Bone marrow mesenchymal stem cells (BMSCs) expressing recombinant
IL-4 have the potential to remediate inflammatory diseases. We thus investigated whether BMSCs expressing exogenous
IL-4 could alleviate autoimmune
sensorineural hearing loss. BMSCs isolated from guinea pigs were transfected with recombinant lentivirus expressing
IL-4. A total of 33 animals were divided into three groups. Group A received scala tympani injection of IL-4-expressing BMSCs, and Group B received control vector-expressing BMSCs, and Group C received
phosphate-buffered saline. The distribution of implanted BMSCs in the inner ears was assessed by immunohistochemistry and fluorescence microscopy. Auditory brain-stem response (ABR) was monitored to evaluate the auditory changes. Following BMSCs
transplantation, the threshold levels of ABR wave III decreased in Groups A and B and significant differences were observed between these two groups (P < 0.05). Transplanted BMSCs distributed in the scala tympani and scala vestibuli. In some ears with
hearing loss, there was a decrease in the number of spiral ganglion cells and varying degrees of
endolymphatic hydrops or floccule. Following
transplantation, the lentivirus-infected BMSCs migrated to the inner ear and produced
IL-4. Our results demonstrate that, upon
transplantation, BMSCs and BMSCs expressing recombinant
IL-4 have the ability to remediate the inflammatory injury in autoimmune
inner ear diseases.