Expressão de metaloproteinases de matriz e PCNA em úlceras de córnea profundas, induzidas em coelhos, tratadas com plasma rico em plaquetas

Effects of platelet-rich plasma on corneal re-epithelization and metalloproteinase expression in the cornea of sheep with experimentally-induced infectious keratoconjunctivitis

Background and Aim

Infectious bovine keratoconjunctivitis is the most crucial ophthalmic disease among ruminants worldwide. Moraxella is the bacteria generally associated with this disease and leads to keratitis, conjunctivitis, corneal ulcers, or blindness. Platelet-rich plasma (PRP) effects in corneal ulcers and different ocular superficial diseases in animals and humans are beneficial and enhance rapid healing and improvement, but the effects in infectious keratoconjunctivitis in ruminants are uncertain. This study aimed to examine the effect of PRP on re-epithelization, corneal tissue, clinical signs, and matrix metalloproteinase (MMP) expression in sheep with infectious keratoconjunctivitis.

Materials and Methods

Eighteen sheep were divided into three groups and subjected to a disease-induction experiment. Group 1 (G1) was administered 1.0 mL PRP subconjunctivally, Group 2 (G2) was administered 1.0 mL PRP subconjunctivally and 50 μL gentamicin drops, and the control group (CG) was administered 50 μL saline solution topically every 12 h. Clinical ophthalmologic examination, fluorescein staining, and photography were carried out. Ulcerated areas were measured employing J-Image software. Five and eleven days following the procedure, half of the animals from each group were euthanized, and their corneas were evaluated by histopathology and zymography.

Results

Control Group and G2 epithelialized more rapidly. The CG exhibited fewer clinical signs of ocular disease. In histopathological analysis, in G2, alterations were observed only in the epithelium. The CG and G1 exhibited alterations in the epithelium, stroma, and Descemet's membrane. In zymography, a decline in MMP-2 expression in the animals treated with PRP was detected. Matrix metalloproteinase-9 was significantly expressed in the animals treated with PRP monotherapy, whereas PRP + gentamicin and CG caused a decrease.

Conclusion

Platelet-rich plasma alone did not demonstrate any beneficial effect on re-epithelialization, a decline in clinical signs, tissue alterations, and expression of metalloproteinases. Platelet-rich plasma combined with gentamicin was capable of suppressing MMPs, primarily MMP-9, but do not display positive effects in re-epithelization, reduction of clinical signs, or tissue effects. These outcomes are similar to those discovered in untreated animals, so the use of PRP in patients with infectious keratoconjunctivitis does not offer greater benefits in sheep. Additional research is required to validate the results of PRP use in natural disease presentation.

Allogenic platelet-rich plasma in induced ulcers in rat’s cornea

ABSTRACT The objective in this study was to evaluate the clinic effect of applying allogenic platelet-rich plasma (PRP) heated or not, for treating cornea ulcers, including the dosage of PDGF-BB in the cornea. The ulcers were induced, standardizing the left eye from 81 rats (Ratus norvegicus, albinus variety), assigned randomly into three groups (N=27): control group (CG) which did not receive any topic treatment; heated PRP group (GA) and PRP group (GP), which received topical treatment every eight hours for five days. Each group underwent evaluation at 24 hours (M1), three days (M3) and five days (M5). The clinical exam evaluated the opacity, vascularization and corneal repair. The corneal PDGF-BB was dosed through the ELISA method. The corneal opacity was decreased in PRP-treated animals (GA and GP) and corneal repair time reduced when compared to CG at M1 and M5. Furthermore, GP showed greater vascularization at M3 compared to M1. Applied allogenic PRP eye drops, heated or not, speed up corneal healing, and reduce corneal repair time. However, the corneal PDGF concentration was not altered in any of the treatments.