| Background: The rising rate of overweight and obesity among adolescents has become an important public issue affecting adolescent health.Some obese teenagers even develop metabolic disorders and develop metabolic syndrome.Studies have found that excessive accumulation of fat can lead to abnormal metabolism in the body,which in turn causes bone metabolism disorders and bone loss,thereby affecting bone health.As an important member of the endocrine FGFs subfamily,FGF23 is mainly synthesized by osteocytes and osteoblasts,and is involved in regulating the metabolism of vitamin D,PTH and phosphorus in the body.FGF23 needs to participate in the regulation of calcium and phosphorus metabolism by forming a FGF23-αKlotho-FGFR1 ternary complex with cofactor αKlotho and receptor FGFR1,and then participate in the regulation of bone metabolism.Objective: In this study,the aim of this study was to investigate the effect of exercise and dietary intervention on serum FGF23 levels and its related metabolic markers in obese boys of adolescents.Additionally,the role of the FGF23-αKlotho-FGFR1 axis in bone metabolism in obese adolescents was further analyzed.Subjects: Fifteen obese adolescents aged 12-18 were selected from the campers of Wuhan Haoqian Weight Loss Training Camp as research subjects,and the subjects were divided into metabolic syndrome obesity group（MSO group,n=7）and Non-metabolic syndrome obesity group（NMSO group,n=8）.Another 8 normal-weight adolescents aged 12-18 were selected as the control group（group C）.Methods: Both the MSO group and the NMSO group underwent a 4-week exercise combined with diet intervention in a centralized closed state.Tests were performed on the 1st day of camp and the 4th weekend after the intervention.The test content includes body shape,body composition,bone density and related blood biochemical indicators.Body composition was measured using an electrical impedance body composition meter.Bone density was measured using ultrasound absorptiometry.Biochemical indicators such as calcium and phosphorus metabolism indicators and glucose and lipid metabolism indicators were determined using an Automatic Biochemical Analyzer and Electrochemiluminescence Immunoassay Analyzer.An enzyme-linked immunosorbent assay（ELISA）is a method to test for FGF23,αklotho,and FGFR1.SPSS23.0 is the software for data analysis.Results:（1）Body weight,fat percentage,body fat mass,BMI,inorganic salt content,waist circumference,bust circumference,hip circumference and waist-to-hip ratio in MSO group and NMSO group were signiicantly higher than those in group C before combined intervention（P<0.001）.However,these indicators were not signiicantly different between the two obesity groups.The body weight,BMI,fat percentage,body fat mass,hip circumference,waist circumference,and abdominal circumference of the subjects in the MSO group and the NMSO group were signiicantly decreased after the combined intervention（P<0.001）.Waistto-hip ratio was also signiicantly decreased,but there was a slight difference between the two groups（MSO group P<0.01,NMSO group P<0.001）.Overall,central obesity was effectively improved;（2）TG,LDL-C and resting heart rate in MSO group and NMSO group were signiicantly higher than those in C group before combined intervention（P<0.01）.There were no signiicant differences between the two groups in these indicators of obesity.Before intervention,the insulin resistance index of MSO group was signiicantly higher than that of NMSO group（P<0.05）and C group（P<0.001）.The insulin resistance index of NMSO group was signiicantly higher than that of C group（P<0.01）.The subjects in both MSO group and NMSO group were in the state of insulin resistance,but the degree of insulin resistance in the MSO group was stronger than that in the NMSO group.TC,LDL-C,TG and resting heart rate in MSO group and NMSO group were signiicantly decreased after combined intervention（P<0.05）,but HDL-C was signiicantly increased（P<0.05）.The systolic blood pressure and diastolic blood pressure were signiicantly decreased in the NMSO group（P<0.05）,but there was no signiicant change in the MSO group;（3）The serum 1,25（OH）2D3,PTH,P and calcium-phosphorus product of MSO group and NMSO group were signiicantly lower than those of C group before intervention（P<0.05）.1,25（OH）2D3 in MSO group was signiicantly lower than that in NMSO group（P<0.05）.The levels of serum 1,25（OH）2D3（P<0.05）,calcium-phosphorus product,PTH（P<0.001）and P（MSO group P<0.01,NMSO group P<0.001）in MSO group and NMSO group after combined intervention were signiicantly increased,but there was no signiicant difference between the two obese groups;（4）Bone index,T value and Z value in MSO group and NMSO group were signiicantly lower than those in C group before intervention（MSO group P<0.05,NMSO group P<0.001）.The osteopenia in the two groups accounted for 66.67%,but there was no signiicant difference between the two groups.After the combined intervention,the bone index,T value and Z value of the MSO group and the NMSO group were signiicantly increased（P<0.001）.The osteopenia of the two groups decreased to 13.34%,but there was no signiicant difference between the two groups;（5）The serum FGF23 and Klotho levels in MSO group and NMSO group were signiicantly higher than those in C group before intervention（P<0.01）.Serum FGFR1 levels were signiicantly lower than those in group C before intervention（P<0.05 in MSO group,P<0.01 in NMSO group）.The serum concentrations of FGF23,Klotho and FGFR1 in MSO group and NMSO group were signiicantly decreased after intervention（MSO group FGF23,Klotho P<0.001,FGFR1 P<0.01;NMSO group FGF23,Klotho P<0.01,FGFR1 P<0.05）,However,there was no signiicant difference between the groups.The levels of FGF23 in both groups were still signiicantly higher than those in group C after intervention（P<0.05）.There was no signiicant difference in Klotho level between MSO group and C group after intervention,but NMSO group was signiicantly higher than C group（P<0.05）.The level of FGFR1 in the two groups after intervention was signiicantly lower than that in group C（P<0.001）.Conclusion: Obese adolescents develop disorder of glucose and lipid metabolism accompanied by decreased bone status.Glycolipid metabolism is more disturbed in obese people with metabolic syndrome than those with non-metabolic syndrome.Combined intervention can effectively improve central obesity and bone status in obese adolescents.Combined intervention reduces the level of FGF23 in obese adolescents,possibly through the FGF23-αKlotho-FGFR1 axis,regulates calcium and phosphorus metabolism,and improves bone condition. |
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