Significance of the changes occurring in the levels of interleukins, SOD and MDA in rat pulmonary tissue following exposure to different altitudes and exposure times.

The aim of the present study was to investigate the changes occurring in the levels of interleukin, superoxide dismutase (SOD) and malondialdehyde (MDA) in rat lung tissue at different altitudes and times, and to determine the significance of such changes. A total of 88 Wistar rats were randomly divided into 3 groups as follows: the control group [low altitude (LA), 1,500 m; n=8], the moderate altitude group (MA group, 2,260 m; n=40) and the high altitude group (HA group, 5,000 m; n=40). The moderate and high altitude groups were subdivided into the 1, 3, 7, 15 and 30 day groups (MA1, 3, 7, 15, 30 and HA1, 3, 7, 15, 30; n=8). The levels of interleukins (IL-6, IL-8 and IL-10) in the rat lung tissue were determined by ELISA. The WST-1 Cell Proliferation Assay kit and total bile acids assay were used to determine the activity levels of SOD and the content of MDA, respectively. Compared to the control group, the levels of IL-6/IL-8/IL-10 were higher in the MA1 group; however, no significant differences were observed between the other MA subgroups. In addition, no significant differences were detected in SOD activity and the MDA content in the MA subgroups. The levels of IL-6/IL-8 in all the HA subgroups were higher compared to those of the control group, and with the passing of time, the levels of IL-6/IL-8 decreased, but were still higher than those of the control group. However, the level of IL-10 decreased with the passing of time, and was lower in all the HA subgroups compared to the control group. With the passing of time, SOD activity decreased, and the MDA content gradually increased. On the whole, the findings of this study indicate that hypoxia due to high altitude induces lung inflammation and oxidative damage, which subsequently causes severe damage to lung tissue.