Hypoxia enhances tenocyte differentiation of adipose‐derived mesenchymal stem cells by inducing hypoxia‐inducible factor‐1α in a co‐culture system

Objectives Tissue engineering is a promising approach for repair of tendon injuries. Adipose‐derived mesenchymal stem cells ( ADMSC s) have gained increasing research interest for their potential in improving healing and regeneration of injured tendons. The present study aimed to investigate effects of O 2 tension and potential signalling pathways on AMDSC differentiation into tenocytes, in an indirect co‐culture system. Materials and methods Human ADMSC s were co‐cultured under normoxia (20% O 2 ) and also under hypoxia (2% O 2 ). Tenocyte differentiation of AMDSC s and expression of hypoxia‐inducible factor‐1 ( HIF ‐1α) were analysed by reverse transcription‐ PCR , Western blotting and immunohistochemistry. Furthermore, HIF ‐1α inhibitor and inducer ( FG ‐4592) effects on differentiation of AMDSC s were studied using qPCR , immunofluorescence and Western blotting. Results Indirect co‐culture with tenocytes increased differentiation of ADMSC s into tenocytes; furthermore, hypoxia further enhanced tenocyte differentiation of AMDSC s, accompanied by increased expression of HIF ‐1α. HIF ‐1α inhibitor attenuated effects of hypoxia on differentiation of ADMSC s; in contrast, FG ‐4592 increased differentiation of ADMSC s under both hypoxia and normoxia. Conclusions Taken together, we found that growing ADMSC s under hypoxia, or activating expression of HIF ‐1α to be important in differentiation of ADMSC s, which provides a foundation for application of ADMSC s in vivo for tendon regeneration.