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.
Intervertebral Disc Degeneration/drug therapy* ; Apoptosis/drug effects* ; Nucleus Pulposus/cytology* ; Drugs, Chinese Herbal/pharmacology* ; Animals ; Rats ; MAP Kinase Signaling System/drug effects* ; Rats, Sprague-Dawley ; Collagen Type II/metabolism* ; Humans ; Cell Proliferation/drug effects* ; Stem Cells/metabolism* ; Aggrecans/metabolism* ; Cell Survival/drug effects* ; Male ; Cells, Cultured ; Tumor Necrosis Factor-alpha/metabolism*

This study aimed to investigate the effect of aucubin(AU) on injury of nucleus pulposus cells and extracellular matrix(ECM) degradation and its mechanism. The nucleus pulposus cell injury model was established by interleukin-1β(IL-1β) and treated with AU or phosphatidylinositol 3-kinase(PI3K) inhibitor LY294002. CCK-8 experiment was conducted to test cell proliferation. EdU staining method was employed to detect cell injury. Flow cytometry was used to detect cell apoptosis. Western blot was used to detect protein levels of cleaved-caspase-3, B-cell lymphoma(Bcl-2), Bcl-2 associated X protein(Bax), type Ⅱ collagen(collagen Ⅱ), aggregation proteoglycans(aggrecan), PI3K, and mammalian target of rapamycin(mTOR). qPCR was used to detect the rRNA level of 5S, 18S, and 28S. Ethynyluridine was used to label nascent RNA. The results showed that IL-1β could significantly cause injury of nucleus pulposus cells and increase the apoptosis rate of nucleus pulposus cells and the expression of apoptosis protein cleaved-caspase-3 and Bax. At the same time, IL-1β down-regulated the expression of anti-apoptotic protein Bcl-2 and collagen Ⅱ and aggrecan, the main components of ECM. On this basis, AU intervention could improve the injury of nucleus pulposus cells, reduce the apoptosis of nucleus pulposus cells and the expression of cleaved-caspase-3 and Bax, and increase the expression of Bcl-2, collagen Ⅱ, and aggrecan. Compared with IL-1β, AU could up-regulate the phosphorylation level of PI3K and mTOR, and LY294002 could reverse the injury of nucleus pulposus cells and improve ECM degradation induced by AU. In addition, AU also could save lowered rRNA levels of 5S, 18S, and 28S induced by IL-1β and improve RNA synthesis. PI3K inhibitor LY294002 intervention could reduce the promoting effect of AU on ribosome biogenesis. The above results suggest that AU can improve the injury of nucleus pulposus cells and ECM degradation, and its mechanism of action is related to its activation of the PI3K/mTOR pathway to promote ribosome biogenesis.
Nucleus Pulposus/cytology* ; Extracellular Matrix/drug effects* ; Animals ; Iridoid Glucosides/pharmacology* ; Apoptosis/drug effects* ; Interleukin-1beta/metabolism* ; Phosphatidylinositol 3-Kinases/genetics* ; Rats ; Cell Proliferation/drug effects* ; TOR Serine-Threonine Kinases/genetics* ; Rats, Sprague-Dawley ; Humans ; Signal Transduction/drug effects* ; Caspase 3/genetics* ; Proto-Oncogene Proteins c-bcl-2/genetics*

This study investigated the mechanism by which kaempferol(KAE) affected intervertebral disc degeneration(IDD) through the p38 mitogen-activated protein kinase(p38 MAPK) signaling pathway. Rats were randomly divided into five groups: control group, model group, low-dose KAE group, medium-dose KAE group, and high-dose KAE group. An IDD model was established by needle puncture of the caudal intervertebral discs. Four weeks post-surgery, the rats were administered KAE via gavage for 8 consecutive weeks. Magnetic resonance imaging(MRI) was performed, and samples were collected. In vitro, an inflammation model of nucleus pulposus cells(NPCs) induced by tumor necrosis factor-alpha(TNF-α) was constructed. Anisomycin was used to activate the p38 MAPK signaling pathway. NPCs were divided into blank, model, KAE, agonist, and KAE + agonist groups. After 1 day of treatment, cell proliferation activity was assessed using the CCK-8. Protein expression levels were determined by Western blot, and mRNA expression was measured by real-time quantitative polymerase chain reaction. Cell apoptosis was detected by TUNEL staining, and immunofluorescence staining was used to detect type Ⅱ collagen and matrix metalloproteinase 3(MMP3). In vivo results indicated significant improvement in the degree of IDD in the treatment groups compared to the model group, with the medium-dose group showing more pronounced therapeutic effects than the low-and high-dose groups. In vitro results demonstrated that KAE treatment significantly enhanced NPC proliferation activity, down-regulated the expression levels of Bcl-2-associated X protein(Bax), interleukin-6(IL-6), interleukin-17A(IL-17A), MMP3, and a disintegrin and metalloproteinase with thrombospondin motifs 5, and inhibited the phosphorylation of p38 MAPK pathway-related proteins. Activation of the p38 MAPK signaling pathway by anisomycin reduced the therapeutic effects of KAE. The study concluded that KAE could improve the proliferation activity of degenerated NPCs, reduce inflammation levels, and slow the progression of IDD in rats, and the mechanism was likely related to the regulation of the p38 MAPK signaling pathway.
Animals ; p38 Mitogen-Activated Protein Kinases/genetics* ; Kaempferols/pharmacology* ; Intervertebral Disc Degeneration/genetics* ; Rats ; Rats, Sprague-Dawley ; Male ; Apoptosis/drug effects* ; Cell Proliferation/drug effects* ; Nucleus Pulposus/drug effects* ; Signal Transduction/drug effects* ; Humans ; MAP Kinase Signaling System/drug effects*