| Fluorine is a toxicant widely distributed in nature,and it is the most electronegative metallic element among the nonmetalloid. As an essential trace element,people could exposure to fluoride through a variety of sources such as water, soil and air.Long-term excess intake of fluorine can cause skeletal fluorosis and dental fluorosis so far as to damaged the ndocrine system,nervous system,urinary system and reproductive system. The universality and complexity effect of chronic fluorosis on reproductive system have been taken seriously by Scholars both at home and abroad.It has already bacame a urgent subject of drugs for exploring the treatment of fluorosis.Selenium is an essential trace element of the human body with strong antioxidant effect, effects of selenium of the human body on fluorosis have been recognized by many scholars. Epidemiological investigations and animal experiments have shown that a certain dose of selenium can alleviate fluorosis, promote the excretion of urinary fluoride, correct the oxygen free radicals and lipid metabolism disorder,significantly inhibit the fluoride-induced lipid peroxidation. Reports about the antagonistic effects of Selenium on fluoride confirmed that there are protective effects of selenium on phrenology, non-phrenology injury induced by fluorosis, but the studies on reproductive toxicity are still lack of in-depth and systematic. In addition, in order to seek both the best anti-fluoride effect without producing toxic effects of selenium dose, it is necessary to find smaller, more secure selenium anti-fluoride dose on the basis of1.5mg/L dose of the early sub-chronic institute.Methods:The experiment was divided into:antagonism groups, prevention groups and treatment groups:(1) antagonism groups:240Sague-Dwley (SD) rats were randomly divided into8groups of30each. The control group drank tap water, fluoride group drank50mg/L of sodium fluoride solution,3selenium-infected groups drank0.375mg/L,0.75mg/L,1.5mg/L of sodium selenite solution,3fluorine+selenium groups drank a combination of two of the50mg/L sodium fluoride and the three kinds of concentration of sodium selenite, and the exposure time were6months.(2) prevention groups:120SD rats were randomly divided into4groups of30each. Fluoride-after-water control group drank tap water before50mg/L of sodium fluoride solution.3fluoride-after-selenium groups were asked to drink3concentrations of sodium selenite solution above, then50mg/L sodium fluoride solution, and all the handling time were6months.(3) treatment groups:120SD rats were randomly divided into4groups of30each. Water-after-fluoride control group drank water before50mg/L of sodium fluoride solution.3selenium-after-fluoride groups were asked to drink50mg/L of sodium fluoride solution, then3concentrations of sodium selenite solution, exposure for6months.Each group of experiments use rat organ coefficient, histopathology sections, the enzyme activity and sperm DNA damage of sperm and other indicators as the observation point,we can make a comprehensive evaluation about the effects of selenium in the prevente, antagonist and treatment of reproductive toxicity due to chronic fluorosis by drinking water and find out the best anti-fluoride dose of selenium, And prove trends of combined exposure of fluorine and selenium on the male reproductive system, and further reveal selenium’s intervention mechanism of the male reproductive system damage caused by fluoride, evaluation the effect of combined exposure to different enzymes,through these can explore the molecular targets of reproductive toxicitypoint, and provide the scientific basis for endemic fluorosis, especially the prevention and treatment of the male reproductive system damage induced by fluoride. Results:1. Antagonism groupsThe rats in different groups were no obvious abnormalities or death during the study. Compared with contrl group,weigh of rats was significantly increased (P<0.05) in group of fluorine plus low-dose selenium and fluorine plus mid-dose selenium.Compared with the control group, the LDH activity,AKP activity,and SOD activity of fluoride group were significantly lower (P<0.05), the ACP activity was significantly increased (P<0.05); the level of AKP was significantly (P<0.05) increased in mid-dose selenium, the Na+, K,+-ATPase activity of high-selenium group and fluorine with high-dose selenium group are significantly lower, in the mid-dose selenium group and fluorine heightening selenium group,the Ca2+-ATPase activity are also significantly decreased(P<0.05);the pathological structure and sperm DNA of exposed groups are in a certain degree of damage. Compared to fluoride group,the LDH activity of the mid-dose selenium group, the high selenium group,and the fluoride with heightening selenium groupwere significantly increased (P<0.05). The results above showed that0.75mg/L of selenium have the best antagonism in treat the reproductive toxicity of rats caused by chronic fluorosis.2. Prevention groupsCompared with the control group, the activity of LDH、AKP、SOD was significantly (P<0.05) increased in fluoride-after-low-dose selenium group while the activity of GSH-Px was significantly (P<0.01) increased; Similar significant (P<0.01) increased was found in the activity of ACP in all the fluoride-after-selenium groups respectively. In fluoride-after-mid-dose selenium group, GSH-Px activity very significantly increased (P<0.01), Ca2+-ATPase activity was significantly increased (P<0.05); The ACP activity of the three fluoride after selenium group were significantly increased (P<0.01). It point out that medium and low concentrations of selenium have better prevention effect in antagonism fluorine.3. Treatment groupsCompared with the water after fluoride group,the activity of LDH was significantly (P<0.01) increased in low-dose selenium-after-fluoride group. Significant increase (P<0.05) in the activity of Na+K+-ATPase was observed in the mid-selenium after fluoride group; while the activity of Ca2+-ATPase increased more significantly(P<0.01).In summary, echronic exposure to fluorid by drinking water can injure each respect index of reproductive system, the activity of antioxidase decreased, testis structure and DNA in sperm damaged, ang then may affect the normal reproductive activity.Selenium can produce a certain impact on male reproductive toxicity caused by fluorosis. In this experimental conditions,0.375mg/L of selenium has the best preventive effect on reproductive toxicity caused by chronic fluorosis, and0.75mg/L of selenium has a good antagonism and treatment effect. Different enzymes have different sensitivitis in the antagonism, preventive and treatment. LDH may be one of the drug targets of intervention of selenium to fluorosis. The results provide a certain amount of research data to further explore the mechanism on molecular leve of selenium intervention to the male reproductive toxicity caused by fluorosis. |
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