Roxadustat pre-conditioning and cyclic uniaxial stretching improve tenogenic differentiation potential of human adipose derived mesenchymal stromal cells

Tendon injuries represent a significant challenge to treat owing to their limited intrinsic reparative capacity. The use of mesenchymal stem cells (MSC) offers promising alternative therapeutic option to augments tendon repair. It is hypothesised that the activation of hypoxia inducible factor-1 alpha (HIF-1 alpha), could facilitate the tendon repair process by promoting the proliferation and tenogenic differentiation of MSCs. To demonstrate this, a study was conducted incorporating the use of Roxadustat, a specific hypoxia mimetic mediator and cyclic uniaxial stretching at a frequency of 1 Hz and 8 % strain on adipose derived-mesenchymal stromal cells (ADMSCs). Methods: Cellular morphology, proliferation rate, tenogenic protein and gene expression levels from 8 different treatment groups were compared. These groups include untreated ADMSCs (Control), Roxadustat preconditioned ADMSCs (ROX), ADMSCs subjected CAY10585 treatment only (CAY), Roxadustat pre-conditioned ADMSCs with CAY10585 inhibition (ROX+CAY), ADMSCs subjected to uniaxial stretching only (S), Roxadustat pre-conditioned ADMSCs with uniaxial stretching (ROX+S), ADMSCs subjected CAY10585 with uniaxial stretching (CAY+S) and primary tenocytes (Tenocytes). Results: ROX+S group exhibited the highest expression of HIF-1 alpha and demonstrated a significant up-regulation of collagen I and III expressions, increasing by 4.9 and 5.6-fold compared to ROX group, respectively. There is a significant increase of SCX, TNC, TNMD, COLI and COLIII expression in this combination treatment group; (SCX= 9.9, TNC= 12.6, TNMD= 7.0, COLI= 8.0 and COLIII= 10.0-fold). Conversely, the expression of the markers markedly reduced with HIF-1 alpha inhibitor CAY10585. However, uniaxial stretching effectively counteracted the inhibitory effects of CAY10585 in the CAY+ S group, resulting in a 3.9-fold increase in SCX expression compared to CAY treatment alone. Conclusion: HIF-1 alpha accumulation promotes superior tenogenic differentiation of ADMSCs, suggesting that the combination of Roxadustat and cyclic uniaxial stretching may be a potential therapeutic mediator in tendon repair strategies.