الفهرس 
AcknowledgmentOnly 14 pages are availabe for public view
 |  | from | 125 |  |  |
| | | from | 125 | | |
Abstract
Ulcerative keratitis can have serious consequences in equine, because they are prone to develop secondary mycotic or bacterial infections either from both the ocular surface and the environment. A number of therapeutic strategies have been used that aim to prevent secondary bacterial and fungal infection and enhance reepithelialisation. However, optimal medical therapy remains controversial and not firmly established. The recent interesting regenerative therapies are used for fixing of different pathologies in the ophthalmology field. Recently, blood derivatives have also been described as a treatment for ophthalmology disorders, including persistent corneal epithelial defects. Platelet concentrates are autogenous products prepared through the centrifugation of a blood sample from the patient. The aim of this technique is to collect the most active components from the blood sample – platelets, which are rich in growth factors, fibrin and sometimes leukocytes, in addition to prepare them in a clinically usable form. Platelet-rich fibrin (PRF) is an autologous fibrin-based, living biomaterial, derived from patient’s blood. Advanced platelet rich fibrin (A-PRF) is one of the PRF protocols, which is characterized by high growth factors and leukocytes count. The present study aimed to investigate the effect of advanced platelet-rich fibrin (A-PRF) on the healing of experimentally-induced corneal ulceration in donkeys.
Fifteen apparently healthy adult donkeys of both sexes were selected because they had no ocular abnormalities based on an ophthalmic examination.
After anesthesia and preparation for aseptic surgery, a 6-mm-diameter centric corneal ulceration was induced chemically by using 1N sodium hydroxide solution. The eye was then irrigated with 20 ml physiological saline. The donkeys were then randomly allocated into three main groups; A, B, and C. In group (A) n=3: The corneal ulcer left for the period of the study without application of medicaments. In group (B) n=6: A PRF-gel was applied to the eye once a day at the days 0, 2, 4, 6, 9, 13, 20, 27, and 35 of corneal ulcer induction. In group (C) n=6: In this group, 4 drops of s-PRF in a form of eye drops were installed topically 3 times daily (q 8 h) during the study period from day 0 to 35.
All animals were kept under complete observation after induction of ulcer. The condition of the corneal ulcer was recorded at days 2, 4, 6, 9, 13, 20, 27, and 35 after induction of the ulcer to record the changes in the healing of the corneal ulcers. Evaluation criteria were clinical and external ophthalmic examinations, fluorescein staining, ulcer healing and histopathology. The data were expressed as the mean ± SE and were analysed statistically.
Results revealed that all animals returned to their normal activity and food intake by day five. The Physiological parameters (HR, RR, and BT) were within normal range and there were no significant difference between physiological values before induction of the ulcers and after induction.
Ophthalmic signs including blepharospasm, epiphora, corneal opacity, corneal vascularization either superficial or deep, and conjunctivitis were variably noticed in all groups. Results of fluorescein staining test was variable. Some complications were recorded during this study including; pigmentary keratitis (group A), anterior synechia and pigmentary keratitis (group B), and anterior synechia, iris prolapse and pigmentary keratitis (group C).
Surface area (cm2) of the ulcer which was measured by ImageJ software revealed significant decreases over time in all groups. Significant differences between groups were noticed at day 20 after induction of ulceration.
Histopathological examination revealed variation in the architecture pattern of the healed cornea between groups with the cornea treated with A-PRF gel being superior.
In conclusion, advanced platelet-rich fibrin played a role in corneal ulcer healing with gel form being superior to drops. Histological results of the PRF-gel group were better than other groups. However, corneal ulcer healing was associated with fewer complications compared to control group.