**5. Oats supplementation is an antioxidant**

Oats, like many other plant materials, contain numerous constituents vitamins, minerals, essential fatty acids, -glucan (fermentable fibers), and phytochemicals, including several phenolic compounds. These constituents have been found to possess many types of bioactivity, including antioxidant, antiproliferaton, anti-inflammatory, and detoxification effects, which may contribute to the promotion of good health (Chen et al., 2007).

We hypothesized that oats supplementation protects through its effects on oxidative pathways. We had two primary rationales for our hypothesis. First, it has been generally accepted that oats are of benefit to human health and normal gut growth and function not only because of their nutrient and fiber values, but also, because of their antioxidant and anti-inflammatory activities. Second, several studies have demonstrated the importance of oxidative stress and upregulated iNOS in alcohol-induced tissue injury and organ dysfunction. More specifically, several reports demonstrated the pivotal role of the upregulation of iNOS and oxidative stress in alcohol-induced gut leakiness. For example, our in vitro studies showed that preventing the upregulation of iNOS that is induced by alcohol, using both iNOS inhibitors and dominant negative mutant for iNOS, prevented alcohol-induced disruption of the barrier integrity of intestinal cell monolayers.

Furthermore, we recently showed that inhibition of iNOS by L-NIL reduces EtOH-induced NO overproduction, oxidative tissue injury and gut leakiness in alcohol-treated rats. Our current study, which uses immunohistochemical staining, provides direct evidence that EtOH induces iNOS activation in colonic epithelium and that oats prevent this effect and prevent alcohol-induced intestinal mucosal oxidative stress.

We confirmed our in vitro findings in an animal model of alcoholic steatohepatitis (ASH). We showed that chronic, daily alcohol administration to rats caused gut leakiness. More importantly, we showed that EtOH-induced gut leakiness in rats was associated with

Using miRNA as Biomarkers to Evaluate the Alcohol-Induced Oxidative Stress 325

logarithmic scale (Fig.3), represented by a dot. X-axis: Hy3 signal intensity, y-axis: Hy5 signal intensity. Dashed diagonal lines define the areas of x-fold differential signal intensities. Approximately 30 miRNAs including miR-212, miR-7, miR-145, and miR-146a

are expressed primarily in digestive tract tissues.

Fig. 2. Hy5/Hy3 false-color image after scanning of microarray

The successful development of effective antioxidant therapies remains a key goal, the attainment of which is required to elucidate the role played by accumulation of oxidized molecules in clinical picture of disease associated with oxidative stress. The use of miRNA as a biomarker provides a logical scientific basis for major intervention trials of antioxidants;

such trials could in turn eventually validate or disprove the biomarker concept.

endotoxemia and alcoholic steatohepatitis. Furthermore, we showed that oats supplementation prevents loss of intestinal barrier integrity, endotoxemia and steatohepatitis(Keshavarzian et al., 2001; Tang et al., 2009a). However, the mechanism for the protective effects of oats is unclear.
