Effect of Ambient Temperature Changes on Lung Tissue Injury in Rats

Objective To investigate the lung tissue injury in rats following ambient temperature changes.Methods Eighty-four male SD rats aged 9-15 weeks were randomized into four groups: normal temperature(20 ℃ group),sudden rise in temperature to 37 ℃(37 ℃ group),sudden drop in temperature to 4 ℃(4 ℃ group) and sudden drop in temperature to-12 ℃(-12 ℃ group),with 21 rats in each group.Three rats in each group were observed at 1,4,8,12,24,48 and 168 hours,respectively.Animals were sacrificed at different time points.The upper lobes of the left lung were collected,fixed in 4% paraformaldehyde solution for 24 hours.Paraffin-embedded tissue sections were used for HE staining to observe pulmonary histopathological changes.Results Different degrees of damage was found in lung tissues in rats undergoing ambient temperature changes,especially in group 37 ℃ group.Lesions mainly included capillarectasia,congestion,bleeding,bronchial mucosal epithelial necrosis and inflammatory cell infiltration.The most obvious damage was found at 12 hours in 37 ℃ group,at 24 hours in 4 ℃ group and at 24 hours in-12 ℃ group.Conclusion Ambient temperature changes can cause lung tissue injury,including capillarectasia,congestion,haemorrhagia,bronchial mucosal epithelial necrosis and inflammatory cell infiltration.