DNA Damage in T and B Lymphocytes, Bone Marrow, Spleens, and Livers of Rats Exposed to Benzene

Abstract

Single-cell gel electrophoresis assays were performed in order to evaluate DNA damage occurring in the T and B lymphocytes, spleens, bone marrow, and livers of rats exposed to benzene at a concentration of 100, 200, or 400 ppm for 2 or 4 wk. The level of t,t-muconic acid (t,t-MA), which is a urinary benzene metabolite, was determined. In the control rats, mean Olive tail moments in the T and B lymphocytes were 1.507 ± 0.398 and 1.579 ± 0.206, respectively. DNA damage in the T and B lymphocytes exposed to 400 ppm benzene for 4 wk caused those rats to exhibit the highest Olive tail moments, with their values measured as 4.351 ± 0.510 and 3.140 ± 0.631, respectively. Also, the t,t-MA levels increased directly with increasing benzene exposure time and dose during the 4 wk. After 4 wk, the levels of t,t-MA in urine from rats exposed to 100, 200, and 400 ppm were 19.30 ± 5.62, 30.36 ± 4.46, and 46.93 ± 9.10 mg/g creatinine. In conclusion, the present study demonstrates that benzene exposure results in significant DNA damage in the T and B lymphocytes, bone marrow, spleens, and livers of rats. DNA damage in the blood cells and organs was also discovered to vary directly with benzene exposure, in both a dose-dependent and time-dependent manner. In addition, a similar trend regarding DNA damage was found in the blood cells and organs, and evidenced a good association with the level of t,t-MA in the urine.