Effects of Moderate Ethanol Consumption on Expression of Genes Related to Colonic Cell Growth in Young Adult and Older Rats

Abstract

Our previous research showed that moderate ethanol consumption reduced colonic cell proliferation regardless of age. To examine the underlying mechanism, this study examined gene expression related to colonic cell growth. Twenty‐four nondeprived young adult (109 days old) Wistar rats and twenty‐four nondeprived middle‐aged (420 days old) Wistar rats were randomly assigned to an ethanol‐exposed or a non ethanol‐exposed (water control) group (n = 12 per group). The ethanol group was provided voluntary access to a 20% v/v ethanol solution on alternate days for 13 weeks (45 ethanol drinking sessions total), a paradigm which results in mean blood alcohol levels of ~30–50 mg/dl (0.03–0.05 mg%) in the outbred Wistar strain when measured 30–120 min into a standard drinking session. The control group was provided with standard drinking water during the same period. Gene expression of cyclin D1, cyclin dependent kinase 2 (CDK2), cyclin dependent kinase 4 (CDK4), p21, E‐cadherin and p53 were determined by real time polymerase chain reaction in colonic scraped mucosa. CDK2 was downregulated in ethanol‐fed rats compared to the control group (P = 0.017). Cyclin D1 trended toward lower expression (P = 0.095), and p21 trended toward higher expression (P = 0.095) in ethanol‐fed rats compared to controls, with no observed effect of age for either gene. Older rats showed significant decreases in CDK4 (P = 0.001), E cadherin (P = 0.013), and p53 (P = 0.005), with no observed effect of ethanol exposure. These results indicate that moderate ethanol consumption may improve expression of some genes related to important parameters of colonic cell growth and tumorigenesis. Support or Funding Information NIH AA023291