Activation of the NF- κ B and MAPK Signaling Pathways Contributes to the Inflammatory Responses, but Not Cell Injury, in IPEC-1 Cells Challenged with Hydrogen Peroxide.

Oxidative stress can lead to intestinal cell injury as well as the induction of inflammation. It is not clear whether inflammation is an important factor leading to cell injury caused by oxidative stress. The purpose of this study was to investigate the role of inflammation in intestinal injury caused by hydrogen peroxide (H2O2). Our results revealed that H2O2 stimulation significantly decreased the viability of intestinal porcine epithelial cells (IPEC-1), increased lactate dehydrogenase (LDH) activity, and disrupted the distribution of the tight junction protein claudin-1. H2O2 significantly increased the mRNA expression of interleukin-6 (IL-6), IL-8, and tumor necrosis factor-alpha (TNF-alpha). H2O2 stimulation also led to increased phosphorylation of p38 and jun N-terminal kinase (JNK), and p65 NF-kappa B protein translocation into the nucleus of IPEC-1 cells. Cells treated with the NF-kappa B inhibitor (BAY11-7082), the p38 inhibitor (SB202190), or the JNK inhibitor (PD98059) significantly decreased mRNA and protein expression of IL-6, IL-8, and TNF-alpha. However, treatment with mitogen-activated protein kinase (MAPK) or NF-kappa B inhibitors did not prevent the damage effect on cell viability, LDH activity, or the distribution of claudin-1 in cells challenged with H2O2. In summary, our data demonstrate that activation of the NF-kappa B and MAPK signaling pathways can contribute to the inflammatory response, but not cell injury, in IPEC-1 cells challenged with H2O2.