Treatment with bone marrow mesenchymal stem cells combined with plumbagin alleviates spinal cord injury by affecting oxidative stress, inflammation, apoptotis and the activation of the Nrf2 pathway

The aim of the present study was to investigate the protective effect exerted by bone marrow mesenchymal stem cells (BMSCs) in combination with plumbagin on spinal cord injury (SCI) and explore the mechanism behind this protective effect. Firstly, BMSCs were extracted from male Sprague-Dawley rats, cultured in vitro, and identified by hematoxylin. Sprague-Dawley rats were then randomly divided into a control group, SCI model group, BMSC-treated group, a plumbagin-treated group, and a BMSC and plumbagin-treated group. After treatment with BMSCs combined with plumbagin, a Basso, Beattie and Bresnahan (BBB) test was carried out and the spinal cord water content was examined in order to analyze the effect of BMSCs combined with plumbagin on SCI. The myeloperoxidase (MPO), superoxide dismutase (SOD), malondialdehyde (MDA), nuclear factor-kappa B (NF-kappa B) p65 unit, tumor necrosis factor-alpha (TNF-alpha) levels were also detected. Moreover, nuclear factor erythroid 2-related factor 2 (Nrf2), phosphoinositide 3-kinase (PI3K), phosphorylated (p-)Akt, p-p38 mitogen-activated protein kinase (MAPK), and p-extracellular-signal-regulated kinase (ERK) protein expression levels were measured using western blot analysis. Treatment with BMSCs combined with plumbagin significantly improved locomotor recovery and reduced the spinal cord water content after SCI. The increased MPO, MDA, NF-kappa B p65 and TNF-alpha levels were significantly suppressed and the decreased SOD was significantly increased in SCI rats. The suppression of Nrf2, p-Akt and p-ERK, as well as the promotion of p-p38 MAPK, were reversed by treatment with BMSCs combined with plumbagin. These effects suggest that treatment with BMSCs combined with plumbagin alleviates SCI through its effects on oxidative stress, inflammation, apoptotis and activation of the Nrf2 pathway.