The molecular weight of hyaluronic acid influences metabolic activity and osteogenic differentiation of periodontal ligament cells

OBJECTIVE: While HA is present naturally in periodontal tissues, its molecular weight can vary widely in vivo. The objective of this study was to directly compare the biological reactions of periodontal ligament cells to four distinct molecular weights of hyaluronic acid (HA). MATERIALS AND METHODS: Immortalized human periodontal ligament cells (PDL-hTERT) were cultured for 21 days in culture medium alone (control) or enriched with osteogenic supplements (OS group). Other 4 experimental groups were cultured in OS medium with the addition of HA with different molecular weights (HMW, MMW, LMW, and ULMW). The cell morphology was examined daily. WST1 assays were performed to evaluate metabolic activity. Von Kossa staining and calcium deposition assay were used to analyze osteogenic differentiation and mineralization. RESULTS: Cell morphology remained unaltered in all groups. Cells stimulated with OS alone or with the addition of hyaluronan showed all the typical microscopic appearance of osteogenic differentiation. Metabolic activity increased in all groups over time. Hyaluronan stimulated greater metabolic activity than the control group, with LMW HA and MMW HA showing the most significant increase. All groups showed mineral deposits and calcium deposition after 21 days of stimulation. CONCLUSION: Our results suggest that hyaluronan can promote metabolic activity and mineralization of PDL-hTERT cells, with LMW HA being the most effective. CLINICAL RELEVANCE: These results shed light on how the various molecular weight fractions of HA promote tissue regeneration and repair, as well as help to identify an optimal molecular weight range for this application in periodontal tissues.