Supplementation of N-Acetylcysteine Normalizes Lipopolysaccharide-Induced Nuclear Factor κB Activation and Proinflammatory Cytokine Production During Early Rehabilitation of Protein Malnourished Mice

Increased sensitivity to septic shock has been reported in protein malnourished patients. In this study, we used an animal septic shock model to investigate effects of glutathione (GSH) levels on nuclear factor κB (NFκB) activation and proinflammatory cytokine production in protein malnutrition. We further investigated molecular mechanisms by which protein malnutrition influenced inflammatory responses. CD-1 mice were fed for 3 wk a normal protein (150 g/kg) diet or a protein-deficient (5 g/kg) diet, or for 2 wk a protein-deficient diet followed by 1 wk of N-acetylcysteine (NAC) supplementation. Lipopolysaccharide (LPS) was injected intravenously, and liver was collected at 0, 15 min, 1, 4, 24 and 48 h after LPS administration. Protein malnutrition significantly increased the activation of NFκB and transcription levels of its downstream genes interleukin-1β and tumor necrosis factor-α. Peak NFκB activation was inversely associated with GSH levels (r = −0.939, P < 0.0001) but positively correlated with the GSH disulfide/2GSH reduction potential (r = 0.944 P < 0.0001). We noted unusual NFκB p50/p50 homodimer translocation that was significantly elevated in tissue from protein malnourished mice, along with decreased peak levels of normal p65/p50 heterodimer translocation. Interestingly, mRNA levels of IκB-α were not affected by protein malnutrition. However, early supplementation of NAC to protein malnourished mice without replenishing with dietary protein restored GSH levels and reduction potential, and normalized NFκB activation and proinflammatory cytokine production. Taken together, these findings provide evidence supporting the role of GSH in NFκB activation and inflammatory response in protein malnutrition, and the use of NAC in early rehabilitation of protein malnutrition without a high protein diet.