Intravenous Transplantation Of BMSCs Repaired The Inner Ear After Noise Exposure

Background:Noise trauma is given priority to with hearing loss of slowly progressive and Multiple systematic damage which is caused by long-term exposure to noise.The damage in hearing called Noise Induced Hearing Loss(NIHL),belongs to a kind of sensorineural deafness,the main pathophysiological mechanisms of NIHL are damage of hair cells,supporting cells and spiral ganglion cells.The regeneration of injury mammalian inner ear hair cells and spiral ganglion cells is limited.Treating sensorineural deafness in etiology will be a big challenge,but the replacement of stem cells transplantation therapy will be a break through.Objective:Noise could make the decrease of the hair cells and spiral ganglion cell or fiber.However,mammalian cochlea hair cells and spiral ganglion cells self-renewal limited,that make permanent hearing decline.In order to find an another effective tool for stem cell supply to the inner ear.,Systemic application of bone mesenchymal stem cells after noise-induced hearing loss in rats.Methods:1.Culture and label of the BMSCs :Establishing a stable system of SD rat BMSCs,and the BMSCs were marked with PKh26.2.The establishment of NIHL:Making noise induced hearing loss rat model by being exposed to 4000 Hz,120dBSpL narrow band white noise for 9h.3.The transplantation of BMSCs: 36 experimental rats were randomly divided into three group.A:non-NIHL+BMSCs,B:NIHL+non-BMSCs,C: NIHL+BMSC.The transplantation of BMSCs through the rats’ caudal vein.4.Cochlear tissue frozen section: Sacrificed 4 rats of group A and group B in6 th weeks after transplantation,taking the rat cochlea frozen section to evaluated the survival and differentiation of the transplanted cells by immunofluorescence staining of hair cells markers(Myosin VIIa,Math1)and spiral ganglion neuronsmarkers(Neurofilament-M,Map2)5.Cochlea basilar membrane streched preparation: In 2th weeks and 6 th weeks,choosing 4 cochleas in each group to make basilar membrane streched preparation,then observing the changes of the morphology and number of hair cells6.Cochlea HE staining: In 6th weeks,choosing 4 cochleas in each group to make cochlea axial paraffin section,HE stain for counting SGCs cell density.Results:1,the revival BMSCs could stable extend,and form a uniform long spindle,vortex pattern.The red fluorescence of Pkh26 can dye evenly distributed in the membrane surface of the BMSCs.2,In the group C,BMSCs could be found in the modiolus of cochlea,basement membrane and stria vascularis,and some label cells can express the spiral ganglion neurons markers and hair cell markers.Less red fluorescence were seen in the cochlea of group A、B.3,The damage of hair cells was mainly in the end of bottom back and the start of second back,and the hair cells loss is given priority to outer hair cellse.The damage of inner hair cells was the decline of succinate dehydrogenase activity.4,By the 2 week after cell transplantation,the number of hair cells have no obvious recovery,by the 6 week after cell transplantation,visible to the number of hair cells have a certain degree of recovery.5,Spiral ganglion cell density of group C was increased comparing with group B.Conclusion:1.the revival BMSCs could stable extend and efficiently marked with Pkh26.2.The intravenous transplantation of BMSCs can migrate,survive and engraft in cochlear,and differentiate into the cells expressing hair cells markers and spiral ganglion neurons markers.3.The transplanted BMSCs could recovery rat cochlea hair cells number and spiral ganglion cells number.