The effect of systemic application of propolis on tongue damage and oral mucositis in rats exposed to radiation.

Abstract

In this experimental study, the effect of dose-dense systemic application of propolis on oral mucosity, histological changes in papilla, and inflammatory and hypoxic markers in rats exposed to radiation was investigated. Seven rats were in the control and 30 rats in the experimental group. Three experimental groups were formed. In Group 1 RT (15Gy) was delivered only to the head and neck region. In Group 2, RT (15Gy) and systemic administration of 100mg/kg/ml propolis, in Group 3, RT (15Gy) and systemic administration of 200mg/kg/ml propolis were applied. Oral mucositis index (OMI) was scored in control and experimental groups. Proinflammatory markers [interleukin-6 (IL-6), myeloperoxidase (MPO), tumor-necrosis factor-α (TNF-α)] hypoxia markers [glucose transporter-1 (GLUT-1), hypoxia-inducible factor 1α (HIF-1α)] were studied histomorphologically. The significantly highest OMI score was observed in the G1. OMI score was statistically significantly decreased in experimental groups receiving systemic propolis, especially in G3. Proinflammatory markers increased significantly only in the experimental RT group, G1. Serum levels of MPO and TNF-α significantly decreased in the dose-dense systemic propolis arm. The highest levels of hypoxia markers (HIF-1α and GLUT-1) were detected in the RT group, then in G2, G3, and control groups in order of decreasing frequency. However, the difference between the groups did not reach the level of statistical significance. Systemic propolis can be reduced acute mucositis with its anti-inflammatory effect without developing resistance to RT (tumor protection). However, greater number of clinical studies should be designed to arrive at definitive conclusions.