Study On Toxicities Of Fluoride In Low Nutrition State To Rat Hard Tissues And DNA And On Nutritional Provisions And Their Mechanisms

Endemic fluorosis is a whole - body chronic poisoning disease by long -term over ingested fluoride with dental fluorosis and skeletal fluorosis as its two main symptoms. The patients with skeletal fluorosis may be crippled in its severe stage. The disease is the most serious endemic disease with the widest distribution in the world. Malnutrition and Lack of calcium in foods may be the trigger factors of the disease. The aims of the animal experimental study were to create a drinking-water-type chronic fluorosis animal model in the state of lower nutrition and lower calcium in its food and soft water hardness in its drinking water (in low nutrition state for short) to mimic the living conditions of the residents in most endemic fluorosis areas of China and with the help of the rat model to observe the toxicities of fluoride to rat's teeth, bones and DNA and to evaluate the protective effects of soybean milk and cow's milk against fluoride poisoning compared to the intervention measure of improved water source.Methods1. Animals and their grouping1.1 Chronic fluorosis rat model in low nutrition stateSodium fluoride was administered to female Wistar rats through drinking water with three doses of 0. 03, 65, 100 mgF'/L for a period of 6 months. Twenty -four 80g(67 -93g) healthy female Wistar rats were randomly divided into control, middle fluoride and high fluoride groups, 8 rats in each group. Rats were feeded with feed lacking fish and bone powders. The normal waterused in the experiment was made of tap water and distilled water in a certain ratio with water hardness of 179 mg/L. The fluorinated water was made of the normal water and sodium fluoride.1.2 Thirty-two 80 g ?lOg healthy female Wistar rats were divided into control, low F, middle F, and high F group with 0, 25,50, and 100 mgFVL in distilled water, respectively. Fed the rats with ordinary rat feed. After 3 months the ultrastructures of the rats' lumbar vertebral cancellous bone were observed with a scanning electron microscope.1.3 Animal grouping in the intervention experimentsFifty-six 80g(67-93g) healthy female Wistar rats were divided into control group, soybean milk control group, cow's milk control group, fluoride group (65mgFVL) , soybean milk (intervention) group, cow's milk (intervention) group, and improved water group with 8 rats in each group. Rat feed were lack of fish and bone powders. The control rats drank the normal water as mentioned in 1. 1. Soybean milk control drank the normal water and fresh soybean milk of average 6ml daily. Cow's milk control drank the normal water and fresh cow's milk of average 6ml daily. Improved water group drank fluorinated water in the first 4 months and the normal water without fluoride in the last two months. After 6 months the rats were killed for various samples.2. Fluorine ion selective electrode method was used for measurements of rats' serum, bone, and urine fluoride concentrations.3. Damage degrees of rat's dental fluorosis were evaluated according to the method mentioned in Table 1-1 and Figures 1-1 to 1-7.4. The ultrastructure changes of the rats' lumbar vertebral cancellous bone were observed with scanning electron microscopy.5. Bone biological mechanical functions were measured with an electron u-niversal material test machine. The markers were bend maximum load and pressure maximum load in Newton.6. Urine 8-OHdG content of 24-hour was tested with ELJSA. SCGE was used to check the DNA single chain damage in rat lymphocytes.7. Activity of red blood cell SOD was tested with the xanthine oxidase method. Blood GSH concentration and activity of blood GSH-Px were measuredwith DTNB methods.8. StatisticsSPSS 11.5 for Windows software was used to gather and coordinate the experimental data. Levene's test of homogeneity of variance, One-Way ANOVA, LSDNGames-Howell,Pearson correlation analysis,and x test were used for various data analyses. Microsoft Excel 2000 software was used to make up statistic figures.Results1. A drinking water-type chronic fluor...