INVIVO AND INVITRO STUDY OF AN AGING-RELATED NEURON CYTOPLASMIC-BINDING ANTIBODY IN MALE FISCHER RATS

Fischer 344 male rats showed a low average level (less than ++) of in vivo as well as in vitro neuron binding antibody at 3, 15, and 26 months. However, a significant increase with age in average intensity of binding was observed with both the in vivo and the in vitro conditions. If a criterion of ++ is used as an antibody binding level likely to have biological consequences, the percent of in vivo cases showing foci of ++ or greater intensity also rises with age from 20 to 80%; a criterion of +++ gives an in vivo rise with age of only from 10 to 20%. The in vitro incidence with the ++ criterion is already 80% at three months and rises to 90%; with the +++ criterion the incidence with age rises from 20 to 80%. No evidence was obtained to support the concept that there is a weakening of the blood-brain-barrier in 26 month rats either by the systemic injection of trypan blue or by a comparison of intensity of antibody binding between extra- and intra-barrier neurons.