Toxicology and Pharmacology

Biography

Biography: Zhi-Zhong Guan

Abstract

Endemic fluorosis widely occurs in the world and is characterized by skeletal and dental fluorosis and a vast array of pathological changes in whole bodies. Coal-burning type of endemic fluorosis is the severest one, which was confirmed in China in 1970’s. This type of endemic fluorosis is primarily induced by fluoride-contamination from food and air indoor due to the emitted smoke during burning coal (containing high amount of fluoride) in opened stoves for drying food in Autumn harvest and warm oneself in Winter by the residents in the areas. In Guizhou Province of China, about 15 million of people live in such areas of coal-burning type of endemic fluorosis. Among the population, 10 millions are suffered from dental fluorosis and 0.8 million skeletal fluorosis. Since 1980, an efficient strategy relating the integrated control has been carried out for eliminating the disease in the areas of China. First, the adapted stoves without pollution from burning coal have been set up, which brings the significant decline of fluoride contamination on food and air indoor; second, education relating the harm of fluoride pollution from coal burning on body to the residents has been carried out. After taking the strategy for many years, the numbers of the patients with dental or skeletal fluorosis has been significantly decreased, indicating that the coal-burning type of endemic fluorosis in China has been efficiently controlled. On the other hand, the basic researches have been carried out to understand the pathological changes and the molecular pathogenesis. The damages of excessive fluoride on multiple organs of the patients besides the skeletal and dental fluorosis have been found. In addition, we suggested earlier that the increased level of free radical resulted from fluoride might the main mechanism in the damages of multiple organs or systems by fluorosis, which has been subsequently confirmed by large number of investigates. In our results, as compared to control cases, the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST) and the expressions of SOD and GST mRNAs as well as the raised malondialdehyde (MDA) level were significantly decreased in the blood of the population living in the areas with severe coal-burning endemic fluorosis. The changes of hepatic and renal functions were detected in the residents living in the areas of endemic fluorosis. Interestingly, the health conditions of the residents in the endemic fluorosis area has been greatly improved after several years of the integrated control. Furthermore, the clinic treatments for the patients with dental and skeletal fluorosis have been performed by the dentists and surgeons, the imaging diagnosis has been improved by the imaging doctors in our hospital, in which the better results have been achieved. The pharmaceutical drugs for the treatment to the patients with chronic fluorosis have also been investigated and the preclinical results have been obtained in our group. Importantly, it is necessary to notice that we should take a long-period of integrated control for efficiently eliminating the hazard of coal-burning type of endemic fluorosis.