[Damage to cochleae in newborn guinea pigs by 80dB white noise]

Two groups of guinea pigs (the newborn and the adult) were exposed to 80dB SPL white noise for 72 hours. The effects were observed with E CochG, surface preparation, scanning electron microscopy and histochemical techniques. The results showed that: 1. the response threshold of the newborn was elevated after exposure; 2. the rate of OHC loss was higher in cochleas of the newborn than those of the adult; 3. OHC damage was mainly found in the fourth turn of cochlea of the newborn; 4. the LDH activity decreased in the newborn. It seems that the white noise could damage the hair cell function and structure in the newborn guinea pigs which are more susceptible to noise than the adult ones. The different susceptibility might be related to the degree of development and maturity of the cochleas.