BSHXF-medicated serum combined with ADSCs regulates the TGF-β1/Smad pathway to repair oxidatively damaged NPCs and its component analysis

Lower back pain (LBP) is a common and frequent clinical condition, and intervertebral disc degeneration (IDD) is recognized as the leading cause of LBP, typically manifested by increased nucleus pulposus cell (NPC) senescence and death. In recent years, the treatment of IDD with stem cell injections has had great potential compared to surgical treatment. Combining the two may achieve better results, as BuShenHuoXueFang (BSHXF) is an herbal formula that improves the survival rate of transplanted stem cells and enhances their efficacy. We aimed to qualitatively and quantitatively analyze BSHXF-medicated serum and investigate the molecular mechanism of BSHXF-mediated serum in promoting the differentiation of adipose mesenchymal stem cells (ADSCs) into NPCs and delaying the senescence of NPCs by regulating the TGF-β1/Smad pathway. In this study, an ultrahigh-performance liquid chromatography-quadrupole-time-of-flight mass spectrometer (UPLC-Q-TOF-MS) was used to establish a method for the analysis of rat serum samples to track the active components in vivo; the oxidative damage model of NPCs was induced by T-BHP, and a Transwell chamber was used to construct a coculture system of ADSCs and NPCs. Flow cytometry was used to determine the cell cycle; SA-β-Gal staining was used to assess cell senescence; ELISA was used to detect IL-1β, IL-6 inflammatory factors, CXCL-1, CXCL-3, CXCL-10 chemokines, and TGF-β1 in the supernatants of ADSCs and NPCs. WB was used to detect COL2A1, COL1A1, and Aggrecan in ADSCs to assess the manifestation of NP differentiation in ADSCs, and the WB method was used to detect COL2A1, COL1A1, Aggrecan, p16, p21, p53, and p-p53 protein expression in NPCs to reflect the cellular senescence status and to detect TGF-β1, Smad2, Smad3, p- Smad2, and p- Smad3 protein expression in NPCs to reflect the pathway condition. We finally identified 70 blood components and their metabolites, including 38 prototypes, from the BSHXF-medicated serum. Compared with that in the nonmedicated serum group, the TGF-β1/Smad pathway was activated in the medicated serum group, ADSCs moved toward NPC characteristics, the number of NPCs in the S/G2M phase increased, the number of senescent NPCs decreased, IL-1β and IL-6 inflammatory factors in the Transwell decreased, CXCL-1, CXCL-3, and CXCL-10 chemokines decreased, and the expression of p16, p21, p53 and p-p53 proteins in NPCs was inhibited. By regulating the TGF-β1/Smad pathway, BSHXF-medicated serum promoted ADSCs to NPCs, effectively alleviated the cycle blockage of NPCs after oxidative damage, encouraged the growth and proliferation of NPCs, delayed the aging of NPCs, improved the deteriorating microenvironment around NPCs, and repaired oxidatively damaged NPCs. The combination of BSHXF or its compounds with ADSCs has great potential for the treatment of IDD in the future.