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

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.

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.

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.

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.