Abstract
BACKGROUND AND AIM: Keratoconjunctivitis sicca (KCS) is a chronic inflammatory condition of the canine ocular surface primarily caused by immune-mediated destruction of lacrimal tissues. Platelet-rich plasma (PRP) is known for its regenerative and anti-inflammatory properties, while omega-3 (ω-3) fatty acids possess immunomodulatory effects. This study aimed to evaluate the efficacy of injectable homologous PRP (HPRP), alone or in combination with oral ω-3 supplementation, in improving clinical and histopathological parameters in dogs with KCS. MATERIALS AND METHODS: Twenty-two dogs (44 eyes) with bilateral KCS were randomized into two treatment groups: HPRP (n = 22 eyes) and HPRP plus oral ω-3 (HPRPO; n = 22 eyes). Treatments were administered monthly for up to three sessions alongside topical lubricants. Ophthalmological evaluations - including Schirmer's tear test-1 (STT-1), tear film breakup time (TBUT), fluorescein staining, cytology of the third eyelid gland, and conjunctival histopathology - were performed at baseline and at monthly intervals up to 6 months. RESULTS: Both groups demonstrated significant improvement in ocular clinical signs and tear secretion. STT-1 values significantly increased from baseline in both groups (p < 0.05), without significant intergroup differences. However, TBUT values were significantly higher in the HPRPO group from month 3 onwards (p < 0.05). Cytological and histological analyses revealed a significant reduction in lymphocyte and neutrophil counts and an increase in goblet cell numbers in both groups, with greater improvement in the HPRPO group (p < 0.05). Earlier resolution of corneal ulcers and reduced ocular inflammation were observed in the HPRPO group. CONCLUSION: Injectable HPRP, particularly when combined with oral ω-3 supplementation, is an effective therapeutic modality for managing KCS in dogs. The combination therapy enhanced tear film stability, reduced ocular inflammation, and promoted epithelial repair more effectively than HPRP alone. These findings support the synergistic effect of ω-3 fatty acids with PRP in ocular surface restoration.