The Evaluation Of The Safety And Lead Accumulation Of Gou-pi Plaster (a Traditional External Preparation)

Objective:To evaluate the the safety of long-term external use of the traditional external preparation Gou-pi plaster and the accumulation behavior of lead in rats, then reveal the potential toxicity, toxic target organs and underlying mechanism of long-term external use of Gou-pi plaster, and provided scientific evidence to the clinical use of Gou-pi plaster.Method:Firstly, the safety of external use of Gou-pi plaster was observed by utilizing the following methods:acute dermal toxicity test, skin irritation test and skin sensitization test.Secondly, Gou-pi plaster was administered externally at dosages of7.0,3.5and1.75g/kg once every other day for a total of90days. Then the possible toxic characteristics of Gou-pi plaster were observed, and then predicted the possible clinical adverse reactions, including the its nature and degree; Furthermore, speculated the toxicity target organs and safe dosage of Gou-pi plaster, and prompted the index which should be greatly concerned in clinical use, as well as provided reference information for the use of Gou-pi plaster.Thirdly, the percutaneous absorption of lead contained in Gou-pi plaster was investigated in vitro skin via microwave digestion/graphite furnace atomic absorption spectrometric method.Fourthly, the blood lead levels were evaluated by flame atomic absorption spectrometric method, then the change regularity of blood lead was investigated in long-term toxicity study of Gou-pi plaster in rats.Fifthly, the accumulation of lead was determined by flame atomic absorption spectrometric method in long-term toxicity study of Gou-pi plaster in rats.Finally, the levels of urinary enzymes and protein, such as B2-microglobulin and N-acetyl-β-D-glucosaminidase, were used to be evaluated the renal function of rats in long-term toxicity study of Gou-pi plaster. Results:Firstly, Gou-pi plaster did not cause skin acute toxicity, irritation and sensitization, which indicated that Gou-pi plaster possessed a higher external use safety.Secondly, the general conditions of all animals had not abnormal changes in chronic toxicity study, including body weight, food intake, mentality, physique, activity, clothing hair, local treated skin, mucosal, and secretions. Hematological and biochemical results indicated that Gou-pi plaster could decrease the levels of leukocyte, platelet, mean platelet volume, mean platelet distribution width, and creatinine, increase the level of alkaline phosphatase. However, the changes of these parameters were within the fluctuation of normal physiological value. Furthermore, Gou-pi plaster could increase the kidney-body weight index. Moreover, no other significant differences were observed among the groups.Thirdly, the study suggested that the lead contained in the Gou-pi plaster through the skin in zero-level release equation so as the prompt that the amount of the lead the permeating through the skin is increasing time goes on when the Gou-pi plaster is being used.Fourthly, the linear relationship, accuracy, and reproducibility of flame atomic absorption spectrometric method were conformed the requirements, and which could be used to determine the blood lead level. After treatment of Gou-pi plaster, the blood lead level of rats significantly increased, and maintained in a higher level in the recovery period.Fifthly, during the administration and recovery period, the elevated lead accumulations in kidney, liver and brain were observed in Gou-pi plaster treated rats. However, the elevated lead accumulation in heart was only observed after45days of treatment.Finally, high dosages of Gou-pi plaster and matrix could increase the levels of N-acetyl-B-D-glucosaminidase after90days of treatment and recovery period. And the levels of B2-microglobulin had no obvious changes. Conclusion:External use of Gou-pi plaster did not cause obvious skin acute toxicity, irritation and sensitization. After90days of external use of Gou-pi plaster (7.0g/kg), there were no significant changes of the general body parameters, hematological parameters, biochemical parameters, bone marrow parameters, and histopathological parameters. However, Gou-pi plaster could increase the kidney-body weight index, which indicated that treatment of Gou-pi plaster might have effect on the renal function. Furthermore, the results obtained from absorption test, we found that the lead contained in the Gou-pi plaster through the skin in zero-level release equation so as the prompt that the amount of the lead the permeating through the skin is increasing time goes on when the Gou-pi plaster is being used. Therefore, the lead contained in Gou-pi plaster could be absorbed via skin, and then caused the elevated level of blood lead. Subsequently, the lead would be accumulated in some important organs, especially in kidney, which would cause renal tubular dysfunction. Furthermore, a clinical study indicated that the lead levels in blood and urine were elevated after treatment of Gou-pi plaster for three weeks, but the lead levels were lower than its poisoning limit. In summary, the toxicity target organ of Gou-pi plaster might be kidney, and long-term use of Gou-pi plaster would cause early renal tubular injury. Hence, the use of time and dosage of Gou-pi plaster should be controlled in the clinical usage of Gou-pi plaster; Furthermore, the early indicators of renal injury also should be greatly and closely concerned.