Topical use of Nerve Growth Factor on ocular flora and cytology in dogs eye surface

Purpose To investigate if topical Nerve Growth Factor (NGF) affects the ocular flora and to study corneal conjunctival cytology in dogs with different eye surface disease. Methods The present study has been conducted on 9 dogs (18 eyes) affected by different ocular surface disease. The dogs were various ages (from 2 to 10 years old) and different sexes (5 males ‐ 4 females). 6 dogs were affected by dry eye, 1 had a superficial keratitis and 2 dogs had a cornea ulcer. All dogs underwent the following examinations: cornea evaluation by slit lamp, fluorescent staining, Schirmer tear test I (STT I), corneal and conjunctival cytology. All samples made with ocular swabs were placed in a sterile blood agar. 6 dogs showed no bacteria, 3 dogs displayed Staphylococcus spp. Cytology pointed out many inflammatory cells. The dogs were topically treated with purified murine NGF diluted in paraffin oil (200 microg/ml) for 4 weeks (50 microg every 12 h). Results The result revealed that all swabs were sterile, while the cytology analysis showed a significant reduction in the number of corneal inflammatory cells. This latter observation is related to a decrease of the corneal inflammatory reduction. Conclusion This report demonstrated that NGF exerts an antibacterial and anti inflammatory activity that confirmed and extended previous evidences on NGF research. Moreover, our results suggest a potential therapeutic use of NGF in dogs with different ocular inflammatory surface. However, further clinical studies need to be done to assess the consistency of this clinic approach.