[Bushen Huoxue Decoction regulates ADSCs-Exos to affect nucleus pulposus cell apoptosis and ERK signaling pathway in intervertebral disc degeneration].

This study aims to investigate the effects of Bushen Huoxue Decoction regulating adipose-derived stem cells(ADSCs)-exosomes(Exos) on the apoptosis of intervertebral disc nucleus pulposus cells(NPCs) and extracellular signal-regulated kinase(ERK) signaling pathway. Tert-butyl hydrogen peroxide(TBHP)-induced NPCs were divided into control, model, drug-containing serum, blank Exos, normal serum Exos, and drug-containing serum Exos groups. Cell viability and proliferation were examined by the CCK-8 assay and EdU staining, respectively. The cell cycle and apoptosis were evaluated by flow cytometry. Enzyme-linked immunosorbent assay was employed to measure the levels of interleukin(IL)-1β, tumor necrosis factor(TNF)-α, and IL-6. The mRNA levels of aggrecan, collagen type Ⅱ alpha 1 chain(COL2A1), and ERK were determined by qRT-PCR, and the protein levels of aggrecan, COL2A1, and p-ERK were determined by Western blot. The results showed that compared with the model group, the treatments with drug-containing serum, blank Exos, and normal serum Exos enhanced the viability and proliferation of NPCs, decreased the proportion of cells in the G_0/G_1 phase, increased the proportion of cells in the S phase, reduced apoptosis, lowered the levels of IL-1β, TNF-α, and IL-6, up-regulated the mRNA and protein levels of aggrecan and COL2A1, and down-regulated the mRNA level of ERK and the protein level of p-ERK. Compared with the drug-containing serum, blank Exos, and normal serum Exos groups, the treatment with drug-containing serum Exos enhanced the viability and proliferation of NPCs, decreased the proportion of cells in the G_0/G_1 phase, increased the cells in the S phase, reduced apoptosis, lowered the levels of IL-1β, TNF-α, and IL-6, up-regulated the mRNA and protein levels of aggrecan and COL2A1, and down-regulated the mRNA level of ERK and the protein level of p-ERK. The results confirmed that the Exos secreted by ADSCs after treatment with Bushen Huoxue Decoction-containing serum promoted the proliferation of degenerated NPCs, inhibited apoptosis and the expression of inflammatory mediators, and promoted the production of proteoglycans and collagen, thus delaying the progression of intervertebral disc degeneration, the mechanism of which was related to the regulation of the ERK signaling pathway.