-p21 and the value of LPI had no significant change between abovegroups (P > 0. 05). The levels of lincRNA-p21, IL-10, IL-13, IL-1Ra, Bcl-2, and the valuesof PaO 2and OI were increased, while values of LI, LPI, and levels of TNF-α, IL-1β, IL-8, IL- 6, Bax, caspase3, cleaved-caspase3 were decreased, and the proportion of apoptotic cells was decreased in the p21-MSC + ALI group when compared with those in the empty vector-MSC + ALIgroup (all P< 0. 05). The levels of lincRNA-p21, IL-10, IL-13, IL-1Ra, Bcl-2, and the values of PaO 2and OI in the p21 + ALI group were increased (all P < 0. 05), and the levels of TNF-α,IL-1β, IL-8, IL-6, Bax, caspase3, and cleaved caspase3, and the values of LI, LPI were decreased, and the proportion of apoptotic cells was decreased when compared with those in the emptyvector + ALI group (all P< 0. 05). Conclusion MSCs overexpressing lincRNA-p21 have an inhibitory effect on inflammatory injury and lung cell apoptosis in ALI mice.

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