AUDITORY BRAIN-STEM RESPONSES IN A RHESUS MACAQUE MODEL OF NEURO-AIDS

Nine rhesus macaques (Macaca mulatta) were inoculated with a combinati on of two passaged strains of SIVmac (R71 and 17E), both of which are known to be neurovirulent. Auditory brainstem responses (ABRs) were re corded at regular intervals from these animals both before and after i noculation. Increases in ABR peak and interpeak latency were observed corresponding to progression of SIV disease. Post-inoculation increase s in latency were observed for all five peaks of the ABR and for inter peak intervals I-V and III-V, The largest increases in latency were as sociated with end-stage disease. Within 14 weeks of inoculation, all b ut two animals developed end-stage simian AIDS and were euthanized. Hi stopathological examination revealed multifocal lesions in the cerebra l gray and white matter as well as in the auditory structures of the b rainstem. In most animals, ABR changes were accompanied by evidence of underlying neuropathology. However, cases of severe neuropathology wi th no ABR abnormalities and vice versa were also noted. Though in a mu ch shorter time frame, SIVmac R71/17E produced both physiological and histopathological abnormalities similar to those associated with HIV d isease in humans. These results further support the SIVmac R71/17E inf ected rhesus macaque as an animal model of HIV related neurological di sease in humans.