Histamine Prevents Functional and Histological Alterations of Salivary Glands Exerted by Ionizing Radiation.

VANINA A MEDINA; JUAN P PRESTIFILIPPO; MAXIMO CROCI; ROSA M BERGOC; JUAN C ELVERDIN; ELENA S RIVERA

Fulda, Alemania

Congreso; European Histamine Research Society, XXXVIII Annual Meeting.; 2009

European Histamine Research Society,

Xerostomia is a common, disturbing side effect among patients treated with radiotherapy for head-and-neck cancer leading to considerable morbidity. It is associated with severe functional and structural alterations of salivary glands causing secretory hypofunction. The submandibular gland (SMG) is one of the major salivary glands, being the main producer of saliva. We have previously demonstrated that histamine treatment significantly protects small intestine and bone marrow against radiation-induced toxicity. The aim of the present study was to investigate whether histamine could prevent salivary gland dysfunction and histology alteration exerted by ionizing radiation. For that purpose, 30 rats were divided into 4 groups. Histamine and Histamine-10Gy groups received a daily sc histamine injection (0.1 mg/kg) starting 20 hours before irradiation. Histamine-10Gy and untreated-10Gy groups were irradiated with a single dose on whole-body using Cesium-137 source. 3 days post irradiation metacholine induced salivary secretion was measured or animals were sacrificed and SMG removed, fixed, stained with hematoxylin and eosin and histological characteristics were evaluated. We studied by immunohistochemistry the expression of proliferation markers, histidine decarboxylase (HDC) and histamine content. Results indicate that radiation decreased salivary secretion by 40% in comparison to untreated rats, which was associated with a loss of SMG mass and an alteration of epithelial architecture, partial loss of secretor granular material, anisokaryosis and diminished proliferation. In contrast, histamine completely reversed the reduced salivation induced by radiation, significantly conserved glandular mass with normal appearance and preserved structure organization of secretor granules. Histamine and HDC was detected principally in ductal cells. We conclude that histamine prevents radiation-induced damage on SMG being of potential clinical value for patients undergoing radiotherapy.