Neurotoxic Action of Aluminum Salts

Abstract

In the course of experiments involving the fractionation of herpes virus preparations by aluminum salts it was observed that rabbits which had received an intracerebral injection of certain fractions developed a syndrome indicative of a lesion of the central nervous system. The possibility of herpes encephalitis was excluded by the dissimilarity in symptoms and in cellular pathology. Nevertheless, several features of this syndrome, which had a uniformly fatal termination, were suggestive of a neurotropic virus disease, and a further investigation was made of its etiology.

It was found that the characteristic syndrome may be induced in rabbits, mice and monkeys by a single intracerebral injection of a small amount of an aluminum salt. Siem 1 and Dollken 2 reported observing neurologic symptoms in rabbits, cats and dogs which had received subcutaneous injections of aluminum in the form of sodium aluminum tartrate or lactate. They found lesions in the central nervous system of these animals, particularly nerve cell degeneration in the lower cranial nerves. Seibert and Wells 3 reported lesions in the central nervous system of one of a series of rabbits to which large amounts of aluminum or its salts had been administered. Scant attention has been paid to the neurotoxic action of aluminum salts and no instance of intracerebral administration of these salts has come to our attention.

When the proper dose of aluminum salt is given intracerebrally, the animal recovers uneventfully from the injection. The subsequent course is a febrile, except for rare elevations of temperature which appear to be irrelevant. After a lapse of 7 to 10 days in the rabbit, the first characteristic symptom appears. This consists in the disinclination of the animal to resume the normal posture when the hind quarters are twisted through 90 degrees about the longitudinal axis.