The Effects of Alcohol Intoxication and Burn Injury on the Expression of Claudins and Mucins in the Small and Large Intestines

Abstract

Alcohol intoxication at the time of burn injury exacerbates post-burn pathogenesis. Recent findings suggest gut barrier integrity is compromised after combined alcohol and burn insult, which could contribute to these complications. Tight junction proteins and mucins play critical roles in keeping the gut barrier intact. Therefore, the goal of this study was to examine the effects of alcohol and burn injury on claudin and mucin expression in the intestines. We also evaluated if the combined insult differentially influences their expression in the small and large intestines. Male C57BL/6 mice were given a single dose of 2.9g/kg ethanol prior to a ~12.5% body area burn. One and three days following injury, we profiled expression of several tight junction proteins, mucin, and bacterial 16S rRNA genes in small and large intestine using qPCR. We observed >50% decrease in claudin-4 and claudin-8 genes in both ileal and colonic epithelial cells one day after injury. Claudin-2 was significantly upregulated, and occludin was down-regulated in small intestine one day following injury. Mucin-3 expression was substantially elevated (>50%) in small intestine, whereas mucin-2, and mucin-4 were considerably diminished in the colon (>50%) one day following injury. Most parameters were normalized to sham levels on day three, except for mucin-3 and claudin-8, which remained decreased in large intestine. Neither alcohol nor burn alone resulted in changes in junction or mucin gene expression compared to shams. This was accompanied with increases in the family of Gram-negative bacteria, Enterobacteriaceae, in both small and large intestine one day following injury. These findings suggest that alcohol and burn injury disrupts normal gut microbiota and alters tight junction and mucin expression in the small and large intestines.

Interleukin-22 Prevents Microbial Dysbiosis and Promotes Intestinal Barrier Regeneration Following Acute Injury

“…Previous data from our laboratory has demonstrated that there is a significant increase in both total bacteria and Enterobacteriaceae in the small intestine luminal content following the combined ethanol and burn injury (18). Therefore, we sought to quantify the ability of small intestine epithelial cells to produce anti-microbial peptides following the combined injury.…”

Rhubarb extract prevents hepatic inflammation induced by acute alcohol intake, an effect related to the modulation of the gut microbiota

“…In accordance with these observations, data suggest that blocking signaling and pro-oxidant producing enzymes in rodents via genetic alterations also protect against steatosis, without altering ethanol metabolism [9]. Among the other factors, data suggests that the gut microbiota is a potential important target and an actor involved in the gut barrier alteration upon alcohol drinking [10,11]. In humans, our recent results suggest that the gut microbiota is an actor in the gut barrier and in behavioral disorders induced upon alcohol dependence [12].…”

Dysregulation of microRNA biogenesis in the small intestine after ethanol and burn injury

“…The target genes Ct cycle values were normalized to GAPDH Ct values. Data were calculated using the ΔΔCT method and expressed relative to the average of sham vehicle group (6). …”

“…Approximately, 50% of these injuries occur under the influence of alcohol (ethanol) (2–6). Studies have shown that ethanol exposure at the time of burn injury further confounds the post-burn pathogenesis by delaying wound healing, resulting in longer hospitalization, and increasing susceptibility to infections(4, 7, 8).…”