Figure 1.

In vitro effects of HCl and mechanical stretch on cellular morphology and epithelial mesenchymal transition (EMT). (A) Schematic of mechanical stretch and HCl injury model in BEAS-2B cells. Cells were cultured and subjected to HCl stimulation followed by mechanical stretch using the Flexcell FX500T cell strain loading system. (B) Representative phase-contrast images showing morphological changes (spindle shape, intercellular spacing) under different conditions: control (PBS), HCl stimulation, stretch, and HCl + stretch. (C) Western blot analysis of E-cadherin, Vimentin, and α-SMA protein expression in control (PBS), stretch, and HCl-treated cells with or without stretch. GAPDH served as a loading control. (D-F) Quantification of E-cadherin (epithelial marker), Vimentin, and α-SMA (mesenchymal markers) expression levels normalized to GAPDH. Data are presented as mean ± SEM. n = 4 /group. (G) Immunofluorescence staining for E-cadherin (green), Vimentin (red), and α-SMA (red) in control (PBS), stretch, and HCl-treated cells with or without stretch. Nuclei were counterstained with DAPI (blue). (H) Western blot analysis of PTEN protein expression in control (PBS) and HCl + stretched cells. GAPDH served as a loading control. (I) Quantification of PTEN expression levels normalized to GAPDH. Data are presented as mean ± SEM. n = 4 /group. Comparisons between two groups were performed using independent sample t tests. One-way ANOVA and the Bonferroni post hoc test were used to compare more than two groups. Not significant (ns): P > 0.05, *: P < 0.05, **: P < 0.01, ***: P < 0.001, ****: P < 0.0001.