Effect of Antiseptic Irrigation Solutions on Primary Human Knee Fibroblasts Cultured in Human Platelet Lysate

Background: Native and periprosthetic joint infections are devastating conditions fraught with patient morbidity and mortality. Aseptic and septic joints are often debrided and irrigated to decrease bacterial loads when preventing or treating infection. However, the effect of clinically used irrigation solutions on the native cellular components of the synovial joint is unknown.

Methods: Patients consented, and their suprapatellar knee tissue was surgically excised for fibroblast isolation. Cultured knee fibroblasts were treated with normal saline for three minutes or one of the following experimental solutions: acetic acid, chlorhexidine-gluconate, Dakin's solution, hydrogen peroxide, or povidone-iodine. The exposure time for the antiseptic solutions was one and three minutes. At 24 hours after irrigation treatment, metabolic activity was measured via MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium] activity assay, and deoxyribonucleic acid (DNA) content was assessed by Hoechst staining as a surrogate for cell number. Phase-contrast imaging elucidated proliferation potential, progressive cell loss, and cell morphology over a 5-day period. All experiments were repeated in triplicate.

Results: All experimental antiseptic irrigation solutions, regardless of application time, caused a significant reduction in metabolic activity and DNA content, indicating extensive cell death. Phase-contrast imaging showed halted cellular proliferation, progressive cell loss, and distinct changes in cellular morphology, indicating decreased cellular viability and progressive cell death.

Conclusions: All antiseptic irrigation solutions investigated in this study were severely cytotoxic to human knee fibroblasts regardless of their chemical composition. The concentrations of these solutions are commonly used in orthopaedic surgery. Although these solutions have high bactericidal properties, it may be beneficial to use them in combination at lower doses to retain their effect on bacteria while remaining benign to native synovial cells.