The distribution and localization of 127m tellurium in normal and pathological nervous tissues of young and adult rats.

An equal amount (per weight) of 127m tellurium (Te) was injected IP into weanling and adult rats, some intoxicated with a diet containing Te, others not. The young intoxicated rats presented a segmental demyelination of the sciatic nerve and paralysis of the hind limbs; the adult intoxicated rats did not. Quantitation of 127m Te in nervous and other tissues was done with a gamma counter. Correlative morphological examination of the nervous tissues was done with light and electron microscopy. This study shows that Te crosses the vascular wall without injuring endothelial cells and invades the surrounding sciatic nerve parenchyma following administration of 127m Te to a weanling or adult rat. However, Te damages the endothelium, crosses the vascular wall of endo and perineurial vessels in weanling rats, causes a perivascular oedema, cytoplasmic anomalies in the Schwann cells, destruction of myelin and apparently invades axones--according to autoradiographic studies--following the administration of 127m Te plus the Te-diet. It is concluded that Te penetrates more quickly and in larger amounts the walls of blood vessels in the sciatic nerve of weanling rats intoxicated with Te, than the same nerve in the other weanling and adults rats. Te in the amounts indicated here penetrates the parenchyma of the CNS but apparently does not cause injury.