| Fluorine is a non-metallic element, also a essential trace element to human beings. But long-term excessive intake of fluoride will occur fluorosis to the body, which damage a variety of tissues and organs. At present the study on fluorosis mostly are acute exposure and sub-chronic exposure, exposure period is short and the researchs are concentrated in the damage to the Skeleton system, the few studies on the blood. In this paper, to the beginning of weaning Sprague-Dawley (SD) rats were studied by using water fed manner of chronic exposure, which lasted 9 months and 18 monthsrespectively, by detecting blood routine, sialic acid content, trace elements, lipid peroxide levels in serum, the fluidity erythrocyte membrane, such as peripheral blood lymphocyte DNA damage, study of chronic fluoride poisoning on blood physiological and biochemical indexes. The major findings are as follows:1. Chronic fluorosis effect on the routine blood:Compared with the control group, the routine blood indicators of red blood cells, white blood cells and platelets in exposure group take place of pathological changes and with the time and dose of exposure increased, there has been a significant difference(p<0.05), with the exposure time increasing, compared to the same group in3-month exposure period,the indicators also changed, and with the time and dose of exposure increased, there has been significant in change(p<0.05).2. Chronic fluorosis effect on the content of sialic acid(SA):Compared with the control group, the content of SA in fluorine group increaseed in varying degrees, and the middle and high fluoride group were significantly increased(p<0.05), which was very significantly increased(p<0.01)in high fluoride group when 18 months, and compared to 9 months, the SA content in each group have increased when 18 months, in which the middle and the high-dose fluoride group had significant difference(p<0.05).3. Chronic fluorosis effect on the trace elements:Compared with the control group, the content of trace elements Cu,Mn,Fe,Zn in both period of exposure had a downward trend, in which Cu and Mn in the middle and the high-dose fluoride group were significantly decreased(p<0.05), Fe and Zn in the fluoride group had significant difference in two period of exposure(p<0.05), these trace elements in high-dose group were tested with a very significant difference(p<0.01) in 18 months,and compared with 9 months, when 18 months trace elements in the various groups have decreased, in which the middle and the high-dose fluoride group had significant difference(p<0.05).4. Chronic fluorosis effect on the antioxidant capacity:Compared with the control group, the MDA levels of the fluoride group have seen a rise in both period of exposure, and the middle fluoride group of MDA had a significant increase(p<0.05) in exposure period of 9 months, while the content of MDA in high-dose group increased significantly(p<0.05) when 18 months, and compared to the exposure period of 9 months in the same group, the MDA content in all groups have a certain degree increased when 18 months, while high-dose group significantly increased(p<0.05); Compared with the control group, the content of UA in fluorine group increase significantly(p<0.05), of which in the middle-dose group showed very significant difference(p<0.01) when 9 month, and in the middle and the high-dose fluoride group showed very significant difference(p<0.01)when 18 months, compared with 9 months of the same group in 18 months, UA levels in all groups are on the rise, in which the middle and the high-dose fluoride group showed significant difference(p<0.05), while the control group and the low-dose group there was no significant difference(p>0.05); compared with the control group, antioxidant enzymes (SOD, GSH-Px, T-AOC) activity in the exposure period has fallen, and the existence of significant differences (p<0.05), and high-dose group were tested with a very significant difference(p<0.01) in 18 months, and the exposure period of 9 months compared to the same group, exposure period of 18 months, antioxidant enzymes activity in all groups have a certain decline, and the middle and the high-dose fluoride group had significant difference(p<0.05). low-fluorine and the control group there were no significant difference(p>0.05).5. Chronic fluorosis effect on the fluidity erythrocyte membrane:The fluidity of erytherocyte membrane was decreased with the fluorine dose increasing, and the middle and high doses group have a significant decrease after 9 months and fluoride group have a significant decrease after 18 months(p<0.05), and high-dose group were tested with a very significant difference(p<0.01) in 18 months, compared with 9 months, the fluidity of erytherocyte in the control group was no significant difference(p>0.05), the fluidity of erytherocyte membrane in fluoride group were significantly declined(p<0.05).6. Chronic fluorosis effect on the DNA damage:Compared with the control group, the rate of DNA and the DNA migration length of the tail increased significantly in fluorine group(p<0.05), and the middle and the high-dose fluoride group had very significant difference(p<0.01), compared to the same group in 9 months, the rate of DNA and the DNA migration length of the tail in each group had increased in 18 months, in which fluoride group showed significant difference(p<0.05), the control group no significant difference(p>0.05).The results above suggested that that prolonged intake of high doses of fluoride can cause anemia, reduced immunity, and lead to the body composition of trace elements in antioxidant enzymes decreased, then antioxidant enzyme activities lead to reduced, allowing an increase in oxygen free radicals and lipid higher quality of peroxide, resulting in cell DNA damage, resulting in affecting cell's normal physiological function, while the body to produce toxic effects. |
