Characterization of immune cells in the rat intestinal mucosa and liver involved in inflammation caused by LPS and evaluation of the effects of N-acetylcysteine and disulfiram (well-known sulfur drugs) for this inflammation

Abstract

Lipopolysaccharide (LPS)-induced inflammation is an experimental rat model often used as a tool for testing new drugs as candidates for treating various diseases associated with inflammation. New methods now allow for precise imaging of tissues and changes induced by various factors. To increase knowledge about LPS-induced inflammation and promote strategies for investigating new therapies, this study aims to characterize immune cells involved in inflammation in the rat intestinal mucosa and liver and to evaluate the therapeutic effect of two well-known sulfur drugs N-acetylcysteine (NAC) and disulfiram (DSF) on this model LPS was administered intraperitoneally to rats once a day, for 10 days. NAC and DSF were administered 5 h after LPS. At the end of experiment, animals were euthanized, and the intestine and liver were collected. The immune cells of the intestinal mucosa and liver were characterized with the following antibodies: Toll-like receptors (TLR2 and TLR4), smooth muscle alpha-actin (α-SMA), major histocompatibility complex II (MHC-II), and serotonin (5-HT). In samples obtained from inflamed rat intestinal mucosa, it was possible to detect TLR2-positive and TLR4-positive cells, and numerous α-SMA-positive cells, indicating an inflammatory state. Furthermore, an increase in serotonin positive neuroendocrine cells compared to normal was demonstrated, which could be associated with intestinal inflammation. The number of these positive cells was much smaller in the samples derived from animals treated with NAC or DSF, suggesting anti-inflammatory action of these drugs. In the inflamed rat liver, several immune cells positive for these antibodies were observed and NAC or DSF decreased the amount of these positive cells. In conclusion, this study shows that bacterial LPS can activate various innate immune system cell populations, such as dendritic cells, neutrophils, Kupffer cells, myofibroblasts and enterocytes. Moreover, this study demonstrates the beneficial effects on NAC and DSF in alleviating inflammation and relieving tissue fibrosis in the LPS-induced inflammation in the rat intestinal mucosa and liver.