I-型胶原C末端肽与骨钙素N-MID片段测定在AS继发骨质疏松中的意义

目的探讨I-型胶原C末端肽与骨钙素N-MID片段测定在AS继发骨质疏松中的意义。方法选取强直性脊柱炎（AS）患者43例（AS组）与正常人32例（对照组）,分别用双能X线测定骨密度、ELISA方法测定I-型胶原C末端肽与骨钙素N-MID片段。结果 AS组患者中,股骨颈骨密度、L2-4与L1-4骨密度分别为（0.888±0.113）g/cm2、（1.057±0.183）g/cm2、（1.097±0.187）g/cm2,均低于对照组的（0.953±0.117）g/cm2、（1.121±0.165）g/cm2、（1.128±0.159）g/cm2（P〈0.05）。31例AS患者诊断为骨质疏松,AS组I-型胶原C末端肽水平为（3079.0±490.2）ng/L,高于对照组的（1071.1±535.5）ng/L（P〈0.05）。骨钙素N-MID片段水平为（23.5±12.2）ng/mL,低于对照组的（36.3±18.8）ng/mL（P〈0.05）。结论骨吸收增加与骨形成减少均可能是AS继发骨质疏松的机制。

Significance of C-telopeptides of Type I collagen (CTX-I) and N-MID osteocalcin in osteoporosis secondary to ankylosing spondylitis

Objective To investigate the significance of measurement of C-telopeptides of TypeⅠcollagen（CTX-I） and serum N-MID osteocalcin in osteoporosis secondary to ankylosing spondylitis（AS）.Methods Bone mineral density（BMD） was determined using dual-energy X-ray absorptiometry（DEXA） in 43 AS patients and 32 healthy subjects.Serum CTX-I and N-MID osteocalcin were measured by ELISA..Results In AS group,BMD of the proximal femur and the anteroposterior spine were significantly lower than those in the control group（0.888±0.113 vs 0.953±0.117 g/cm2 proximal femur,1.057±0.183 vs 1.121±0.165 g/cm2 L2-4 and 1.097±0.187 vs 1.128±0.159 g/cm2 L1-4;P0.05）.31 patients in AS group were clinically diagnosed as osteoporosis.The CTX-I in the AS group was higher than that in the control group（3 079.0±490.2 vs 1 071.1±535.5;P0.05）.But the N-MID osteocalcin in AS group was lower than that in the control group（23.5±12.2 vs 36.3±18.8;P0.05）.Conclusion Increase in the bone absorption and decrease in bone formation are the underlying mechanism of osteoporosis in AS.