Bin Ning

Recombinant human erythropoietin prevents motor neuron apoptosis in a rat model of cervical sub-acute spinal cord compression.

The objective of the study was to investigate the effects of recombinant human erythropoietin (rhEPO) in a rat model of cervical sub-acute spinal cord compression. 80 Wistar rats were randomly divided into 4 groups. Rats in the sham group (Group A, n=5) underwent surgical procedures without cervical spinal cord compression; while rats in other groups were subjected to the spinal compression process. In the control group (Group B, n=25), rats received an i.v. injection of 1 mL saline at day 7 post-surgery. Rats in the low-dose group (Group C, n=25) and the high-dose group (Group D, n=25) were treated with rhEPO at 500 units/kg body-weight and 5000 units/kg, respectively, via intravenous injection at day 7 post surgery. Limb motor function was scored by Basso-Beattie-Bresnahan (BBB) standards at 3, 7, 14, 21 and 28 days post-surgery. The distribution and quantities of EPO and its receptor (EPO-R) in the compressed segment of the spinal cord were detected by immunohistochemistry. Motor neuron apoptosis in the spinal cord was evaluated using TUNEL staining and flow cytometry at the indicated time points. Finally, IL-8, TNF-α, IL-6, and IL-1β levels in the compressed cervical spinal cord were determined by ELISA within the lesion epicenter at each time point post-surgery. The data suggest that expression of EPO-R was significantly increased following sub-acute cervical spinal cord compression; Groups C and D exhibited better BBB scores at all observed time points compared with the control group (p<0.01). Using TUNEL staining and FCM, we observed that rhEPO profoundly inhibited motor neuron apoptosis in the spinal cord at day 21 (p<0.01). Additionally, treatment with rhEPO halted the elevation of inflammatory cytokines. rhEPO administration decreased motor neuron apoptosis in the cervical spinal cord, improved motor functions and reduced the inflammatory response in a sub-acute cervical spinal cord compression model. Moreover, sustained treatment with low doses of rhEPO revealed a positive therapeutic effect.

Antigen-Specific Tolerogenic Dendritic Cells Ameliorate the Severity of Murine Collagen-Induced Arthritis

Dendritic cells (DCs) play important roles in initiation of the pathogenic processes of autoimmune disorders, such as rheumatoid arthritis (RA). Tolerogenic dendritic cells (tolDCs) are generated from naïve DCs and induce T cell tolerance; thus, they represent a promising strategy for specific cellular therapy for autoimmune diseases. In this study, we generated green fluorescent protein (GFP)-labeled tolDCs and confirmed their phenotypes and biological functions. We found that tolDCs suppressed the memory lymphocyte response and exhibited strong tolerogenic potential; thus, these cells show promise for the treatment of autoimmune diseases. Additionally, a collagen-induced arthritis (CIA) mouse model was used to test the role of tolDCs in vivo. The results of a further mechanistic experiment revealed that tolDCs suppressed inflammatory arthritis at least partially by up-regulating regulatory T (Treg) cells. Collectively, our data suggest that tolDCs may be used as a promising alternative therapy for inflammatory arthritis.

Tolerogenic dendritic cells and rheumatoid arthritis: current status and perspectives

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by the influxation of synovia and synovial compartments with immune cells including dendritic cells (DCs). DCs that induce autoimmune tolerance are called tolerogenic DCs (tolDCs). As a promising immunotherapeutic strategy for RA, tolDCs have received increasing attention. In this review, we first introduce the significant role of tolDCs in autoimmune regulation and then describe the manipulation strategies to generate tolDCs; next, we summarize recent progress in the experimental application of tolDCs for RA therapy, and finally we discuss the perspectives of tolerogenic vaccination for the treatment for RA in clinic.

Local Gene Transfer of OPG Prevents Joint Damage and Disease Progression in Collagen-Induced Arthritis

This study examined the influence of osteoprotegerin (OPG) gene transfer on a murine collagen-induced arthritis model. A single periarticular injection of AAV-OPG or AAV-LacZ on the arthritic paw successfully incorporated the exogenous gene to the local tissue and resulted in marked transgene expression in the joint homogenate for at least three weeks. Clinical disease scores were significantly improved in OPG treated mice starting at 28-day post-treatment (P < 0.05). Histological assessment demonstrated that OPG gene transfer dramatically protected mice from erosive joint changes compared with LacZ controls (P < 0.05), although treatment appeared less effective on the local inflammatory progress. MicroCT data suggested significant protection against subchondral bone mineral density changes in OPG treated CIA mice. Interestingly, mRNA expressions of IFN-g and MMP3 were noticeably diminished following OPG gene transfer. Overall, gene transfer of OPG effectively inhibited the arthritis-associated periarticular bone erosion and preserved the architecture of arthritic joints, and the study provides evidence that the cartilage protection of the OPG gene therapy may be associated with the down-regulation of MMP3 expression.

Regulatory roles of microRNA-21 in fibrosis through interaction with diverse pathways (Review).

MicroRNA-21 (miR-21) is a small, non-coding RNA which can regulate gene expression at the post‑transcriptional level. While the fibrogenic process is vital in tissue repair, proliferation and transition of fibrogenic cells combined with an imbalance of secretion and degradation of the extracellular matrix results in excessive tissue remodeling and fibrosis. Recent studies have indicated that miR‑21 is overexpressed during fibrosis and can regulate the fibrogenic process in a variety of organs and tissues via diverse pathways. The present review summarized the significant roles of miR-21 in fibrosis and discussed the underlying key pathways.

Microcarrier bioreactor culture system promotes propagation of human intervertebral disc cells

BackgroundCell-based tissue engineering has emerged as a potential therapy for intervertebral disc degeneration. However, propagating and maintaining high quantity and quality of the seed cells remains a challenge.AimsTo investigate the feasibility of culturing human disc cells using a microcarrier bioreactor system.MethodsCell counts, growth patterns, cell cycles and cellular viability were examined during the course of cell cultivation and compared between the microcarrier bioreactor culture system and the conventional monolayer culture.ResultsCultures in the microcarrier bioreactor resulted in enhanced disc cell growth and satisfactory cell viability in comparison with the conventional monolayer culture. The cells in the microcarrier bioreactor cultivation exhibited higher S phase ratios, elevated mitotic index and persistent exponential growth.ConclusionThe microcarrier bioreactor culture system appears suitable for human disc cell propagation and may provide considerably more seeding cells for the tissue engineering process of intervertebral discs.

MicroRNA-21-5p mediates TGF-β-regulated fibrogenic activation of spinal fibroblasts and the formation of fibrotic scars after spinal cord injury

Little regeneration of transected axons occurs after the damage caused by traumatic spinal cord injury (SCI), and unidirectional and irreversible fibrotic scars are thought to be the main chemical and physical obstacle for axonal regrowth in SCI pathology. We previously demonstrated that microRNA (miR)-21-5p and transforming growth factor (TGF)-β1, a central pathological mediator of fibrotic diseases, were significantly up-regulated in the lesion epicenter after SCI. Here, we found that TGF-β1 enhanced miR-21-5p expression in primary spinal fibroblasts, and regulated the expression of fibrosis-related genes. The overexpression of miR-21-5p promoted the pro-fibrogenic activity of TGF-β1 in spinal fibroblasts, while miR-21-5p knockdown attenuated this activity. We identified Smad7 as a target gene of miR-21-5p, suggesting a potential mechanism for the role of miR-21-5p in spinal fibrosis through regulating Smad7 expression. Furthermore, miR-21-5p knockdown in a mouse model significantly improved motor functional recovery after spinal cord injury. These data demonstrate that miR-21-5p functions in an amplifying circuit to enhance TGF-β signaling events in the activation of spinal fibroblasts and suggest that miR-21-5p is a potential therapeutic target in the treatment of fibrotic scar formation after SCI.

Neuroprotective mechanisms of rutin for spinal cord injury through anti-oxidation and anti-inflammation and inhibition of p38 mitogen activated protein kinase pathway

Rutin has anti-inflammatory, antioxidant, anti-viral, anti-tumor and immune regulatory effects. However, the neuroprotective effects of rutin in spinal cord injury are unknown. The p38 mitogen activated protein kinase (p38 MAPK) pathway is the most important member of the MAPK family that controls inflammation. We assumed that the mechanism of rutin in the repair of spinal cord injury is associated with the inhibition of p38 MAPK pathway. Allens method was used to establish a rat model of spinal cord injury. The rat model was intraperitoneally injected with rutin (30 mg/kg) for 3 days. After treatment with rutin, Basso, Beattie and Bresnahan locomotor function scores increased. Water content, tumor necrosis factor alpha, interleukin 1 beta, and interleukin 6 levels, p38 MAPK protein expression and caspase-3 and -9 activities in T8–9 spinal cord decreased. Oxidative stress related markers superoxide dismutase and glutathione peroxidase levels increased in peripheral blood. Rutin exerts neuroprotective effect through anti-oxidation, anti-inflammation, anti-apoptosis and inhibition of p38 MAPK pathway.

Surgically‑induced mouse models in the study of bone regeneration: Current models and future directions (Review)

Bone regeneration has been extensively studied over the past several decades. The surgically-induced mouse model is the key animal model for studying bone regeneration, of the various research strategies used. These mouse models mimic the trauma and recovery processes in vivo and serve as carriers for tissue engineering and gene modification to test various therapies or associated genes in bone regeneration. The present review introduces a classification of surgically induced mouse models in bone regeneration, evaluates the application and value of these models and discusses the potential development of further innovations in this field in the future.

Biological characteristics of adult degenerative nucleus pulposus cells in a three-dimensional microcarrier stirring culture system

A major problem in reconstructing degenerative intervertebral discs is to obtain sufficient nucleus pulposus (NP) seeding cells with normal physiologic functions. The current study adopted a three‐dimensional microcarrier culture system for massive cell expansion and evaluated the biological characteristics and physiological functions of the propagated adult degenerative NP cells. Isolated adult NP cells were cultured in either microcarrier stirring culturing system or traditional monolayer cultivation. The growth characteristics, proliferation, extracellular matrix secretion, and apoptosis potential were examined to evaluate the different features of the two cultivation methods. Compared to the monolayer cultivation system, the adhesion time of NP cells in the three‐dimensional microcarrier culture system appeared longer with relatively transient stable growth period. MTT and 3H‐TdR assays suggested significantly elevated proliferation and higher thymidine incorporation rates in cells from microcarrier system compare to cells in the monolayer system at the exponential growth phase (p < 0.05). Western blot data complimented the immunostaining results that the NP cells in the microcarrier system expressed significantly more protein levels of both type collagens at the exponential growth phase than that in the monolayer system (p < 0.05). Further, significantly more 35S labeled proteoglycan incorporation was noticed in the cells on the microcarriers at both the stable growth and the exponential growth phases (p < 0.05 and p < 0.01). In conclusion, the three‐dimensional microcarrier stirring culture system provides a means of fast and massive propagation of NP seeding cells which maintain their normal physiological characteristics and functions.