EVALUATION OF POTENT RADIOPROTECTIVE EFFECT OF DIMETHYL SULFOXIDE FOR ACUTE RADIATION-INDUCED LUNG INJURY: TC99M-DTPA TRANSALVEOLAR CLEARANCE SCINTIGRAPHY CORRELATED BY HISTOPATHOLOGIC FINDINGS

Abstract

This study aims to investigate the radioprotective effects of dimethyl sulfoxide in the acute phase of radiation-induced lung injury by technetium-99m-diethylenetriaminepentaacetic acid transalveolar clearance scintigraphy in a rabbit model. Twenty white New Zealand rabbits were grouped as (1) control, (2) sham irradiation, (3) irradiation plus dimethyl sulfoxide, and (4) dimethyl sulfoxide alone. Right hemithorax regions of the rabbits in the sham irradiation and irradiation plus dimethyl sulfoxide groups were irradiated with a single dose of 20 Gy by a Cobalt60 treatment unit. Dimethyl sulfoxide (4.5 gr/kg) was administered intraperitoneally, 30 minutes before irradiation. The technetium-99m-diethylenetriaminepentaacetic acid transalveolar clearance scintigraphy was performed on the 14th day after irradiation. The rabbits were sacrificed on the 15th day, and both lungs were removed for histopathologic evaluation. Administration of dimethyl sulfoxide before irradiation caused a marked prolongation in the transalveolar clearance rate of diethylenetriaminepentaacetic acid through the alveolocapillary membrane (p=0.028), protected the anatomic ultrastructure of the lung parenchyma, markedly decreased the severity of exudate in the alveoli (p=0.042) in histopathologic evaluation. Our study results showed that dimethyl sulfoxide has safely eliminated inflammatory response induced by irradiation while not causing any negative alterations in the structure of the normal lung tissue and preserving the integrity of the alveolocapillary membrane, especially in the acute phase. Dimethyl sulfoxide appears to be a safe and well-tolerated protective agent for the prevention of RILI. Technetium-99m-diethylenetriaminepentaacetic acid transalveolar clearance scintigraphy is accepted as a cheap, easily reproducible, sensitive assay to monitor radiation toxicity reactions in acute RILI.