Bleomycin Induces Fibrotic Transformation of Bone Marrow Stromal Cells to Treat Height Loss of Intervertebral Disc Through the TGFβR1/Smad2/3 Pathway
Background: Lower back pain is often accredited to loss of intervertebral disc (IVD) height and compromised spine stability as a result of intervertebral disc degeneration (IVDD). We aim to locally use Bleomycin to induce the fibrotic transformation of bone marrow stromal cells (BMSCs) as a means to induce reparative fibrosis to slow down the height loss.Methods: IVD from patients were gathered for histological examination. The expression of transforming growth factor beta 1 (TGF-β) signaling
... (TGF-β) signaling pathway was determined by qPCR and western blotting. Nucleus pulposus (NP) cells, annulus fibrosus (AF) cells and the Rats' bone marrow stromal cells (BMSC)were cultured and their responsiveness to Bleomycin was evaluated by Cell Counting Kit-8, comet assay, transwell migration and wound healing assays. Rat IVDD models were created by puncture, rescued by Bleomycin injection and the effectiveness was evaluated by images (X-ray and MRI) and atomic force microscope.Results: Histological examination showed increased levels of pro-fibrotic markers in IVDD tissues from patients. AF cells and BMSC cells was induced to adopt to a pro-fibrotic phenotype with increased expression fibrotic markers Col1a1, Col3a1, FSP1. The pro-fibrotic effect of Bleomycin on AF cells and BMSCs was in part due to the activation of the TGFβ-TGFβR1-SMAD2/3 signaling pathway. Pharmacological inhibition or gene knock-down of TGFβR1 could mitigate the pro-fibrotic effects. Conclusion: Locally injection of Bleomycin in rats' IVD induced rapid fibrosis and maintained its height through TGFβ-TGFβR1-SMAD2/3 signaling pathway.