Changes of Serum Levels of Caspase-3 after Trauma and Ototoxic Damage of the Cochlea in Rabbits: An in vivo Study

Background: Caspase-3 is one of the most important enzymes for the regulation of apoptosis. Aims and Objectives: Aim of our study was to examine the changes in serum levels of this factor during apoptotic phenomena in the cochlea, caused by traumatic or ototoxic causes. Materials and Methods: A cohort of 24 rabbits was studied for this purpose for 31 days. Eight animals were implanted with a cochlear implant electrode (group A), 8 were treated with intramuscular amikacin for 14 days (group B) and another 8 were the control group (group C). In all groups DPOAEs and serum levels of caspase-3 were tested every second day. Results: Serum levels of caspase-3 rise immediately after implantation, while a 3-day latency in levels was seen in group B. Caspase-3-levels in both groups remained elevated until the 31st day of the experiment. Levels of caspase-3 showed a moderate negative correlation with DPAOE amplitudes. Conclusion: Caspase-3 rises after traumatic and ototoxic causes and moderately correlates with cochlear outer hair cell function in rabbits. Therefore, serum caspase-3 levels should be tested as a surrogate marker of structural integrity of the cochlea after trauma or administration of ototoxic drugs in humans as well.