Modified Autologous Conditioned Serum (mACS) demonstrates the neuroprotective effect in the Benzalkonium chloride (BAK)-induced murine dry eye model

The purpose of this study was to analyze and compare cytokine and growth factor levels in modified autologous conditioned serum (mACS) and autologous serum (AS) and to evaluate their therapeutic effects in a benzalkonium chloride (BAK)-induced murine dry eye model. Serum samples were obtained from twenty healthy volunteers and analyzed by ELISA. A dry eye model was established in twenty-four C57BL/6 mice by topical application of 0.2% BAK twice daily for seven days. The mice were evenly divided into three subgroups: saline-treated, 0.5% AS-treated, and 0.5% mACS-treated. The right eyes were treated, and the left eyes served as untreated controls. Eyeballs were harvested on days 7 and 14 for immunofluorescence staining. Results showed that neuroprotective factors (BDNF and fractalkine), pro-inflammatory cytokines (IL-1β, IL-6, MIF, TNF-α), and VEGF-A were significantly elevated in the mACS group, whereas PDGF-BB was significantly reduced. Furthermore, immunofluorescence analysis demonstrated a significantly greater recovery of central corneal nerve fibers in the mACS-treated group compared with the saline group at day 7 (p < 0.01). At day 14, the mACS-treated group continued to show a trend toward increased central corneal nerve regeneration, although this difference did not reach conventional statistical significance (p < 0.1). No significant differences were observed between the AS- and saline-treated groups. In conclusion, compared with AS, mACS demonstrates a cytokine profile suggestive of enhanced neuroprotective potential and may facilitate corneal nerve regeneration in the BAK-induced murine dry eye model.