Regenerative Stem Cell Therapy with Umbilical Cord Mesenchymal Stromal Cells in Deaf Animal Model

Abstract

Objectives: This study was performed to confirm the effect of transplantation of human umbilical cord blood mesenchymal stem cells (UCB-MSCs) on hearing restoration in deaf animal model. Methods: UCB was collected from pregnant women after obtaining consent, and mesenchymal stem cells (MSCs) were extracted. We established deaf animal model and transplanted UCB-MSCs through the brachial vein of the guinea pigs. The animals were divided into 4 groups: animals with normal hearing, animals with sensorineural hearing loss (SNHL), animals with SNHL and injected with saline, and animals with SNHL and transplanted with UCB-MSCs. Hearing tests were conducted at 1, 3, and 5 weeks, and the results were compared by grading auditory brainstem response (ABR) recordings and distortion product otoacoustic emissions (DPOAEs) for each treatment. Lastly, cochlear pathological features were examined. Results: In SNHL group, decreased DPOAEs and increased ABR threshold were noted. And ABR hearing thresholds were unconverted and were similar to those observed in deafness. The transplanted UCB-MSC group showed a significant improvement in hearing threshold (40 dB). Examination of the SNHL animals’ cochlear morphological features demonstrated a noticeable lack of spiral ganglion cells and also showed degenerated outer hair cells. However, the transplanted UCB-MSCs showed an increase in spiral ganglion and hair cells. Conclusions: Intravenous transplantation of UCB-MSCs can enhance hearing thresholds, and regenerate inner ear hair cells and spiral ganglion neurons (SGNs).