Avaliação do potencial cicatrizante do colágeno extraído da pele de tilápia do Nilo em úlceras traumáticas de mucosa jugal em ratos

Abstract

Traumatic ulcers are painful and common lesions of the oral mucosa, with no well-defined therapeutic protocol. Nile tilapia skin appears as a possible alternative treatment, as it shows improvement in the healing of skin wounds in animal and human studies. The objective of this study was to evaluate the healing potential of collagen extracted from Nile tilapia skin (NTSC) in an experimental model of traumatic oral ulcers in rats. The study included 120 male Wistar rats, which were randomly divided into three groups, which were treated topically, twice a day, with: 1% NTSC in orabase (NTSC-Ob), orabase without collagen (Ob) and triamcinolone acetonide in orabase (Triamcinolone-Ob). Traumatic ulcers were induced in the left jugal mucosa using a dermatological punch measuring 8 mm in diameter. Topical administration was performed until the days of euthanasia (days 1, 5, 10, 15 and 20, after ulceration), where the ulcers were clinically measured to calculate the area and percentage of contraction (relation between initial and final area) and the weighed animals to calculate body mass variation. Histological slides were prepared for analysis through scores (presence or absence of epithelium and connective tissue repair) and histomorphometric (polymorphonuclear (PMN), mononuclear (MN), blood vessels (BV) and fibroblasts/myofibroblasts analysis. Picrosirius Red staining was performed for collagen analysis and immunohistochemistry for CD31, α-SMA and TGF-β markers. For the statistical analysis, the GraphPad Prism® 5.0 software was used and the significance index p<0.05 was adopted in all evaluations. On the 15th day, the NTSC-Ob and Triamcinolone-Ob groups showed a smaller ulcer area and a higher percentage of contraction (p=0.0061), total re-epithelialization (p<0.001), best histological repair scores (p=0.012) and a lower number of PMN (p=0.0029) compared to the Ob group. Also on that day, the NTSC-Ob group showed a greater number of BV (p=0.017), greater deposition of total collagen, collagen type I and type III (p<0, 05) and higher expression of CD31, α-SMA and TGF-β (p<0.05) compared to the Ob and Triamcinolone-Ob groups. On the 20th day, the NTSC-Ob group obtained a greater weight gain in relation to the Ob and Triamcinolone-Ob groups (p<0.0001). It is concluded that NTSC in orabase optimizes the healing of traumatic ulcers by stimulating re-epithelialization, angiogenesis and collagenesis, with an important role of TGF-β in this process.