胫骨上干骺端缓慢牵伸延长对兔膝关节软骨形态的影响

目的 探讨关节软骨是否适应肢体延长时的缓慢牵伸应力刺激。方法 32只成年新西兰兔随机分为延长组（A组）和延迟观察组（B组），各组又按延长幅度不同分为10％、20％及40％三个亚组（即A10、A20、A40、B10、B20、B40六组，每组5只），另2只为正常对照。采用胫骨上干骺端1mm／d速度缓慢牵伸延长。通过X线确定延长幅度及膝关节影像学变化，用光镜及电镜观察胫骨平台关节软骨组织及细胞形态变化，用扫描电镜观察软骨表面结构变化。结果 （1）各组术前、延长前、延长终止及取材时膝关节软骨未见明显影像学异常。（2）A40及B40组部分内侧胫骨平台软骨外观苍白、光泽差，其余各组无异常。（3）A40组细胞排列紊乱，可见散在的退变细胞及部分同源软骨细胞群；B20组及B40组细胞数量增多且胞体增大，有较多同源软骨细胞群，无退变细胞。（4）A40组部分细胞有轻度的粗面内质网扩张及线粒体肿胀，但细胞周晕正常；部分细胞粗面内质网丰富、胞周基质小泡丰富。B组表现与A组基本相似。（5）A10组软骨表面偶见形态不规则表面突起；A20组网状纤维稍紊乱；A40组出现条束状不规则粗大纤维束，偶见表面细小裂隙。与A40组比较，B40组软骨表面粗大纤维明显减少，未见表面裂隙。结论 低幅度延长时关节软骨能有效适应缓慢牵伸刺激，但大幅度延长时关节软骨会出现不同程度的形态结构异常。

Morphologic changes of arthrodial cartilage of tibial platuea during tibiae lengthening

Objective To investigate the adaptation of metabolism of arthrodial cartilage for limb lengthening. Methods Thirty New Zealand rabbits were randomized into two groups, limb lengthening group (group A) and delay observation group (group B). Every group was subdivided into three sub-groups according to distraction degree: 10%, 20% and 40%. Upper-tibia metaphysis lengthening was adopted at 1 mm/d rate of distraction and iconography changes of knee joint were observed with X-ray, the morphologic changes of chondrocyte and cartilago articularis on tibial flat were observed with light and electric microscope. The changes of cartilage surface were observed with scanning microscope. Results 1) There was no obvious iconography change of knee at every time phase in each group. 2) Pale of cartilage on tibial flat were just noted in group A40 and B40. 3) The arrangement of chondrocyte was disorder in A40, some degenerating and generating chondrocytes were found in the same group. The number of chondrocytes increased, and the volume was expanded in group B20 or B40, the degenerating chondrocytes were not found in the same group. 4) Low-grade expansion of endoplasmic reticulum and swelling of chondrosome were found in part of chondrocyte in group B40 contrasting with the other groups. The numbers of endoplasmic reticulum and matrix alveolus increased in chondrocyte. The same changes were observed in group A. 5)The cartilage surface lost its smoothness during distraction, and this kind of changes were more severe when distraction increased. Conclusion The articular cartilage showed certain adaption to stimulation of distraction during low degree distractions. To greater distraction degrees some abnormality in metabolism of arthrodial cartilage may occure.