Proteomics Identifies TRAP5 as a Candidate Marker of Residual Inflammation After Optimal Pulse Technology in Experimental Meibomian Gland Dysfunction

Purpose: To determine whether residual clinical, tissue-level, and molecular abnormalities persist after optimal pulse technology (OPT) in experimental meibomian gland dysfunction (MGD), and to identify candidate proteins associated with the post-treatment state. Methods: MGD was induced in rabbits by complete Freund's adjuvant injection into the eyelid margin and palpebral conjunctiva. Animals were assigned to control, MGD, and MGD + OPT groups. Eyelid margin abnormalities were scored from standardized photographs. Histopathologic changes were assessed by hematoxylin and eosin staining, and lipid-related abnormalities were evaluated by oil red O staining. Remaining eyelid tissues were analyzed by label-free quantitative proteomics and pathway enrichment. TRAP5 was further assessed in RAW264.7 macrophages as an exploratory in vitro model. Results: OPT partially improved eyelid margin abnormalities and reduced histopathologic inflammation and structural changes, but the MGD + OPT group did not fully return to control levels. Oil red O staining showed persistent lipid-related abnormalities. Proteomics showed that MGD + OPT tissues remained distinct from control tissues, with residual immune-, metabolic-, extracellular matrix-, and signaling-related changes. TRAP5 remained markedly elevated after OPT and was prioritized as a proteomics-derived candidate molecule. In RAW264.7 cells, TRAP5 modulation was associated with changes in TLR4 and MYD88 protein levels. Conclusions: OPT produced partial but incomplete recovery in experimental MGD. Proteomics identified a residual post-treatment molecular signature and highlighted TRAP5 as a candidate molecule for future tissue-level validation and mechanistic investigation.