European Journal of Biomedical and Pharmaceutical Sciences

VISUAL AND HISTOPATHOLOGICAL CHANGES OF RAT LUNGS FOLLOWING INHALATION OF A LETHAL DOSE OF PHOSGENE

Hussain Al–Wandawi* and Ibrahim A. Hassan

ABSTRACT

Background: Phosgene, CAS 75 – 44 – 5, is a highly toxic gas at ambient temperature and pressure. It is widely used in manufacture of plastics, dyes, pharmaceuticals and pesticides. It can also be generated in advertently during fire involving plastic and other chemicals and solvents containing chlorine. Inhalation is the main route of exposure. Besides occupational exposure, phosgene is also of concern to emergency teams including early responders. Lethal dose of phosgene in humans is approximately 500 ppm / min of exposure or exposure to 3 ppm for 170 minis equally as fatal as exposure at 30 ppm for 17min.Exposure through inhalation to 3 – 4 ppm can produce an immediate irritant reaction that typically lasts 3 – 30 minutes and includes lacrimation, conjunctiva irritation, burning sensation in mouth and throat. Inhalation of high concentrations of phosgene may cause initially symptoms of respiratory tract irritation, patients may feel temporarily fine but a day later may manifests difficulty or shortness of breath, nausea and vomiting, and chocking may develop within 2 – 6. Skin contact can result in lesions similar to those of burns and frost. Methodology: Liquid phosgene (69.6 mg) was injected into a 20 liter static exposure chamber (Fig.1) to obtain phosgene concentration of 3.48 mg / liter. Based on conversion factor and calculation method reported in literature (CHSR, 2006) this was found to account to 868 ppm. This was checked by Gas Chromatography according to the method reported by (OSHA,1980). Animals: Male albino rats (Ratus ratus) weighing 170 – 250 g, whole body exposed to a single lethal concentration of phosgene gas at 868 ppm for 2 min. The exposure chamber was then immediately recondition for 30 min, the animals were then individually re-caged and kept under pre- exposure conditions. The animals were then sacrificed at different time intervals within the observation period (2 – 8 h). The animals within the control group were treated similar way but without exposure to phosgene gas. The lungs of all exposed and non - exposed animals were subjected to visual and histopathological examinations. Lung section for histopathological studies were prepared following the method described by Baker and Silverton (1976). The statistical analysis was carried out using one – way classification analysis of unequal variance test (Duncan, 1955).

Keywords: Rats, whole body, phosgene exposure, visual and histopathological changes lungs.