Kobayashi M, Kawamura K, Honma M, Masuda H, Suzuki Y, Hasegawa H
Second Department of Pathology, Akita University School of Medicine, Akita, 1-1-1 Hondo, 010-8543, Japan.
Microvasc Res. 1999 May;57(3):258-72. doi: 10.1006/mvre.1999.2148.
To characterize the configuration of "tunnel capillaries" in myocytes, an ultrastructural three-dimensional (3-D) study was performed on pressure-overloaded rat hearts induced by 16-week constriction of the ascending aorta. The hearts showed high incidence (6.1 +/- 3.6%) of tunnel capillary formation. Eighty-two myocytes (26.4%) had tunnel capillaries in a cubic block of 120 x 656 x 446 micron3, which provided 1000 ultrathin serial sections. The cross-sectional area (925 +/- 226 micron2) of myocytes with tunnel capillaries was significantly larger than that of myocytes without tunnel capillaries (702 +/- 196 micron2) (P < 0.0001). There were three types of tunnel capillaries. Type I (13%) started from one intercellular capillary, ran across the myocyte, and then merged with other intercellular capillaries. Type II tunnel capillaries (87%) entered the myocyte from one intercellular capillary and ended within the myocyte. Type III tunnel capillaries were characterized by various combination of types I and II, forming a tunnel capillary network. Tunnel capillaries usually entered a myocyte at the place where the myocyte split or indented. Although some tunnel capillaries might be newly formed by angiogenesis, our 3-D study suggests that some of them are a deformation consequence of the myocardium remodeling in response to pressure overloading.
为了描述心肌细胞中“隧道毛细血管”的形态结构，我们对升主动脉缩窄16周诱导的压力超负荷大鼠心脏进行了超微结构三维（3-D）研究。这些心脏显示出较高的隧道毛细血管形成发生率（6.1±3.6%）。在一个120×656×446立方微米的立方体区域内，82个心肌细胞（26.4%）有隧道毛细血管，该区域提供了1000张超薄连续切片。有隧道毛细血管的心肌细胞的横截面积（925±226平方微米）显著大于没有隧道毛细血管的心肌细胞（702±196平方微米）（P<0.0001）。有三种类型的隧道毛细血管。I型（13%）从一个细胞间毛细血管开始，穿过心肌细胞，然后与其他细胞间毛细血管汇合。II型隧道毛细血管（87%）从一个细胞间毛细血管进入心肌细胞并在心肌细胞内终止。III型隧道毛细血管的特征是I型和II型的各种组合，形成一个隧道毛细血管网络。隧道毛细血管通常在心肌细胞分裂或凹陷的部位进入心肌细胞。虽然一些隧道毛细血管可能是通过血管生成新形成的，但我们的三维研究表明，其中一些是心肌对压力超负荷重塑的变形结果。
