Jornal de Patologia Clínica e Experimental

Abstrato

Effects of Hyperoxia Exposure on Free Radicals Accumulation in Relation to Ultrastructural Pathological Changes of Diaphragm

Khaldoon Aljerian and Al-Said Haffor

COPD are associated with an increased load on the diaphragm leading to accumulation of reactive oxygen species (ROS) and the subsequent cellular damages and death. The pathological alterations inducted by ROS in the diaphragm during oxygen breathing are not known. The purpose of the present study was to examine the effects of hyperoxia exposure (HP) on free radicals (FR) accumulation in relation to the ultrastructural pathological alterations in the diaphragm. Twenty adult male rats were randomly assigned to two groups; control (C); and hyperoxia (HP). Animals of the HP were breathing 100% O₂ for 72 hr continuously. Both serum and diaphragm tissue supernatant analysis showed significantly higher (p<0.05) FR in HP group, as compared with control group. Ultrastructure examinations showed that HP resulted in variety of pathological alterations in the mitochondria and endoplasmic reticulum that were associated with disarrangement of myofibrils, loss of I-banding for myosin, focal myolysis of the myofilaments, complete fragmentation of myosin, tearing of myofilamments from Z plates and tearing of the endothelial cell of the interstitial blood capillaries. Based on the results of the present study, it can be concluded that hyperoxia-induced acceleration ROS formation damaged the contractile apparatuses of the diaphragm and related endomembrane proteins that could involve intracellular calcium channels proteins.