Topical cyclodextrin minocycline inclusion complex inhibited the inflammation in blepharitis-related dry eye disease

Blepharitis-related dry eye disease (BRDED) is a common disease characterized by the palpebral margin inflammation and the blindness-causing changes in the ocular surface. Oral administration of minocycline (MI) can effectively treat blepharitis. However, long-term oral administration has side effects. And topical MI for ocular surface disorders is restricted because of its poor solubility and stability. Therefore, we aimed to evaluate the effects of a topical cyclodextrin-minocycline inclusion complex (CCH/MI) on BRDED. We further aimed to elucidate the mechanisms underlying these effects. A cyclodextrin polymer (CCH) was loaded with MI to form a CCH/MI. The anti-inflammatory effects of MI were then evaluated using immunofluorescence staining and western blotting for MMP9, TNF-α, and iNOS expression in human corneal epithelial (HCE-2) cells. A Cell Counting Kit-8 (CCK-8) cytotoxicity assay demonstrated that CCH and CCH/MI was not toxic to HCE-2 and CCL-20.2. Furthermore, CCH/MI reduced the NF-κB p65, p-NF-κB p65, p38 MAPK, p-p38 MAPK, MMP-9, MMP-2, TNF-α, and iNOS expression induced by lipopolysaccharide (LPS) in HCE-2 cells. CCH/MI inhibited the expression of proinflammatory proteins in the palpebral margin tissue. In addition, CCH/MI increased tear production, decreased corneal fluorescence staining scores, and improved tear film stability in a rabbit BRDED model. Moreover, this complex significantly reduced the number of TUNEL-positive cells. What's more, it increased the mean fluorescence intensity of PPAR-γ staining and the number of PAS-positive cells. Overall, topic MI demonstrated excellent anti-inflammation properties and promoted the restoration of ocular surface homeostasis in BRDED. These findings demonstrated that CCH/MI is a safe and effective treatment strategy for BRDED.