Bletilla striata polysaccharides promote the proliferation and migration of human gingival fibroblasts on titanium surfaces via the PI3K/AKT pathway: a preliminary in vitro study

To investigate the effects of Bletilla striata polysaccharides (BSPs) on the proliferation and migration of human gingival fibroblasts (HGFs) on titanium surfaces and clarify the regulatory role of the PI3K/AKT signaling pathway. Primary HGFs were isolated from healthy gingival tissues and subjected to hematoxylin‒eosin (HE) staining and immunofluorescence (purity ≥ 95%). HGFs were cocultured with titanium sheets and divided into control, BSP (800 µg/mL, optimal concentration), and BSP + wortmannin (WM, PI3K inhibitor) groups. Cell proliferation was evaluated by a CCK-8 assay, live/dead staining, and quantitative real-time PCR (qRT‒PCR) for Ki67 and PCNA mRNA expression. Cell migration was detected by scratch wound healing and Transwell assays. ELISA was used to measure the secretion of fibronectin (FN) and type I collagen (COLI) in the culture medium. Scanning electron microscopy (SEM) was used to observe the cell morphology on the titanium surfaces. HE staining and immunofluorescence confirmed the successful isolation and identification of HGFs. BSPs significantly promoted HGF proliferation, as evidenced by increased CCK-8 absorbance, a higher live cell ratio, an increased proportion of Ki67/PCNA double-positive cells, and increased mRNA and protein expression levels of Ki67 and PCNA (P < 0.01). Scratch and Transwell assays revealed that BSPs enhanced HGF migratory capacity, accompanied by increased secretion of FN and COLI (P < 0.01). SEM revealed that BSPs improved cell spreading and surface coverage on titanium. Mechanistically, BSPs activated the PI3K/AKT pathway, and WM cotreatment abolished both the pathway activation and the proproliferative and promigratory effects of BSPs. BSPs promote the proliferation and migration of HGFs on titanium surfaces by activating the PI3K/AKT signaling pathway, which is associated with the upregulation of Ki67 and PCNA expression and increased FN and COLI secretion. This study provides experimental evidence for the potential application of BSPs as bioactive agents in peri-implant soft tissue regeneration, but these findings require further in vivo validation.