Rassat J, Robenek H, Themann H
Exp Pathol. 1982;22(2):103-12. doi: 10.1016/s0232-1513(82)80031-5.
The effect of beta-pyridylcarbinol on mice was investigated in long-term studies (21 days, daily dose of 0.1 mg) making use of thin-sectioning and freeze-fracture techniques. Thin sectioning merely revealed only subtle pathological changes including dilatation of the intercellular space and foundation of hepatocytic vacuoles. Only upon investigation using freeze-fracture was it possible to demonstrate more profound alterations, primarily involving the cell contacts, i.e. the gap and tight junctions. The organized structure of the tight junctions appeared dissipated. The meshwork was disorganized in some cases and reduced in size. Large, proliferative tight junctional maculae were frequently observed on the plasmalemma. In some cases the gap junctions had lost their round to oval shape and had increased in size to form large plaques protruding at numerous points. Moreover, even the bile canaliculi, which presented no pathological alterations on ultrathin section, exhibited damage as seen in freeze-fracture preparations. The lumen was uneven in contour and processes were visible extending into the adjacent cytoplasm. The present investigation shows that hepatocytic damage primarily affecting the membranes was first made evident using freeze-fracture technique. The issue is addressed as to the extent to which freeze-fracture technique should be employed in routine investigations of pharmaceuticals.
利用薄切片和冷冻断裂技术，在长期研究（21天，每日剂量0.1毫克）中研究了β-吡啶甲醇对小鼠的影响。薄切片仅显示出细微的病理变化，包括细胞间隙扩张和肝细胞空泡形成。只有通过冷冻断裂技术进行研究，才有可能证明更深刻的改变，主要涉及细胞连接，即缝隙连接和紧密连接。紧密连接的组织结构似乎消散了。在某些情况下，网络结构紊乱且尺寸减小。在质膜上经常观察到大型、增殖性的紧密连接斑。在某些情况下，缝隙连接失去了圆形到椭圆形的形状，并且尺寸增大，形成了在许多点突出的大斑块。此外，即使在超薄切片上没有显示出病理变化的胆小管，在冷冻断裂标本中也表现出损伤。管腔轮廓不均匀，可见延伸到相邻细胞质中的突起。本研究表明，主要影响细胞膜的肝细胞损伤首先通过冷冻断裂技术得以显现。探讨了在药物常规研究中应在何种程度上采用冷冻断裂技术这一问题。
