THE EFFECT OF HYPERVITAMINOSIS A ON EMBRYONIC LIMB-BONES CULTIVATED INVITRO
THE EFFECT OF HYPERVITAMINOSIS A ON EMBRYONIC LIMB-BONES CULTIVATED INVITRO
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DOI：
10.1113/jphysiol.1952.sp004708
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发表时间：
1952-01-01
影响因子：
5.5
通讯作者：
MELLANBY, E
中科院分区：
文献类型：
--
作者：
FELL, HB;MELLANBY, E
对幼年动物的实验表明（Mellanby，1938，1939，1944，1947），维生素A通过控制骨膜骨中成骨细胞和破骨细胞的位置及其活动强度，决定某些骨的形状和质地。维生素的缺乏和过量都会引起骨骼的严重变化，尽管维生素的作用方式尚不清楚。几年前，人们开发了一种体外培养早期骨残基的方法（Fell & Robison，1929; Fell，1951）;外植体在体外以令人惊讶的正常方式生长并继续分化。Mellanby（1944）认为，这种骨培养可用于研究维生素A对骨骼组织的作用，特别是确定这种作用是否是直接作用。在体外培养有组织的组织的方法，由于它提供的实验条件大大简化，可能是动物实验的一种有价值的辅助手段。在体外，没有血管或神经系统，其他器官的影响完全消除;因此，体外化学制剂产生的任何影响都必须是由于其对组织的直接作用。此外，实验条件可以随意广泛变化，并且在组织培养中比在体内更容易控制;该技术具有进一步的优点，即可以在需要时在显微镜下观察活外植体。因此，决定进行实验，研究维生素A过多对通过钟表玻璃法体外培养的胚胎长骨的影响。在活的动物中，维生素A过多使长骨脆弱，以致有时会发生自发性骨折。这经常在喂食含有过量维生素A的饮食的幼鼠中观察到
Experiments on young animals have shown (Mellanby, 1938, 1939, 1944, 1947) that vitamin A determines the shape and texture of certainbones by controlling the position of the osteoblasts and osteoclasts of periosteal bone and the intensity of their activity. Both deficiency and excesof the vitamin cause severe changes in the skeleton, though the way in whichthe vitamin acts remains obscure.Some years agoa method was developed for cultivating early bone rudi-ments in vitro (Fell & Robison, 1929; Fell, 1951); the explants grew and con-tinued to differentiate in vitro in a surprisingly normal way. It occurred to Mellanby (1944) thatsuch bone cultures might be used to study the action of vitamin A on skeletal tissue and especially to decide whether the action was a direct one. The method of cultivating organized tissues in vitro may be a valuable adjunct to animal experiments because of the great simplification of experimental conditions which it provides. In vitro there are no vascular or nervous systems, and the influence of other organs is completely eliminated; thus any effect produced by a chemical agent in vitro must be due to its direct action on the tissue. Also the experimental conditions can be widely varied at will and are more easily controlled in a tissue culture than in the body; the technique has the further advantage that the living explants can be observed under the microscope whenever desired. It was therefore decided to undertake experiments on the effects of hypervitaminosis A on embryonic long bones cultivated in vitro by the watch-glass method. In the living animal, hypervitaminosis A renders the long bones fragile, so that they sometimes suffer spontaneous fracture. This has often been observed in young rats fed on a diet containing an excessive quantity of vitamin A