Study of cell activation and cytokines in cutaneous repair in diabetic rats treated with low level laser therapy

Abstract

The healing process of diabetic patients is often inefficient leading to chronic ulcers. Laser therapy is a promising tool to assist the closure of these wounds, but lack of standardization of dosimetry and understanding of their cellular and molecular mechanisms of action limit their use. This study aims to evaluate cell activation and cytokines in wound repair in diabetic animals which underwent laser therapy comparing two systems of delivery of laser light. Will be used 54 male Wistar rats (Rattus norvegicus albinus) with diabetes induced by intraperitoneal injection of streptozotocin (50mg/kg). The ulcer will be made using a 8 mm-punch in the back of the animal after trichotomy. Experimental groups: (1) control group (CG) - the sore back will not be subjected to treatment, (2) single dose (SDG) - dorsal ulcer will receive laser therapy two hours after the wound, (3) fractionated dose (FDG) - the ulcer will receive laser therapy on days 0, 3, 8, 10. Laser parameters for application in SGD will be: » = (660 ± 2) nm, I = 6mW/cm2, D= 4 J/cm2, t = 668 s; and for FDG group will be four doses of » = (660 ± 2) nm, I = 6mW/cm2, D= 1 J/cm2, t = 167 s totalizing 4 J/cm2. At days 0, 3, 8, 10, 14 e 21 the animals will be euthanized and the ulcers will be removed, routinely processed for hematoxylin & eosin stain and for immunohistochemistry to the following antigens: CD3, CD45RO, elastase, CD68, CD31, IL-1, IL-8, MCP-1 and VEGF. It will be assessed the presence and type of the inflammatory infiltrate, presence of granulation tissue, number of lymphocyte T, activated T lymphocytes, neutrophils, macrophages, angiogenic cells, as well as the production of cytokines above mentioned. The data will be assessed for normality and subjected to appropriate statistical analysis. (AU)