Evaluation of the effect of methylene blue administered by intradermal way in the necrosis progression in burn injury in rats

• Grant number: 14/24116-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2015
• End date: June 30, 2016
• Field of knowledge: Health Sciences - Medicine - Surgery
• Principal Investigator: Paulo Roberto Barbosa Evora
• Grantee: Vinicius Fernando Machado Beldi
• Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

The burn injury shows central necrosis, and the adjacent area of ischemia may or may not progress to necrosis. The concentration of nitric oxide (NO) increases with burn, and this molecule combines with superoxide anion (O2-) to form peroxynitrite (ONOO-), which is a potent oxidizing agent. Among other effects, methylene blue (MB) acts as an antioxidant and it is supposed to reduce the progression of the burn. Objectives: To evaluate the effects of methylene blue administered by intradermal way in the progression of necrosis in the interspace between the burned areas in a burn model in rats. Materials and methods: A metal comb will be heated in boiling water, and two burn injuries will be performed by applying the metal comb on the back of male Wistar rats (250 g) for 30 seconds, resulting in burn injuries of four rectangular (10 x 20 mm) total thickness separated by three interspaces (5 x 20 mm) of unburned skin (zone of ischemia). The animals will be divided into three groups (n = 8): a control group, a group that will receive MB (2mg / kg) by intradermal way an hour after the injury, and the third group, after six hours. Seven days past, the lesions will be photographed for visual analysis of necrosis in the interspaces. Then total thickness cuts of the lesions will be obtained, stained with Masson's trichrome and evaluated for evidence of necrosis. Tissue fragments of burned areas and unburned interspaces will be obtained separately and processed for tissue dose of nitrite / nitrate (NOx), products of NO degradation and malondialdehyde (MDA), a marker of oxidative stress.