[Study on mercury accumulation in rats induced by badu shengji san]

To study the mercury accumulation in injured skin rats induced by Badu Shengji San (BDSJS), a traditional Chinese medicine preparation for external use.

Injured skin rats were treated with BDSJS for consecutively 4 weeks. During the 4 weeks and the following 4 weeks after the drug withdrawal, samples were collected for determining mercury contents in blood, urine and kidney, with urinary N-acetyl-beta-D-glucosaminidase(NAG) and beta2-microglobulin (beta2-MG) as indicators of renal toxicity and serum biochemical indicators of hepatic and renal functions. Additionally, activated partial thromboplastin time (APTT), prothrombin time (PT) and kidney and renal pathological changes were also observed.

Compared to injured skin rats, mercury contents of blood, urine and kidney were increased significantly in low, middle and high-dose BDSJS groups administered for consecutive 4 weeks. The levels of mercury showed decreases in urine (89%, 78%, 93%) and kidney (55%, 51%, 57%), and blood mercury concentration recovered to the normal range in low, middle and high-dose BDSJS groups after the drug withdrawal for 4 weeks. Kidney coefficient and beta2-MG were remarkably increased and renal tubular epithelial cell swelling could be found in the high-dose group, and kidney coefficient, beta2-MG and renal morphology basically recovered to the normal levels after the drug withdrawal for 4 weeks.

The administration of BDSJS for consecutively 4 weeks can cause mercury accumulation in blood and mainly in kidney. Once the accumulated mercury concentration of kidney reaches a certain level, renal tubular epithelial cells would be injured. 1.1 mg x cm(-2) of BDSJS is proved to be safe and 2.2 mg x cm(-2) can cause mild but reversible injury in the function of kidney which can be recovered after drug withdrawal for 4 weeks.