Expressions of caspase-3 protein in spiral ganglion cell following guinea pigs cochlear damage caused by shock wave

Objective To investigate the expressions of caspase-3 protein in spiral ganglion cell (SGC)and its correlation with auditory threshold shift following guinea pigs cochlear damage caused by air blast,to further study the mechanism of blast trauma causing deafness. Methods Twenty guinea pigs were randomly divided into control group and experimental group. Experimental group: by using air blast device to cause guinea pigs cochlear damage. Auditory threshold was tested before and after experiment for all the animals. Animals were killed and cochleas were taken for study after 12 hours. Apoptosis of SGC was observed through TEM, TUNEL and expression of caspase-3 was tested by immunohistochemical method. Results Test of auditory threshold: the AB threshold of experimental group were apparently higher than control groups, auditory function of experimental group was injured severely. The ultrastructural changes of SGC: cellular organs of SGC were damaged severely in experimental group. Nucleoli were distorted, mitochondria swelled, the number of rough ebdoplasnic reticulum (REM) was increased. In control groups, the nucleoli of SGC weren't distorted; the structure of mitochondria was normal. TUNEL showed that apoptosis of SGC was noted in experimental group, the apoptosis cells in basal turn were more than apical turn. No apoptosis was detected in control groups. Caspase-3 masculine reaction staining only appeared in experimental group samples. Conclusion Cochlear damage caused by air blast could induce the apoptosis of spiral ganglion cell and increase expression of caspase-3 in guinea pigs.