Figure 7: Photomicrographs showing histopathological changes in lung tissue: a: Control Lung: Low power photomicrograph of section of lung from control group showing normal lung parenchyma. (HE x 100); b: Low power photomicrograph of section of lung from animal exposed to hypoxia for 2 hour showing normal lung parenchyma. BL = Bronchial Lumen, AS = Alveolar Space. (HE x 100). c: Low power photomicrograph of section of lung from animal exposed to hypoxia for 4 hour showing only mild thickening of alveolar spaces with marginal reduction in alveolar space area, mild thickened inter-alveolar septae. Alveolar spaces are almost normal in size (HE x 100) d: Low power photomicrograph of section of lung from animal exposed to hypoxia for 8 hour showing thickening of alveolar spaces with moderate reduction in alveolar space area, moderately thickened inter-alveolar septae and smaller alveolar spaces (HE x 100); e: Low power photomicrograph of section of lung from animal exposed to hypoxia for 16 hour showing thickening of alveolar spaces with moderate reduction in alveolar space area (Some of the alveolar spaces show traces of edema fluid), moderately thickened inter-alveolar septae (HE x 100); f: Low power photomicrograph of section of lung from animal exposed to hypoxia for 24 hour showing widespread changes of pulmonary edema alveolar spaces filled with pale eosinophilic edema fluid, the inter-alveolar septae are mildly thickened (HE x 100); g: Low power photomicrograph of section of lung from animal exposed to hypoxia for 48 hour showing, pronounced thickening of alveolar spaces with resultant reduction in alveolar space area, and severely thickened inter-alveolar septae (HE x 100).