Objective To investigate the mechanisms of microRNA-211-5p (miR-211-5p) in regulation of proliferation, apoptosis, migration, invasion, and collagen synthesis of human hypertrophic scar fibroblasts (HSFBs) via the transforming growth factor (TGF)-β1/Smad homolog 2 (Smad2) signaling pathway.

Methods HSFBs were randomly divided into control, miR-NC, miR-211-5p mimic, anti-miR-211-5p, and miR-211-5p mimic + SB431542 (TGF-β1/Smad2 signaling pathway inhibitor) groups. After 72 hours of continuous culture, quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) was used to detect miR-211-5p expression, western blot was employed to assess TGF-β1 and Smad2 protein levels, methyl-thiazoldiphenyl-tetrazolium (MTT) assay was performed to measure cell proliferation, flow cytometry was utilized to analyze apoptosis rates, Transwell chambers were applied to evaluate cell invasion and migration, and western blot was again utilized to quantify type I collagen (Col-Ⅰ) and type Ⅲ collagen (Col-Ⅲ) protein expressions. An animal model of hypertrophic scars was established in rats using a constant temperature and pressure electric scalding apparatus. Following successful modeling, rats in each group received tail vein injections of miR-NC or miR-211-5p mimic. Scar healing was assessed, and histopathological changes in scar tissue were observed via hematoxylin and eosin (HE) staining.

Results Compared with the control and miR-NC groups, the miR-211-5p mimic group exhibited increased miR-211-5p, TGF-β1, and Smad2 protein expressions, enhanced cell proliferation, reduced invasion and migration capabilities, decreased apoptosis rates, and elevated Col-Ⅰ and Col-Ⅲ protein expressions (P < 0.05). Conversely, the anti-miR-211-5p group displayed opposite trends, and significant differences were observed between the anti-miR-211-5p and miR-211-5p mimic groups for the aforementioned indicators (P < 0.05). Compared to the miR-NC group, the miR-211-5p mimic group had higher scar healing rates and fibroblast counts (P < 0.05). Compared to the miR-211-5p mimic group, the miR-211-5p mimic + SB431542 group showed reduced TGF-β1, Smad2 protein expressions, and weakened cell invasion and migration capabilities (P < 0.05).

Conclusion MiR-211-5p may regulate proliferation, apoptosis, migration, invasion, and collagen synthesis of HSFBs by activating the TGF-β1/Smad2 signaling pathway.