The Correlation Study Of STAT3 And Regeneration Of Lateral Line Hair Cells In Zebrafish Larvae

[Background]Cisplatin is a widely used anti-tumor drug in clinical practice with cytotoxicity and ototoxicity,which can cause irreversible sensorineural deafness.Currently,there is no drug that can effectively prevent or treat hearing impairment caused by hair cell damage or loss.Previous studies suggest that Cisplatin can directly damage cochlear hair cells,as well as vascular striate cells and spiral ganglion neurons.Hair cell regeneration is still a difficult and hot topic in the field of otology and audiology.The process of hair cell development and regeneration is regulated by various molecular mechanisms,including Atohl,Wnt,Notch,FGF,Shh,etc.STAT3,an important part of the JAK-STAT signaling pathway,is expressed in many cells and tissues.STAT3 plays a role in regulating cell growth,differentiation,apoptosis,angiogenesis,metabolism,and immune response.However,the role of STAT3 in hair cell regeneration has not been elucidated.Zebrafish and human genes are highly homologous,and both inner ear hair cells and Lateral line hair cells can regenerate spontaneously.The zebrafish lateral line system has the characteristics of simple structure,easy operation and intuitive observation.It is an ideal model for studying hair cell damage and regeneration.Accordingly,we used cisplatin to establish a zebrafish larvae model for studying the injury and regeneration of lateral line hair cells.Furthermore,the correlation of STAT3 and regeneration of lateral line hair cells in zebrafish larvae were studied.[objective]Establish a zebrafish larvae model for studying the injury and regeneration of lateral line hair cells;Analyzed the correlation of STAT3 and regeneration of lateral line hair cells in zebrafish larvae.[Methodl](1)The 5 days post fertilization(dpf)zebrafish larvae were treated with 50μmol/L cisplatin for 24h.We labeled the lateral line hair cells with YO-PRO-1 and FM1-43FX and observed the damaged and regenerated hair cells by microscope.(2)We used zebrafish whole-mount in situ hybridization to detect the expression of STAT3 gene in lateral hair cell regeneration.(3)We used APTSTAT3-9,a STAT3 specific inhibitor,to treat the cisplatin injured zebrafish larvae,and observed the changes of regenerative lateral line hair cells.[Result](1)After treating the 5dpf zebrafish larvae with 50μmol/L cisplatin for 24h,the lateral line hair cells marked by YO-PRO-1 completely disappeared.At 6h,12h,24h and 48h after the removal of cisplatin,the hair cells marked by FM1-43FX increased significantly with time.(2)STAT3 gene is expressed in the neuromasts at 5 dpf zebrafish larvae.Compared with the control group,the expression was significantly increased at 6h after removal of cisplatin.However,the expression of STAT3 at 12h after removal of cisplatin was lower than the control groupP reaching the"trough".The expression of STAT3 was increased in a gradient at 24h and 48h after removal of cisplatin.The expression of STAT3 gene at 48h was similar to the control group.(3)The higher the concentration of APTSTAT3-9R,the less the number of regenerative lateral line hair cells and the slower the regeneration rate of zebrafish larvae after cisplatin treatment.[Conclusionl](1)Treating the 5dpf zebrafish larvae with 50μmol/L cisplatin for 24h can completely damage lateral line hair cells.Hair cells have the ability to spontaneously regenerate.It is feasible to establish a zebrafish larvae model studying the injury and regeneration of lateral line hair cells using 5dpf zebrafish.(2)STAT3 possibly involved in functional maintenance and self-renewal of lateral line hair cells in normal zebrafish.(3)STAT3 plays a role in maintaining the dynamic balance of the number of lateral line hair cells in zebrafish.(4)STAT3 possibly plays a positive role in the regeneration of lateral hair cells in zebrafish larvae.