Simultaneous administration of diethylphthalate and ethyl alcohol and its toxicity in male Sprague-Dawley rats

Phthalate esters have been implicated as xenoestrogens. One among them is di-ethylphthalate (DEP), which is used as plasticizer, detergent base, and binder in incense sticks and after-shave lotions. DEP is one of the contaminants of freshwater and marine ecosystems. Incense stick workers are occupationally exposed to DEP and some workers are chronic alcoholics. Therefore, a study was undertaken to evaluate the interactive toxicity of DEP with ethyl alcohol (EtOH) in young male Sprague-Dawley rats. The rats were given 50 ppm DEP (w/v), 5% EtOH (v/v) and a combined dose of 50 ppm DEP (w/v)+EtOH (5% v/v) in water ad libitum for a period of 120 days and were maintained on normal diet. Control animals received normal diet and plain water. During the treatment rats were weighed every week and water consumption per day was measured. After the completion of treatment, liver weight/body weight, liver weight, body weight, serum enzymes and other biochemical parameters were assessed. It was found that there was no significant change observed in body weight, liver weight, liver weight/body weight and water consumption. It was observed that there was a significant decrease in liver aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels in EtOH, DEP and EtOH+DEP treated rats in the order of EtOH>DEP>EtOH+DEP as compared with control. Serum AST, ALT, acid phosphatase (ACP), alkaline phosphatase (ALP), succinate dehydrogenase (SDH) and liver ACP showed significant increase in DEP and EtOH+DEP treated rats in the order of DEP>EtOH+DEP as compared with control and EtOH treated rats. On the contrary, there was no significant change in liver ALP levels in treated rats. There was significant increase in liver SDH, glycogen, total triglyceride, total cholesterol and lipid peroxidation in DEP and EtOH+DEP treated rats, but no significant changes in the serum SDH, glucose and total triglyceride levels. Serum total cholesterol levels in DEP and EtOH+DEP treated rats were significantly high as compared to control and EtOH treated rats. These results show that there is no interaction of DEP with EtOH but DEP alone leads to severe impairment of lipid metabolism coupled with toxic injury to the liver as evident from significantly altered lipid and enzyme levels in the liver and serum. Long term simultaneous exposure to DEP and EtOH may have severe implications for humans who are occupationally exposed to these two xenobiotics.