To review the advance in the experimental studies and evaluate the potential therapeutic appl ication of the growth differentiation factor 5(GDF-5) and osteogenic protein 1 (OP-1) in intervertebral disc degeneration.Methods Relevant l iterature at home and abroad publ ished in recent years was searched and analyzedcomprehensively. Results The growth factor was one of the most potential proteins in curing the intervertebral discdegeneration. In vitro, exogenous GDF-5 or OP-1 increased the deoxyribonucleic acid and proteoglycan contents ofboth nucleus pulposus and annlus fibrosis cells types significantly. GDF-5 at 200 ng/mL or OP-1 significantly stimulatedproteoglycan synthesis and collagen synthesis. In vivo, the injection of GDF-5(100 μg) or OP-1(100 μg in 10 μL 5% lactose) resulted in a restoration of disc height, improvement of magnetic resonance imaging scores, and histologic grading scores had statistical significance. Conclusion A single injection of GDF-5 or OP-1 has a reparative capacity on intervertebral discs, presumably based on its effect to stimulate matrix metabol ism of intervertebral disc cells and enhance extracellular matrix production. A single injection of exogenous GDF-5 or OP-1 in the degenerated disc shows a good prospect.
Objective To investigate the effect of local injection of curcumin-loaded mesoporous silica nanoparticles (Cur@MSN) on the repair and treatment of degenerative intervertebral disc tissue in rats, and provide a new strategy for the treatment of intervertebral disc degeneration. Methods Mesoporous silica nanoparticles (MSN) and Cur@MSN were prepared according to the method reported in the literature. Rat nucleus pulposus cells were co-cultured with curcumin and Cur@MSN, respectively, and the growth status and activity of cells in normal environment and inflammatory environment (adding lipopolysaccharide) were observed respectively. Twelve 8-week-old SD rats were randomly divided into 4 groups, including normal group, degeneration group, curcumin group, and Cur@MSN group, with 3 rats in each group. Acupuncture degeneration model was established in coccygeal intervertebral discs (Co7-8, Co8-9) of rats, and corresponding intervention were injected. Imaging, gross pathology, and histological examination were performed after 4 weeks, respectively, to observe the tissue structure and pathological changes of intervertebral discs. Results Under scanning electron microscope, Cur@MSN was spherical in shape, with groove-like pores on its surface. Particle size analysis showed that the particle size of MSN was concentrated in 120-160 nm, and that of Cur@MSN was distributed in 130-170 nm. Zeta potential analysis showed that the average Zeta potential of MSN, curcumin, and Cur@MSN was −12.5, −22.5 and −13.5 mV, respectively. The entrapment efficiency of Cur@MSN was 20.4%, and the drug loading rate was 0.2%. Curcumin released by Cur@MSN in 12 h accounted for about 60% of the total drug dose, and curcumin released in 28 h accounted for about 70%. In cell experiment, there was no significant difference in cell proliferation absorbance among the groups in normal environment (P>0.05), but the cell proliferation absorbance in the Cur@MSN group on the 3rd and 5th day in inflammatory environment was significantly higher than that in the control group and the curcumin group (P<0.01). The percentage of disc height index and the Pfirrmann grade of the Cur@MSN group were better than those of the degeneration group and the curcumin group (P<0.01). The histological score of the Cur@MSN group was lower than that of the degeneration group and the curcumin group (P<0.01). Conclusions Cur@MSN can delay the degeneration process of rat coccygeal intervertebral disc, and has certain repair and treatment effects on its degenerated intervertebral disc. Among them, curcumin can delay the degeneration of intervertebral disc by inhibiting inflammation, and the loading of MSN is helpful for curcumin to exert its biological effects.
ObjectiveTo investigate the influence of ISOBAR TTL dynamic internal fixation system on degeneration of adjacent intervertebral disc by MRI measurement of lumbar nucleus pulposus volume in treating lumbar degenerative disease after operation. MethodsBetween March 2010 and October 2011, 34 patients with lumbar intervertebral disc herniation (23 cases of paracentral type and 11 cases of lateral type) underwent operation with ISOBAR TTL dynamic internal fixation system for fixation of single segment, and the clinical data were analyzed retrospectively. There were 20 males and 14 females, aged 39-62 years (mean, 47.5 years). The disease duration was 6-18 months (mean, 14 months). Involved segments included L4, 5 in 21 cases and L5, S1 in 13 cases. The X-ray films and MRI images were taken at 6, 12, 18, 24, 36, and 48 months after surgery. Based on X-ray films, the height of intervertebral space was measured using angle bisectrix method. The nucleus pulposus volume was measured based on the MRI scan. The postoperative change of nucleus pulposus volume and intervertebral disc height were used to evaluate the influence of ISOBAR TTL system on degeneration of adjacent intervertebral disc nucleus pulposus. ResultsThirty patients were followed up 48 months. The height of intervertebral space showed no significant difference between at pre-and post-operation (P>0.05). The nucleus pulposus volume increased after operation, showing no significant difference at 6, 12, and 18 months when compared with preoperative value (P>0.05), but significant difference was found at 24, 36, and 48 months when compared with preoperative value (P < 0.05). The height of nucleus pulposus increased after operation but the width was decreased; the values showed no significant difference at 6, 12, and 18 months when compared with preoperative ones, but showed significant difference at 24, 36, and 48 months when compared with preoperative ones (P < 0.05). The diameter of nucleus pulposus at 18, 24, 36, and 48 months after operation was significantly langer than that at preoperation (P < 0.05). ConclusionISOBAR TTL dynamic internal fixation system can prevent or delay the degeneration of intervertebral discs.
ObjectiveTo investigate the expression of p16INK4a in nucleus pulposus (NP) and to clarify its relationship with intervertebral disc degeneration so as to provide evidence for biological repair of intervertebral disc. MethodsThe NP specimens were obtained from 17 patients with intervertebral disc degeneration undergoing discectomy, who aged 40-50 years (mean, 45.4 years). Based on the preoperative MRI, there were 10 cases of grade Ⅲ degeneration, and 7 cases of grade IV degeneration. Cell senescence was evaluated by detecting senescence-associated β-galactosidase (SA-β-gal) activity. Senescence marker (p16INK4a) and disc degeneration markers [A disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS 5), Aggrecan, and Sryrelated HMG box transcri ption factor 9 (Sox-9)] were determined in the NP specimens with immunohistochemistry and Western blot. The correlation between ADAMTS 5 and p16INK4a was analyzed. ResultsClustered distribution of green SA-β-gal-positive cells was seen in the NP with grade Ⅲ and IV degeneration. A few single round SA-β-gal-positive NP cells (NPCs) wrapped by the layered extracellular matrix were also seen in the NP with grade Ⅲ degeneration. It was difficult to see single distribution of NPCs in the NP with grade IV degeneration. The percentage of SA-β-gal-positive cells was 22.7%±5.4% and 37.1%±7.6% in the NP with grade Ⅲ and IV degeneration respectively, showing significant difference (t=-9.666, P=0.000). The percentages of p16INK4a-positive and ADAMTS 5-positive NPCs in the NP with grade IV degeneration were significantly higher than those with grade Ⅲ degeneration (P<0.05). The percentages of Aggrecan-positive and Sox-9-positive NPCs in the NP with grade IV degeneration were significantly lower than those in the NP with grade Ⅲ degeneration (P<0.05). The protein expressions of Aggrecan and Sox-9 in the NP with grade IV degeneration were significantly lower than those in the NP with grade Ⅲ degeneration (P<0.05). The NP with grade IV degeneration showed significantly higher protein expressions of p16INK4a and ADAMTS 5 (P<0.05). Importantly, there was a good correlation between p16INK4a and ADAMTS 5 protein expressions (r=0.908, P=0.000). ConclusionPremature senescent NPCs increase in the NP with the advancing disc degeneration. The expression of p16INK4a and its association with degeneration grades suggest that the p16INK4a may play a significant role in the pathogenesis of intervertebral disc degeneration.
Objective To review the progress of the mechanisms of Wnt/β-catenin and nuclear factor-kappa B (NF-кB) pathways in the process of the intervertebral disc degeneration. Methods The related literature about the mechanisms of Wnt/β-catenin and NF-кB pathways in the process of the intervertebral disc degeneration was reviewed, analyzed, and summarized. Results Wnt/β-catenin and NF-кB pathways are both activated in the process of the intervertebral disc degeneration, and exist interaction. However, the specific mechanisms and interactive mediums of Wnt/β-catenin and NF-кB pathways in the process of the intervertebral disc degeneration are still unclear. Conclusion The mechanisms of Wnt/β-catenin and NF-кB pathways in the process of the intervertebral disc degeneration have to be studied deeply.
Extracellular vesicles (EVs), defined as cell-secreted nanoscale vesicles that carry bioactive molecules, have emerged as a promising therapeutic strategy in tumor and tissue regeneration. Their potential in repairing intervertebral disc degeneration (IDD) through multidimensional regulatory mechanisms is a rapidly advancing field of research. This paper provided an overview of the mechanisms of EVs in IDD repair, thoroughly reviewed recent literature on EVs for IDD, domestically and internationally, and summarized their therapeutic mechanisms. In IDD repair, EVs could act through different mechanisms at the molecular, cellular, and tissue levels. At the molecular level, EVs could treat IDD by inhibiting inflammatory reactions, suppressing oxidative stress, and regulating the synthesis and decomposition of extracellular matrix. At the cellular level, EVs could treat IDD by inhibiting cellular pyroptosis, ferroptosis, and apoptosis and promoting cell proliferation and differentiation. At the tissue level, EVs could treat IDD by inhibiting neovascularization. EVs have a strong potential for clinical application in the treatment of IDD and deserve more profound study.
Objective To summarize the role of cellular senescence and senescent secretary phenotype in the intervertebral disc (IVD) degeneration. Methods Relevant articles that discussed the roles of cellular senescence in the IVD degeneration were extensively reviewed, and retrospective and comprehensive analysis was performed. The senescent phenomenon during IVD degeneration, senescent secretary phenotype of the disc cells, senescent pathways within the IVD microenvironment, as well as the anti-senescent approaches for IVD regeneration were systematically reviewed. Results During aging and degeneration, IVD cells gradually and/or prematurely undergo senescence by activating p53-p21-retinoblastoma (RB) or p16INK4A-RB senescent pathways. The accumulation of senescent cells not only decreases the self-renewal ability of IVD, but also deteriorates the disc microenvironment by producing more inflammatory cytokines and matrix degrading enzymes. More specific senescent biomarkers are required to fully understand the phenotype change of senescent disc cells during IVD degeneration. Molecular analysis of the senescent disc cells and their intracellular signaling pathways are needed to get a safer and more efficient anti-senescence strategy for IVD regeneration. Conclusion Cellular senescence is an important mechanism by which IVD cells decrease viability and degenerate biological behaviors, which provide a new thinking to understand the pathogenesis of IVD degeneration.
Objective To explorer the survival time of autogeneic BMSCs labeled by superparamagnetic iron oxide (SPIO) in rabbit intervertebral discs and the rule of migration so as to prove bases of gene therapy preventing intervertebral disc degeneration. Methods Twelve rabbits were used in this experiment, aged 8-10 weeks, weighing 1.5-2.0 kg and neglecting their gender. BMSCs were separated from rabbits bone marrow by density gradient centrifugation and cultivated, and the 3rd generation of BMSCs were harvested and labeled with SPIO, which was mixed with poly-l-lysine. The label ing efficiency was evaluated by Prussian blue staining and transmission electron microscope. Trypanblau stain and MTT were performed to calculate the cell’ s activity. Rabbits were randomly divided into experimental group (n=8) and control group (n=4), the labeled BMSCs and non-labeled BMSCs (5 × 105/mL) were injected into their own intervertebral discs (L1,2, L2,3, L3,4 and L4,5), respectively. At 2, 4, 6 and 8 weeks, the discs were treated with Perl’s fluid to observe cell survival and distribution. Results The label ing efficiency of BMSCs with SPIO was 95.65% ± 1.06%, the cell activity was 98.28% ± 0.85%. There was no statistically significant difference in cell prol iferation within 7 days between non-labeled and labeled cells (P gt; 0.05). After 8 weeks of operation, the injected cells was al ive. ConclusionLabeled BMSCs with SPIO is feasible in vitro and in vivo, and the cells can survive more than 8 weeks in rabbit discs.
Objective To develop a modified short time inversion recovery (STIR) sequence grading system for lumbar intervertebral disc degeneration based on MRI STIR sequences, and to test the validity and reproducibility of this grading system. Methods A modified 8-level grading system for lumbar intervertebral disc degeneration based on routine sagittal STIR sequences and modified Pfirrmann grading system was developed. Between April 2011 and February 2012, 60 patients with different degrees of lumbar intervertebral disc degeneration were selected as objects of study, including 32 males and 28 females with an average of 50 years (range, 17-85 years). T2 weighted and STIR sequence images were obtained from the lumbar discs of L1, 2-L5, S1 of each object (total, 300 discs). All examinations were analyzed independently by 3 observers and a consensus readout was performed after all data collected. The validity and reproducibility were analyzed by calculating consistent rate and Kappa value. Results According to the grading system, there were 0 grade 1, 83 (27.7%) grade 2, 87 (29.0%) grade 3, 66 (22.0%) grade 4, 31 (10.3%) grade 5, 15 (5.0%) grade 6, 12 (4.0%) grade 7, and 6 (2.0%) grade 8. Intra-observer consistency was b (Kappa value range, 0.822-0.952), and inter-observer consistency was high to b (Kappa value range, 0.749-0.843). According to the consensus analysis, the total consistent rate was 82.7%-92.7% (mean, 85.6%). A difference of one grade occurred in 13.9% and a difference of two or more grades in 0.5% of all the cases. Conclusion Disc degeneration can be graded by using modified STIR sequence grading system, which can improve the accuracy of grading different degrees of lumbar intervertebral disc degeneration.
Objective To evaluate the cell biological features and the effect of transplantation of transforming growth factor β3 (TGF-β3) gene-modified nucleus pulposus (NP) cells on the degeneration of lumbar intervertebral discs in vitro. Methods NP cells at passage 2 were infected by recombinant adenovirus carrying TGF-β3 (Ad-TGF-β3) gene (Ad-TGF-β3 group), and then the cell biological features were observed by cell vital ity assay, the expression of the TGF-β3 protein was determined by Western blot, the expression of collagen type II in logarithmic growth phase was determined by immunocytochemistry. The cells with adenovirus-transfected (Adv group) and the un-transfected cells (blank group) were used as controls. The model of lumbar disc degeneration was establ ished by needl ing L3, 4, L4, 5, and L5, 6 in 30 New Zealand rabbits (weighing 3.2-3.5 kg, male or female). Then Ad-TGF-β3-transfected rabbit degenerative nucleus pulposus cells (100 μL, 1 × 105/ mL, group A, n=12), no gene-modified nucleus pulposus cells (100 μL, 1 × 105/mL, group B, n=12), and phosphatebuffered sal ine (PBS, 100 μL, group C, n=6) were injected into degenerative lumbar intervertebral discs, respectively. L3, 4, L4, 5, and L5, 6 disc were harvested from the rabbits (4 in groups A and B, 2 in group C) at 6, 10, and 14 weeks respectively to perform histological observation and detect the expression of collagen type II and proteoglycan by RT-PCR. Results The viabil ity of nucleus pulposus cells was obviously improved after transfected by recombinant Ad-TGF-β3 gene. At 3, 7, and 14 days after transfected, TGF-β3 expression gradually increased in nucleus pulposus cells. The positive staining of collagen type II was seen in Ad-TGF-β3 group, and the positive rate was significantly higher than that of Adv group and blank group (P lt; 0.05). The disc degeneration in group A was sl ighter than that in groups B and C. The expressions of collagen type II mRNA and proteoglycan mRNA in group A were significantly higher than those in groups B and C at 6, 10, and 14 weeks (P lt; 0.05). Conclusion TGF-β3 can improve the biological activity of NP cells and promote the biosynthesis of collagen type II and proteoglycan in intervertebral discs, alleviate the degeneration of intervertebral discs after transplantation.