Chronic alcohol ingestion enhances tumor necrosis factor-alpha expression and salivary gland apoptosis

We investigated the extent of induction in sublingual salivary gland cells apoptosis and tumor necrosis factor-alpha (TNF-alpha) expression with chronic ethanol ingestion. The experiments were conducted on rats pair-fed for 8 weeks with alcohol-containing and control liquid diet. The animals were killed, their sublingual glands dissected, and the glandular tissue used for quantization of TNF-alpha expression and the assays of acinar cells apoptosis employing sandwich enzyme immunoassay for histone-associated DNA fragments. The mean value for TNF-alpha in sublingual gland of the control group was 22.3 pg/mg of protein and showed a 1.6-fold increase in the chronic ethanol diet group to 36.5 pg/mg of protein. In comparison with the controls, the sublingual gland of the chronic ethanol diet group also exhibited a 3.4-fold enhancement in acinar cell apoptosis. These findings suggest that chronic ethanol ingestion causes the enhancement in TNF-alpha expression and leads to the induction in salivary gland acinar cells apoptosis. Thus, the diminished secretion of saliva in alcoholics may be a direct result of increased salivary gland apoptosis.