Oxidative stress is important in the pathogenesis of stress-related mucosal disease

Stress-related mucosal disease (SRMD) is a common complication in patients in the intensive care unit (ICU). The aim of the present study was to investigate the possible mechanisms for the pathogenesis of SRMD. In total, 38 patients with SRMD were enrolled from an ICU, as well as 15 healthy volunteers. The disease severity of patients in ICU was evaluated using the Acute Physiology and Chronic Health Evaluation (APACHE) II score. Gastric mucosa with the most severe lesions were biopsied for hematoxylin and eosin staining and then assessed by pathological damage scoring. The serum levels of malondialdehyde (MDA), superoxide dismutase (SOD) and ischemic modified albumin (IMA) were also detected. In addition, claudin-3 and inducible nitric oxide (NO) synthase (iNOS) in the gastric mucosa were assessed by western blotting and immunohistochemistry. The average APACHE II score of the patients with SRMD was significantly higher compared with the controls. Moreover, the levels of MDA (4.74±2.89 nmol/ml) and IMA (93.61±10.78 U/ml) in patients with SRMD were significantly higher compared with the controls (P<0.001), while those of SOD (89.66±12.85 U/ml) in the patients with SRMD were significantly lower compared with the controls (P<0.001). Furthermore, compared with the control, iNOS expression was significantly higher (P=0.034), while the expression of claudin-3 was significantly lower in patients with SRMD (P<0.001). The results indicated that APACHE II score was positively correlated with pathological damage score (r=0.639, P<0.001) and levels of MDA (r=0.743, P<0.001), but negatively correlated with the level of SOD (r=-0.392, P=0.015). In addition, MDA was positively correlated with IMA (r=0.380, P=0.018), but negatively correlated with claudin-3 (r=-0.377, P=0.020). Therefore, it was speculated that oxidative stress may play an important role in the pathogenesis of SRMD, and NO levels and cell membrane permeability are altered during this process.