In Vitro Model Exploring the Mechanisms of Dextrose Prolotherapy: Fibroblasts Exposed to Clinical Concentrations of Dextrose Exhibit Significant Rebound Effects 48 Hours After Exposure

ObjectiveHypertonic injection of dextrose is an alternative treatment for reducing pain and increasing function in patients with knee osteoarthritis (OA). Dextrose prolotherapy (DP) is hypothesized to induce localized inflammation, leading to proliferation of cells in the joint space. This in vitro study explores how exposure to therapeutic doses of hypertonic dextrose affects fibroblast viability and proliferation, either directly or indirectly through exposure to secreted factors by dextrose-treated cells.DesignMRC-5 fibroblasts exposed for 15 to 120 minutes to dextrose solutions at concentrations of 5%, 10%, 15%, 20%, or 25% were compared to a media-only control. Metabolic activity was measured by the XTT assay as an indicator of cell viability and proliferation.ResultsFibroblasts exposed for any length of time at the highest concentration of dextrose (25%) or lower concentrations (10-20%) for longer durations exhibited significant reductions in cell viability compared to media controls. However, fibroblasts exposed to higher concentrations of dextrose (15-25%) for shorter durations (30-60 min) or lower concentrations (10%) for longer durations (120 min) exhibit an increased proliferative effect 48 hours after the initial experiment. Nascent fibroblasts exposed to supernatant fluid from cells directly treated with dextrose did not have a negative impact on cell viability compared to the media control.ConclusionsThese results suggest dextrose concentrations used for prolotherapy may stimulate proliferative responses in fibroblasts in support of theorized mechanisms of DP.