淫羊藿苷调控髓核来源间充质干细胞凋亡修复椎间盘退变.

BACKGROUND: Intervertebral disc degeneration is one of the most common causes of low back pain. The decrease in the number and dysfunction of endogenous nucleus pulposus-derived mesenchymal stem cells may be an important cause of intervertebral disc degeneration. Icariin within a certain range may reduce the apoptosis of mesenchymal stem cells through the PI3K/Akt signaling pathway. OBJECTIVE: To investigate the mechanisms underlying the effects of icariin on apoptosis of nucleus pulposus-derived mesenchymal stem cells. METHODS: The nucleus pulposus-derived mesenchymal stem cells were isolated from degenerated disc of Sprague-Dawley rats. Nucleus pulposus-derived mesenchymal stem cells of passage 3 were treated with different concentrations of icariin. CCK-8 assay was used to detect cell viability and proliferation. Nucleus pulposus-derived mesenchymal stem cells of passage 3 were divided into control, icariin, and LY294002 groups. The apoptosis was detected by flow cytometry and TUNEL staining at 1 week after treatment. The mRNA and protein expression of Caspase-3, Bcl-2, Bax and PI3K/Akt signaling pathway-related proteins p-Akt and p53 was detected by real-time polymerase chain reaction and western blotting. Sixteen Sprague-Dawley rat intervertebral disc degeneration models were equally divided into icariin (icariin 50 mg/kg per day intragastrically) and control groups (equivalent normal saline intragastrically). X-ray, MRI and hematoxylin-eosin staining were performed to evaluate disc degeneration before, 2 and 4 weeks after treatment. RESULTS AND CONCLUSION: (1) Icariin promoted the proliferation of nucleus pulposus-derived mesenchymal stem cells at a certain concentration range, and the best concentration was 0.1 μmol/L (P < 0.05). (2) The apoptosis rate, the number of TUNEL-positive cells, mRNA and protein expression of Caspase-3, Bax and p53 in the icariin group were significantly decreased compared with the control group, while the expression levels of p-Akt and Bcl-2 were significantly increased (P < 0.05). LY294002 (PI3K/Akt signaling pathway inhibitor) reversed the protective effect of icariin on nucleus pulposus-derived mesenchymal stem cells (P < 0.05). (3) The disc degeneration was delayed after icariin treatment in the animal models. There were significant differences in the Disk Height Index, MRI scores, and hematoxylin and eosin staining scores between the icariin and control groups at 4 weeks (P < 0.05). (4) The results show that icariin can promote the proliferation of nucleus pulposus-derived mesenchymal stem cells in a concentration-dependent manner within a certain concentration range. Furthermore, icariin can inhibit nucleus pulposus-derived mesenchymal stem cell apoptosis by activating PI3K/Akt signaling pathway to delay disc degeneration. [ABSTRACT FROM AUTHOR]