A thermolyzed diet increases oxidative stress, plasma alpha-aldehydes and colonic inflammation in the rat

A thermolyzed diet has the potential of providing exogenous oxidative stress in the form of advanced glycation end-products (AGE) and decreased thiamin. There is then a possibility that it could result in intracellular exposure to alpha-oxoaldehydes (glyoxal and methylglyoxal (MG)) with metabolic and genetic consequences. Two groups of Fischer 344 rats were fed the following diets: group A was given an AIN93G diet (control diet), while group B was given a thermolyzed AIN93G diet for 77 days. At the end of 77 days TK activity in red blood cells; glyoxal/MG levels in the plasma; glyoxal/MG HI protein adducts and dicarbonyls in the plasma, liver and colon tissues; glutathione levels of whole blood; and oxidative stress/inflammatory markers in the colon were measured. The thermolyzed diet resulted in: decreased thiamin status, increased plasma levels of glyoxal/MG and their adducts, increased protein dicarbonyls in the liver and plasma, lowered blood glutathione levels, increased infiltration of macrophages and increased colon nitrotyrosine levels. The thermolyzed diet increased the body burden of AGEs and decreased the thiamin status of the rats. This increased endogenous alpha-oxoaldehydes and oxidative stress has the potential to injure tissues that have low levels of antioxidant defenses such as the colon.