Guinea Pig Specific Cytomegalovirus (GPCMV) was injected into the scala tympani (ST) of 24 guinea pigs, they were sacrificed on days 2, 4, 6 and 8 after the viral inoculation. The threshold of compound AP was measured on day 0 and on the days they were sacrificed. The histological investigation of their cochleae was also performed.
The compound AP threshold of seronegative animals elevated gradually, and it showed no reaction on day 8. While that of seropositive snimals kept its own level.
Exemination of the cochleae revealed hemorrhage and mild cell infiltration in the ST and in the lower part of the spiral ligament on day 4; moderate cell infiltration including macrophages and giant cell in the ST on day 6; and the typical cytomegalic inclusion cell, fusion cells and degeneration of the spiral ganglia and organs of Corti on day 8. The sequent elevation of the compound AP threshold seemed to correlate well with histological damages of the cochleae.