Sotrel A, Lorenzo A V
Department of Pathology, Beth Israel Hospital, Boston, MA 02215.
J Neuropathol Exp Neurol. 1989 Jul;48(4):462-82. doi: 10.1097/00005072-198907000-00007.
Approximately 20% of preterm rabbit pups develop spontaneous germinal matrix hemorrhages (GMH). To understand better the pathogenesis of GMH we studied the ultrastructure of germinal matrix (GM) blood vessels in rabbits delivered at gestational day 28. Regardless of luminal size, the walls of most GM vessels had the structural characteristics associated with a blood-brain barrier (BBB) and consisted of endothelial cells and pericytes, surrounded by GM cell processes. Endothelial cells ranged from voluminous to attenuated, with some cells containing intracytoplasmic, membrane-bound vacuoles, and luminal as well as abluminal cytoplasmic projections. Some short interendothelial junctions had no puncta adherentia, whereas long ones often possessed intermittent pores. In two animals with GMH, intact endothelial cells were separated by narrow and wide gaps filled with luminal contents that occasionally extended beyond the interendothelial opening. The basal lamina (BL) was ill-defined, thin, often discontinuous and of low electron density. Smooth muscle cells and collagen were not present, which precluded any classification into arteries, capillaries and veins. Germinal matrix cell processes lacking both micro- and intermediate filaments were haphazardly disposed around the blood vessel walls in place of astrocytic endplates. Recent reports indicate that an astrocytic environment may be necessary for the development of the interendothelial tight junctions and BL. The presence of "glial foot" processes that lack ultrastructural characteristics of mature astrocytes suggests that interendothelial junctions and basal laminae in the vessels of the ganglionic eminence may not have the necessary structural and functional potential to withstand the transmural pressures or the pathophysiological influence of hypertension, hyperosmolarity, sepsis, and other factors known to open the BBB and to contribute to GMH.
约20%的早产兔幼崽会发生自发性生发基质出血（GMH）。为了更好地理解GMH的发病机制，我们研究了妊娠28天时分娩的兔子生发基质（GM）血管的超微结构。无论管腔大小如何，大多数GM血管壁都具有与血脑屏障（BBB）相关的结构特征，由内皮细胞和周细胞组成，周围环绕着GM细胞突起。内皮细胞从体积大到变细不等，一些细胞含有胞质内、膜结合的空泡，以及腔内和腔外的胞质突起。一些短的内皮间连接没有粘着斑，而长的连接常常有间断的孔隙。在两只发生GMH的动物中，完整的内皮细胞被狭窄和宽阔的间隙隔开，间隙中充满了腔内物质，这些物质偶尔会延伸到内皮间开口之外。基膜（BL）不清晰、薄、常常不连续且电子密度低。不存在平滑肌细胞和胶原，这使得无法将其归类为动脉、毛细血管和静脉。缺乏微丝和中间丝的生发基质细胞突起杂乱地分布在血管壁周围，取代了星形胶质细胞终板。最近的报告表明，星形胶质细胞环境可能是内皮间紧密连接和BL发育所必需的。缺乏成熟星形胶质细胞超微结构特征的“胶质足”突起的存在表明，神经节隆起血管中的内皮间连接和基膜可能没有必要的结构和功能潜力来承受跨壁压力或高血压、高渗、败血症和其他已知会打开BBB并导致GMH的病理生理影响。
