Effects Of Bone Metabolism And Bone Microstructure Mediated By The Change Of Estrogen With Coal-burning Fluorosis

Part 1: Establishment and identification of a female rat model of coal-burning fluorosisObjective: To establish a female model of coal-burning endemic fluorosis with strong operability and obvious pathological characteristics,and lay a solid model foundation for subsequent mechanism research.Methods: 150 SD female rats were cleaned at 2 weeks of weaning.After 1 week of adaptive feeding,they were randomly divided into 5 groups: control group,low-fluoride group,medium-fluoride group,high-fluoride group,and ovariectomized group.Each group 30.The rats were fed with different fluorine content(0,25,45,110,0 mg / kg)for 150 days.Female rats were weighed monthly to observe and record the occurrence of fluoride plaque.10 rats/group were killed at 90,120,and 150 days after modeling.Urine was collected before execution,and the fluoride content in urine was measured by a fluoride ion electrode method.The femoral bones of the right lower limbs of the female rats were taken,and the bone fluoride content was measured by high temperature ashing method.Results: No fluorosis occurred in the control group and the ovariectomized group.There was a linear correlation between the degree of fluoride plaque damage and the dose(?2= 6.273,P<0.05).Except for the low-fluoride group,the urine fluoride content in the residual-fluorinated group was higher than that in the control group(P<0.05),and increased with time and the dose of fluorine-exposure increased.The bone fluoride content of female rats in the fluoride-exposed group was higher than that in the control group(P<0.05),and increased with the prolongation of the fluorine-exposure time and the increase of the fluoride-exposure dose.The sex cycle of the ovariectomized rats stayed in the estrus interval.Conclusion:A female model of coal-burned endemic fluorosis and an ovariectomized rat model were successfully established.Part 2: Effects of coal-burning fluorosis on sex hormones,bone metabolism and bone microstructure in female ratsObjective: To investigate the possible effects of fluorosis on E2,bone metabolism and bone microstructure by detecting changes in serum E2,bone metabolic factor content and bone microstructure parameters of female rats in each group.Methods: After centrifuging the serum of female rats in each group,the serum E2 content was determined by radioimmunoassay,and the serum bone metabolic factors and IGF-1 content of ovarian tissue homogenate of each group were measured by enzyme-linked immunosorbent assay.Microscopic CT was used to detect BMD and other bone microstructural parameters of the left femur in each group of rats.Results: 1?Changes in E2 and its mechanism: At 90 days,the serum E2 of the rats in the middle and high fluoride group was higher than that in the control group and the low fluoride group,and the difference was statistically significant(P<0.05).At 120 days,the serum E2 of the rats in each fluoride group was all Compared with the control group,the difference was statistically significant(P<0.05).At 150 days,the serum E2 of the high-fluoride group was significantly lower than that of the control group and the low-fluorine group(P<0.05).In the high-fluoride group,the serum E2 of late period was significantly lower than 90 days,and the difference was statistically significant(P<0.05).At 120 days,the expression of ovarian IGF-1 in the middle and high fluoride group was lower than that in the control group(P<0.05),and the high fluoride group was lower than the low fluoride group(P<0.05).At 150 days,the expression of IGF-1 in the ovaries of the rats exposed to fluoride was lower than that in the control group(P<0.05).In the middle and high fluoride group,the expression of ovarian IGF-1 of the middle and late period was lower than the early level(P<0.05).2 ? Bone metabolism factor changes: At 150 days,BALP of female rats in the high-fluoride group was significantly lower than that in the normal control group and the low-fluoride group(P<0.05),and the BALP content of female rats in the medium-high fluoride group decreased in the late stage of fluorine exposure(P<0.05);At 90 days,the serum TRACP-5b content of female rats in the medium and high fluoride group was lower than that of the control group(P<0.05).At 120 days,the serum TRACP-5b content of each fluorine-treated group was higher than that of the control group(P<0.05),with a dose-dependent effect.At 150 days,the levels of TRACP-5b in the serum of the rats exposed to fluoride were higher than those of the control group(P<0.05),and that of the medium fluoride group was higher than that of the low fluorine group(P<0.05).The levels of TRACP-5b in rat serum were higher than the early levels at 120 and 150 days after fluoride exposure(P<0.05);In the IGFs family,female mice in the ovariectomized group had lower serum IGF-1 and IGFBP5 than the normal control group(P<0.05),and IGFBP4 was higher than the control group(P<0.05).At 120 days,IGF-1 in the high-fluoride group was lower than the other groups(P<0.05),and in the medium-fluoride group was lower than that in the low-fluoride group(P<0.05).At 150 days,the serum IGF-1 levels of the rats in the middle and high fluoride group were lower than those in the control group and the low fluorine group,and the difference was statistically significant(P<0.05),and the high fluoride group was lower than the medium fluorine group(P<0.05).The serum IGF-1 content of female rats: 90d>120d>150d,the differences were statistically significant(P<0.05).At 90 days,IGFBP4 was higher in the medium-fluoride group than in the low-fluoride group(P<0.05).At 120 days,IGFBP4 was higher in the middle-high-fluoride group than in the control group and the low-fluorine group,and the differences were statistically significant(P<0.05).At 150 days,the IGFBP4 levels of the rats in each fluorine-treated group were higher than those in the control group(P<0.05),and there was a dose-dependent effect.The IGFBP4 content of the rats in the medium and high fluoride group: 90d<120d<150d,the differences were statistically significant(P<0.05).At 150 days,the content of IGFBP5 in the middle and high fluoride group was lower than that in the control group and the low fluorine group(P<0.05),and was higher than that at 90 days(P<0.05).3?At 90 days,the BMD in the high-fluoride group was higher than that in the control group and the low-fluorine group,and the differences were statistically significant(P<0.05).At 120 days,the BMD in the low-fluoride group was greater than the control group(P<0.05),the BMD of the rats in the middle and high-fluoride group was lower than that in the low-fluoride group(P<0.05),and the BMD of the rats in the high fluorine group was lower than that of the control group and the medium fluorine group(P<0.05).At 150 days,the BMD of the rats in the low-fluoride group was higher than that in the control group(P<0.05),and the middle and high-fluoride group decreased as the dose increased.The BMD of the rats in the low-fluoride group: 90d<120d<150d,the differences were statistically significant(P<0.05),the middle and high fluoride groups were the opposite.TMD changes in rats were consistent with BMD.The BV/TV of low-fluoride group was higher than the control group(P<0.05),the middle-high fluorine group was higher than the control group at 90 days(P<0.05),and the high-fluoride group higher than medium fluoride group(P<0.05),and at 120 d and150d,it was lower than the control group(P<0.05),and the medium fluorine group higher than high fluorine group(P<0.05).BS/BV: At 90 days,the high-fluoride group was higher than the control group and the low-fluoride group(P<0.05),and at 150 days,each fluorine-treated group was lower than the control group(P<0.05).BS / TV: At 90 days,the medium and high fluorine group was higher than the control group(P<0.05),and at 150 days,the high fluorine group was lower than the medium fluorine group(P<0.05).Tb.Sp: At 90 days,the low and medium fluorine groups were lower than the control group(P<0.05),and at 120 and 150 days,the medium and high fluorine groups were higher than the control group(P<0.05),with a dose-dependent effect.Tb.N: at 90 days,the fluoride-exposed groups were higher than the control group(P<0.05),and at 120 and 150 days,the medium-high fluoride group was lower than the control group(P<0.05),with a dose-dependent effect,and the low-fluoride group Higher than the control group(P<0.05).Tb.Th: At 90 days,each fluorine-treated group was higher than the control group(P<0.05),and at 150 days,the medium-high fluoride group was lower than the low-fluorine group(P<0.05).Conn.D: Conn.D of fluorosis rats was lower than that of the control group,and the differences were statistically significant except for 150 days(P <0.05).SMI: at 90 days,the middle and high fluoride groups were lower than the control group(P <0.05),and the opposite was observed at 120 days and 150 days.DA: At 90 days,the middle and high fluoride group was lower than the control group and the low fluorine group,and the difference was statistically significant(P <0.05).Tb.Pf: at 90 days,the control group> medium fluoride group> high fluorine group(P <0.05),at 120 days and 150 days,the low fluorine group was lower than the control group(P <0.05),and the medium and high fluorine group was higher than Fluoride group(P <0.05).Conclusion: 1.Fluorosis may reduce E2 secretion by down-regulating the expression of IGF-1 in ovarian tissue.2.Fluorosis has two-way effect on the bone turnover of female rats.3.The effects of fluorosis on the bone microstructure of female rats are two-way.Part 3: Effects of bone metabolism and bone microstructure mediated by the change of estrogen with coal-burning fluorosisObjective: To investigate the effects of changes in E2 levels of female rats caused by fluorosis on bone metabolism factors and bone microstructure.Methods: Bivariate correlation analysis was performed on the dose of fluoride,the serum E2 level of female rats and the bone metabolism factors to determine the rationality of the regulatory effect analysis.The process plug-in was used to incorporate the fluorine exposure dose and female mouse serum E2 level into the independent variables.Multiple regression analysis was performed using each bone metabolic factor as the dependent variables.The significant level of the interaction term "fluorine exposure dose * E2" was tested to determine the existence of moderating effect,and the mode of action.Results: 1?Female rats E2 content plays a positive role in the relationship between the dose of fluoride and serum IGF-1(?=0.301,P<0.05),which can explain the 11.9% serum IGF-1 variation alone.Decreased E2 content will increase the inhibitory effect of fluoride on serum IGF-1 expression,and this effect is more pronounced as the E2 content decreases progressively(slope from-0.081 to-0.682,P<0.05).2?Female rats E2 content negatively regulates the relationship between fluoride exposure and serum IGFBP4(? =-0.261,P<0.05).This regulation can explain 9% serum IGFBP4 variation alone,and decreased E2 content will increase the up-regulation effect of fluoride on serum IGFBP4,and with the progressive reduction of E2 content,this enhancement effect is more obvious(slope from 0.230 to 0.752,P<0.05).3?The positive regulation effect of E2 content in female mice's body on the relationship between the dose of fluoride and serum IGFBP5(?=0.175,P = 0.056)is marginal.After analysis by Johnson-Neyman method,except that the regulatory effect does not exist when E2=38.71ng/dl,a decrease in E2 content will enhance the inhibitory effect of fluoride on serum IGFBP5.4?Female E2 content negatively regulates the relationship between the dose of fluoride and serum TRACP-5b(?=-0.218,P<0.05),which can explain the 6.3% serum TRACP-5b variation alone.Decreasing the content will enhance the promoting effect of fluoride on serum TRACP-5b,and this effect will be more obvious as the content of E2 decreases progressively(slope from 0.201 to 0.637,P<0.05).5 ? There was no regulating effect of E2 content in female rats' serum on the relationship between fluoride exposure and serum BALP(?= 0.088,P = 0.379).6.?Female E2 content can regulate the relationship between the dose of fluoride and bone mass and morphology of bone trabeculae.Conclusion: Decreased E2 content in female rats caused by fluorosis can further down-regulate the expression of growth factors IGF-1 and IGFBP5 in the IGFs family and up-regulate the expression of IGFBP4,and at the same time further promote bone resorption activity,affect bone turnover,and lead to bone microstructure changes Bone skeletal disease occurs.