Abstract
Objective:To elucidate the implications of L-carnosine on interleukin-1 alpha (IL-1 alpha)-induced inflammation of lacrimal glands (LGs).
Materials and methods: Forty rabbits were divided equally into four groups: control group (G1), IL-1 alpha (G2), L-carnosine (G3), and L-carnosine plus IL-1 alpha (G4). Several clinical, histopathological, immunohistochemical, morphometric, and biochemical investigations were performed, followed by statistical analysis to diagnose the presence of dry eye disease (DED).
Results: The LGs of G2 rabbits showed degeneration of the acinar cells, increased deposition of collagen fibers, and marked immunoexpression of FasL; elevated levels of interferon-gamma, tumor necrosis factor-alpha, transforming growth factor-beta 1, and malondialdehyde; and decreased levels of glutathione peroxidase, superoxide dismutase, catalase, and reactive oxygen species compared with those of G1 rabbits. In contrast, administration of L-carnosine to G4 rabbits revealed marked improvement of all previously harmful changes in G2 rabbits, indicating the cytoprotective effects of L-carnosine against IL-1 alpha-induced inflammation of LGs.
Conclusions: IL-1 alpha induced inflammation of LGs and eye dryness via oxidative stress, proinflammatory, apoptotic, and profibrotic effects, whereas L-carnosine mitigated DED through antioxidant, anti-inflammatory, antiapoptotic, and antifibrotic effects on LGs. Therefore, this work demonstrates for the first time that L-carnosine may be used as adjuvant therapy for the preservation of visual integrity in patients with DED.