Studies on the mechanism of cadmium-induced toxic effects(Autoradiographic demonstration of cadmium unbound to metallothionein)

描述了一种新的放射自显影技术，用于证明组织切片中未与金属硫蛋白结合的痕量“游离镉”。这是通过使用[14C-1,4,5,8-萘酚]-1-(噻唑基)-2-萘酚(TAN)代替金属放射性同位素来实现的。在该方法中，组织切片用标记的 TAN 水溶液染色，然后将切片放入 2-丙醇中以除去任何未反应的 TAN。最后对净化后的切片进行通常的放射自显影程序。在由注射了稀释的乙酸镉水溶液的组织制备的切片中观察到覆盖有色区域的高浓度颗粒。这证明了根据组织中的化学形态区分镉的可行性。该技术可能会产生有关生物系统中镉毒性的更多信息。

A new autoradiographic technique for demonstrating trace amounts of "free cadmium" which remains unbound to metallothionein in a tissue section is described. This was realized by the use of [14C-1,4,5,8-naphthol]-1-(thiazolylazo)-2-naphthol (TAN) instead of a metal-radioisotope. In this method, tissue sections were stained with an aqueous solution of labeled TAN, and then the sections were placed in 2-propanol in order to remove any unreacted TAN. The decontaminated sections were finally subjected to the usual autoradiographic procedure.A high concentration of grains overlying coloured regions was observed in sections prepared from tissues injected with a diluted aqueous solution of cadmium acetate. This demonstrated the feasibility of the differential demonstration of cadmium according to its chemical forms in tissues. This technique may yield additional information as to the toxicity of cadmium in biological systems.