QUANTIFICATION OF THE STRIA VASCULARIS AND STRIAL CAPILLARY AREAS IN QUIET-REARED YOUNG AND AGED GERBILS

The area of the stria vascularis (StV) and of StV capillaries was meas ured in radial sections from regions corresponding to 0.5, 2, 4, 10, 2 0 and 40 kHz. In young gerbils, StV area ranged from 3700 to 8500 mu m (2) and that of individual StV capillaries from 70 to 110 mu m(2). The maximal StV area as well as the largest number of capillaries occurre d at the 20 kHz region. In quiet-aged gerbils, the StV area also varie d with frequency and was 28-67% smaller than corresponding measures in young gerbils. The decrease in StV area was statistically significant at all but the 2 and 4 kHz regions. The area of individual StV capill aries declined also (8-29%) with age even when the StV area remained n ear normal. Reductions in capillary area were statistically significan t at the 2, 20 and 40 kHz regions. The large variance in StV radial ar ea among aged gerbils reflects the patchy nature of strial degeneratio n previously observed in this species. The data agree with those of ou r previous studies and indicate alterations in StV capillaries are a p rimary cause of presbyacusis in the gerbil. (C) 1997 Elsevier Science B.V.