Objective: To explore the remodeling effect of a 12 week supervised exercise intervention on the relative proportion of body composition among junior and senior high school students with obesity using compositional data analysis (CoDA), to clarify the longitudinal association between body composition changes and the improvement of metabolic syndrome (MetS), and to identify the core body composition targets for ameliorating metabolic risk in adolescents. Methods: A randomized controlled trial design was employed in March 2025. Totally 182 obese adolescents aged 12-18 years from two junior and senior high schools in Tianjin were recruited and randomly assigned to an exercise intervention group ( n =92) and a health education control group ( n =90) at a 1∶1 ratio. The intervention group received a 12 week supervised aerobic combined with resistance exercise intervention (4 sessions/week, 60 min/session), while the control group only received routine health education concurrently. Body composition was determined using 3.0 T magnetic resonance imaging. With students sex specific MetS Z score as the core outcome, compositional data were processed via isometric log ratio transformation. Statistical tests were performed combining repeated measures MANOVA, multiple linear regression, and analysis of covariance. Results: After the intervention, the overall body composition of the intervention group changed significantly ( F =18.72, P <0.01), with the relative proportion of visceral fat decreasing the most (change the isometric logratio: -0.17), and the betweengroup difference was statistically significant ( P <0.01). The relative mass of visceral fat before and after the intervention was positively correlated with the MetS Z score (before intervention: β =1.02, 95% CI =0.06-1.98; after intervention: β =1.42, 95% CI =0.58-2.26, both P <0.05), and there was no statistically significant difference in the slopes and intercepts of the regression models between the two time points (both P >0.05). When the magnitude of weight loss was fixed, a greater relative reduction in visceral fat was associated with a more significant decrease in the MetS Z score. Conclusions The relative proportion of visceral fat is a core stable marker for MetS risk in obese junior and senior high school students. A 12 week supervised combined exercise intervention can effectively reduce the proportion of visceral fat and improve the risk of metabolic syndrome among junior and senior high school students.

Objective To study the effects of fluoride on longitudinal growth and pathological changes of cultured rat metatarsal bone rudiments.Methods Twenty-four neonatal SD rats were divided into four groups according to the random number table,then the second,third and fourth metatarsal bone rudiments were surgically isolated.The left metatarsal bone rudiments were cultured in α-MEM without F-as control group and the right metatarsal bone rudiments from the same rat were cultured in α-MEM with 1 × 10-7,1 × 10-6,1 × 10-5 and 1 × 10-4 mol/L F-.The length and width of the mineralized area of metatarsal were measured on day 0,day 1,day 4 and day 7,respectively,and the pathological changes of metatarsal bone rudiments were observed by the routinely paraffin-embedded sections method on day 7.Results On day 7,the length of the mineralized area was significantly lower of right metatarsal bone [(240.5 ± 139.3)μm] than the left metatarsal bone [(394.1 ± 173.9)μm,t =4.37,P ＜ 0.01] in the 1 × 10-4 mol/L F-group,but the width of the mineralized area [(239.9 ± 119.4)μm] was not different significantly compared to the left metatarsal bone [(223.3 ± 99.9)μm,t =0.44,P ＞ 0.05].The relative vertical growth rate of the mineralized area on day 4 was significantly lower of right metatarsal bone [(2.43 ± 1.44)％] than left metatarsal bone [(8.34 ± 1.74)％,t =3.21,P ＜ 0.01] in 1 × 10-4 mol/L F-group,and the difference was also significant on day 7 [(16.16 ± 2.87)％ vs.(26.52 ± 4.46)％,t =3.13,P ＜ 0.01].Toluidine blue staining results showed that the thickness of cartilage cells of proliferation and hypertrophic layers was significantly lower of right metatarsal bone [(111.33 ± 27.29),(125.33 ± 30.08)μm] than left metatarsal bone [(127.33 ± 38.36),(160.50 ± 42.73)μm,t =4.82,5.81,all P ＜ 0.01] in 1 × 104 mol/L F-group.The ratio of proliferative and hypertrophic layers was significantly higher of right metatarsal bone (0.93 ± 0.36) than left metatarsal bone (0.83 ± 0.32,t =4.42,P ＜ 0.01) in 1 × 10-4 mol/L F-group.Conclusions Our findings indicate that excessive fluoride could cause longitudinal bone growth inhibition.Such growth inhibition is mediated by decreased chondrocyte proliferation and differentiation and the disproportion of proliferation and differentiation.

Objective To study the changes of negative symptoms in PCP-induced schizophrenia rat model.Methods Thirty newborn female SD rats randomly divided into control group,PCP-week 6 group and PCP-week 10 group( n=10 in each group).Perinatal rat treated with PCP ( 10 mg/kg) on postnatal days 7,9 and 11(10 mg/kg,ip),and sucorse intalce test(SIT),forced swimming test(FST) and resident-intruder test(RIT) were used to test the emotional and negative symptoms.Results In the SIT,there was no difference between control and PCP groups (con:(28.24 ±0.86) ml/kg; week 6:(26.57 ± 1.01 ) ml/kg; week 10:(27.98 ±0.99) ml/kg,F =12.35,P ＞ 0.05 ).In the FST,PCP model rats showed longer still time ( con:(39.32 ± 1.98 ) s ; week 6:(52.39 ± 1.66)s,week 10:(55.56 ± 1.49)s,F=3.99,P＜ 0.05 ).In the RIT,PCP models rats showed less explore time ( (40.31 ± 13.56)s vs (63.90 ± 13.12)s,(43.65 ±12.86 )s vs (65.18 ± 15.12)s,P ＜ 0.05 ) and more escape time ((19.33±2.26) s vs (9.26 ± 1.32) s,(17.79 ±2.99) s vs (9.38 ± 1.36) s,P＜ 0.05).Conclusion Perinatal PCP injection can induce the long-lasting negative-symptoms changes.