Objective To study the ultrastructural features of myocytes in uterine junctional zone (JZ).Methods From August 2010 to August 2013,there were 16 pre-menopause patients who suffered from cervical neoplasm to be performed hysterectomy.Samples of JZ and outer myometrium (OM) of hysterectomy specimens were collected.There were 8 specimens from the proliferative-phase and 8 specimens from the secretory-phase of endometrium.Ultrastructural features of JZ and OM were examined by using transmission electron microscopy and the related indices of myocytes were compared by using Student's t test.Results At JZ,there were more cytoplasmic process in the myocytes.The myocytes of JZ exhibited significant difference compared with those of OM.Firstly,the contractile structural components,such as the dense patches,dense bodies and the myofilaments were less abundant.In contrast,the perinuclear cell organelles were more distinct.The mitochondria,endoplasmic reticulum and Golgi apparatus were more prominent,denoting active protein synthesis.Secondly,the mean diameter of cell and nuclei demonstrated cyclic change.In proliferative phase of endometrium,the cell diameters of JZ and OM were (4.70_±0.52) and (4.69± 1.20) μm,respectively,which there were no significant difference(P=0.987).While in secretory phase,the cell diameters of JZ and OM were (3.75±0.36) and (4.92±0.51) μm,which there were significant difference (P=0.006).In proliferative phase,the nuclei diameters of JZ and OM were (3.24±0.41) and (2.90±0.62) μm,and in secretory phase,the nuclei diameters of JZ and OM were (2.44±0.27) and (2.92±0.44) μm.There were no significantly different in both phases (P=0.374,P=0.097).The diameters of cell and nuclei had cyclical changes (P ＜ 0.05).However,the cyclical changes were absent in OM (P＞ 0.05).Thirdly,the myofilaments/cytoplasm ratio of JZ in proliferative and secretory phases were 0.27±0.04 and 0.34±0.03,which were significantly less than those of OM in respective phases (0.49±0.03and 0.54±0.03;P=0.000,P=0.000).The myofilaments/cytoplasm ratio exhibited cyclical changes in JZ (P=0.029),but in OM,the cyclical changes were absent (P=0.083).Conclusions Compared with OM,ultrastructures associated with synthetic organelles are prominent,whereas the contractile organelles are reduced.And there are the cyclical changes in ultrastructural characteristics.The ultrastructural features of JZ are the basis of its physiology.%目的 探讨子宫结合带区(JZ)肌细胞的超微结构特点.方法 收集2010年8月至2013年8月在首都医科大学附属北京妇产医院妇科微创中心因子宫颈病变行子宫全切除术的绝经前患者共16例,其中增殖期及分泌期各8例.子宫切除后取JZ组织及子宫外周肌层组织进行电镜标本的制作,与外周肌层肌细胞相对比,电镜观察JZ肌细胞的超微结构,并对JZ肌细胞和细胞核的大小、细胞内肌丝/细胞质面积的比值及其周期性变化进行定量分析.结果 (1)JZ肌细胞的超微结构:与外周肌层肌细胞相比,JZ肌细胞的胞突多;JZ肌细胞内与细胞合成功能相关的细胞器成分,如线粒体、高尔基体、内质网等明显增多,而与细胞收缩功能相关的成分如密体及密斑等减少.(2)JZ肌细胞和细胞核的大小及其周期性变化:增殖期JZ肌细胞和外周肌层肌细胞的直径分别为(4.70±0.52)、(4.69±1.20) μm,两者比较,差异无统计学意义(P=0.987);分泌期JZ肌细胞和外周肌层肌细胞的直径分别为(3.75±0.36)、(4.92±0.51) μm,两者比较,差异有统计学意义(P=0.006).增殖期JZ肌细胞和外周肌层肌细胞核的直径分别为(3.24±0.41)、(2.90±0.62)μm,分泌期JZ肌细胞和外周肌层肌细胞核的直径分别为(2.44±0.27)、(2.92_±0.44) μm,两者分别比较,差异均无统计学意义(P=0.374,P=0.097).JZ肌细胞及细胞核的大小均随月经周期而发生明显的周期性变化(P＜0.05),而外周肌层肌细胞及细胞核的大小随月经周期均未发生明显的周期性变化(P＞0.05).(3)JZ肌细胞内肌丝/细胞质面积的比值及其周期性变化:增殖期、分泌期JZ肌细胞内肌丝/细胞质面积的比值分别为0.27±0.04、0.34±0.03,均显著低于相应期别的外周肌层肌细胞的0.49±0.03、0.54±0.03 (P=0.000,P=0.000).JZ肌细胞内肌丝/细胞质面积的比值也随月经周期而发生明显的周期性变化(P=0.029),而外周肌层肌细胞内肌丝/细胞质面积的比值随月经周期未发生明显的周期性变化(P=0.083).结论 与外周肌层肌细胞相比,JZ肌细胞中与合成功能相关的细胞器成分增加,而与收缩功能相关的细胞器成分减少;且超微结构特点在月经周期的不同时相呈现明显的周期性变化,这是其生理功能的结构基础.
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