Effects of p38 mitogen-activated protein kinase on lung ischemia-reperfusion injury in diabetic rats

Lung ischemia-reperfusion injury (LIRI) is a pathologic process that is observed in several clinical conditions, and p38 mitogen-activated protein kinase (MAPK) is involved. Diabetes mellitus (DM) results in an increased incidence of ischemia-induced organ damage. The aims of this study were to examine the effects of DM on LIRI in a rat model of DM and to explore the possible mechanisms in relation to the p38 MAPK pathway.

Forty rats were randomly divided into the following five groups (n = 8 each): a control + sham group, a control + IR group (CIR), a DM + sham group, a DM + IR group (DIR), and a DM + IR + SB203580 group. The control and streptozotocin-induced diabetic rats underwent a sham operation or left hilum occlusion for 90 min followed by reperfusion for 4 h. SB203580 was used to inhibit the p38 MAPK pathway. The pulmonary oxygenation index, inflammatory cytokines in the serum, lung edema, histopathology, oxidant stress, apoptosis, and phosphorylated/total-p38 MAPK protein levels were measured.

The DIR group displayed greater concentrations of tumor necrosis factor-α, interleukin-6, and intercellular adhesion molecule-1 and increases in the wet weight-to-dry weight ratio, lung injury scores, malondialdehyde levels, and cellular apoptosis, and these effects were accompanied by lower pulmonary oxygenation compared with the CIR group (P < 0.05). In the DIR group, the expression levels of p38 MAPK protein were significantly upregulated compared with those of the CIR group. Additionally, all of these alterations were attenuated in the DM + IR + SB203580 group compared with the DIR group.

Diabetes exacerbates LIRI by activating the p38 MAPK pathway.