Objective Carbonic anhydrase 1 (CA1) not only enhances the hydration reaction but also promotes the formation of CaCO3,which is an essential step for new bone formation in vitro.However,there is no direct evidence to demonstrate the involvement of CA1 in bio-mineralization in cells and tissues.This study is aimed to evaluate the important role of CA1 in bio-mineralization and ossification in cultured cells.Methods Calcification in Saos-2 cells was induced using osteogenic medium (OM) and the calcification was determined by Alizarin Red-S staining.The expressions of ossification protein marker Runt-related transcription factor-2 (Runx2),osterix (OSX),alkaline phosphatase (ALP),osteocalcin (OCN) and bone sialoprotein (BSP) were detected in the process of bone formation by real-time PCR.The expression of CA 1 in the calcified cells were measured using real-time PCR and Western blotting.We also detected calcification in Saos-2 cells in the presence of acetazolamide,an anti-carbonic anhydrase drug to CA1,to determine the role of CA1 in biomineralization in culture cells.T test analysis was used to compare the two groups,M-ANOVA of repeated measurs was conducted for different time point.Results Following the stimulation of OM,Saos-2 cells produced a great amount of calcium-rich deposits [0.68±0.03 vs 2.76±0.13,P＜0.01].Increased transcriptions of ossification protein markers were also detected in these stimulated Saos-2 cells,indicating that the OM launched the process of bone formation in the cells.CA1 had a significantly increased expression during this process [0.25±0.03 vs 0.94±0.06,P＜0.01].Following treatment with acetazolamide,the expression of CA1 evidently declined [1.09±0.05 vs 0.55±0.07,P＜0.05],and the mineralized nodule formation was declined [2.76±0.13 vs 2.19±0.07,P＜0.01].Conclusion These findings indicate that CA1 participates in the biomineralization and ossification,and may play an important roles in bone formation.

Objective To investigate the effect of blood flow restriction combined with low-intensity plyometric jump training(LI-PJT+BFR)on lower limb dynamic postural control of functional ankle instability(FAI)in college students. Methods From March to May,2023,40 FAI college students were recruited from Xi'an Physical Education University,and randomly divided into high-intensity plyometric jump training(HI-PJT,n = 14)group,low-intensity plyomet-ric jump training(LI-PJT,n = 13)group and LI-PJT+BFR group(n = 13).All the groups finished the six-week corresponding training.The maximum voluntary isometric contraction(MVIC)of tibialis anterior,peroneus lon-gus,lateral head of gastrocnemius,gluteus maximus,vastus lateralis,biceps femoris and semitendinosus were measured,and the root mean square(RMS)of electromyography of these muscles was measured during the sin-gle-leg landing(SLL),using wireless surface electromyography before and after intervention.Moreover,they were assessed with Y-balance test and Cumberland Ankle Instability Tool(CAIT). Results MVIC and RMS of the target muscles improved after intervention in all the groups(t>2.218,P<0.05),except MVIC and RMS of peroneus longus,gluteus maximus,biceps femoris and semitendinosus in LI-PJT group,and RMS of peroneus longus in LI-PJT+BFR group;and MVIC and RMS of the target muscles were the least in LI-PJT group(F>3.262,P<0.05),except those of peroneus longus.The extension scores of Y-balance test and the total score improved after intervention(t>2.485,P<0.05),and they were the least in LI-PJT group(F>5.042,P<0.05).The CAIT score improved after intervention(t>5.227,P<0.001),and it was the least in LI-PJT group(F = 4.640,P<0.05). Conclusion LI-PJT+BFR could improve lower limb dynamic postural control of FAI college students,which is similar to HI-PJT.

ObjectiveTo explore the effect of hip neuromuscular training on reducing the risk of anterior cruciate ligament (ACL) injury in female soccer players. MethodsFrom March to May, 2022, 39 female soccer players from Xi'an Physical Education University were randomly divided into control group (n = 19) and experimental group (n = 20). On the basis of daily training, the control group received sham intervention, and the experimental group received hip neuromuscular training, for six weeks. Before and after training, they were measured dynamic knee valgus (DKV) angle and assessed with Landing Error Score System (LESS); while they were also measured the maximal voluntary isometric contraction (MVIC) and root mean square (RMS) of electromyography as single leg landing of gluteus medius and gluteus maximus. ResultsAll the indexes varied little after training in the control group (|t| < 1.178, P > 0.05), while the indexes improved in the experimental group (|t| > 2.288, P < 0.05), except sagittal score of LESS; and all the indexes improved more in the experimental group than in the control group (|t| > 2.609, P < 0.05), except sagittal score of LESS and MVIC of gluteus maximus. ConclusionHip neuromuscular training can reduce the risk of ACL injury in female soccer players.