Inner ear spiral ganglion cell insult model by glutamate in newborn guinea pigs

AIM To study the neurotoxicity in newborn guinea pig spiral ganglion cell of glutamate by different doses and to establish an ideal glutamate dependent deaf model. METHODS Four groups of guinea pigs were first given glutamate by 0, 1, 2 and 4 g·kg -1 ·d -1 ip respectively for 7 days and then fed for another 35 days. Before they were sacrificed, PR and brainstem auditory evoked potential (BAEP) of guinea pigs were tested. The cochlear spiral ganglion was measured by Nissl stain method . RESULTS The mortality rate of the four groups was 0/10, 2/10, 4/10, 20/20 respectively. BAEP reaction threshold were: G0 group (43 5±3 4) dB,G1 group (43 8±9 4) dB and G2 group (67 3±23 3) dB respectively. The density rates of ganglion cells were (4345 7±241 4)·mm -2 , (4215 4± 295 2)·mm -2 and (1997 5±1019 8)·mm -2 respectively. The differences between G2 and other groups were significant, P0 01. CONCLUSION Glutamate treatment leads to dose dependent degeneration of cochlea spiral ganglion cells in newborn guinea pigs and 2 g·kg -1 ·d -1 , ip is an ideal dose to make a glutamate dependent deaf model.