Role of Endogenous Bone Marrow Stem Cells Mobilization in Repair of Damaged Inner Ear in Rats

BACKGROUND AND OBJECTIVES The utilization of the stem cells is widely used in the last few years in different fields of medicine, either by external transplantation or endogenous mobilization, most of these studies still experimental on animals; few were tried on human as in the spinal cord injury or myocardial infarction. As regard its use in the inner ear, stem cell transplantation was examined in many previous studies, while the mobilization idea is a new method to be experimented in inner ear hair cell regeneration. The present work assessed the possibility of mobilizing endogenous bone marrow derived stem cells (SCs) in rats using granulocyte colony stimulating factor (G-CSF) to induce regeneration and repair to experimentally damaged inner ear hair cells by Amikacin injection. METHODS The study included thirty adult Sprague Dawley male rats. Experimental induction of inner ear damage was done by repeated intratympanic injection of amikacin sulfate. Mobilization of bone marrow SCs was provoked by subcutaneous injection of GCSF. Cochlear integrity, induction of hearing loss and functional recovery of sensory hearing loss were assessed using Distortion Product Otoacoustic Emission (DPOAEs). The morphological alteration and recovery of the organ of Corti was assessed histologically using the light and scanning electron microscopes. RESULTS After six month duration, there was improvement in 50% of the sensorineural DPOAE results. Functional recovery coincided with the repair of structural components of organ of Corti. CONCLUSIONS SCs mobilization by G-CSF is a promising alternative method for replacement therapy in sensorineural hearing loss.