[Protein concentration of perilymph in guinea pigs after noise exposure]

The protein concentration in the perilymph of noise-exposed guinea pigs was investigated using a micromethod described previously. The animals were exposed to wide band noise at 140 dB for one hour unilaterally in a closed acoustic system. Perilymph was obtained after exposure at different intervals: immediately, 6 or 24 hours later. From animals exposed to noise, it is particularly more difficult to obtain perilymph without blood contamination than from normal ones. Even post mortem, it is difficult to obtain samples without blood contamination and without hemolysis, particularly from the scala tympani. Therefore, some animals were perfused intra-arterially with Ringer solution or with Infukoll M 40 before decapitation. After exposure to noise only a small increase in protein concentration of the perilymph can be detected in the noise-exposed ears of animals perfused intra-arterially. The difference in concentration is most distinct in samples extracted 6 hours after noise exposure had ceased. No reliable clue to the source of this protein could be obtained from these investigations.