Avaliação da atividade anti-inflamatória e antioxidante da Olmesartana em modelo experimental de mucosite oral

Abstract

Oral Mucositis (MO) is one of the main complications involved in the treatment of cancer, especially in the head and neck region. It is an inflammation that affects the mucosa of the oral cavity is clinically characterized by erythematous, ulcerated and painful lesions, Which can lead, in more severe cases, to an interruption of chemotherapy treatment. The aim of this study was to evaluate the effect of Olmesartan (Olme), an angiotensin II (Ang II) receptor antagonist, on oral mucositis. A pre-clinical trial was performed, in vivo, randomized, blind, with use of control groups. 42 Golden Siriam hamsters were divided into 6 groups: Control, Mechanical Trauma, 5-FU, Olme 1mg/kg, Olme 5mg/kg and Olme 10mg/kg. In the diseased groups MO was induced on the first two days of the experiment with a chemotherapeutic, 5- fluorouracil (5-FU, 60 mg / kg day 1 and 40 mg / kg day 2). Animals were pretreated with oral Olme (1, 5, or 10 mg/kg) or vehicle (control) 30 min before 5-FU injection and daily until day 10. Cheek pouch samples were subjected to histopathologic analysis, protein/immunology analysis, and immunoistochemistry. Reverse transcriptase polymerase chain reactions (RT-PCRs) were used to quantitate expression of NF- κBp65, PI3K, and MKP1. Inducible nitric oxide synthase (iNOS) and extracellular regulated kinase (ERK)1/2 levels were analysed with immunoblots. Treatment with 10 mg/kg Olme reduced ulceration, myeloperoxidase (MPO) and malonaldehyde (MDA) levels, cellular inflammation, edema, and hemorrhage (p<0.05). The 10 mg/kg Olme treatment also reduced tumour necrosis factor (TNF)-α, interleukin (IL)-1β, increasing expression PI3K, and decreasing expression of NFKBp65, MKP1, and decreasing iNOS and ERK1/2 levels. Olme at a dose of 10 mg/kg prevented the mucosal damage and inflammation associated with 5-FU– induced OM.