To detect the cell density, apoptotic incidence and the expressions of Bax and Caspase-3in human lumbar intervertebral discs, so as to further understand the mechanism of human lumbar intervertebral discdegeneration and provide a new idea for biologic treatment of it in future. Methods From May to December in 2006,30 human lumbar intervertebral discs in experimental group(L2 to S1)were surgically collected from 27 patients undergoing posterior lumbar intervertebral discoidectomy and fusion. All the cases were affirmed by MRI and they never experienced discography, collagenolysis of nucleus pulposus and percutaneous laser disc decompression. The control group consisted of 20 human lumbar intervertebral discs(L2 to S1)harvested from 5 young men without spine-related condition immediately after their accidental death. Apoptotic disc cells were detected by TUNEL and histomorphology, and immunohistochemical staining with SP method was performed to examine the expressions of Bax and Caspase-3 in all specimens. Results HE staining disclosed that the average cell density in control group (17.16 ± 1.22)/HP was higher than that in experimental group (12.41 ± 0.95)/HP (P lt; 0.01). However, TUNEL staining observed that the average TUNEL positive incidence in control group (6.97% ± 0.92%) was lower than that in experimental group (12.59% ± 0.95%), (P lt; 0.01). Immunohistochemical staining with SP method showed that the Bax and Caspase-3 positive incidence of nucleus pulposus in control group (11.02% ± 1.18%, 9.01% ± 1.00%) were lower than those in experimental group (19.29% ± 1.18%, 15.07% ± 0.97%), (P lt; 0.01). The results of the average gray scale value of nucleus pulposus in control group were 187.33 ± 7.88 and 185.68 ± 3.26, respectively, with 124.98 ±6.69 and 160.13 ± 4.37 in experimental group. There was significant difference between the two groups (P lt; 0.01). When thetotal 50 specimens in the two groups were analyzed, TUNEL positive incidence showed significant inverse correlations with their respectively corresponding cell densities (r = － 0.88, r = － 0.93, P lt; 0.01). The Bax and Caspase-3 positive incidence of nucleus pulposus showed significant positive correlation with the TUNEL positive incidence of nucleus pulposus (r = 0.83, r = 0.91, P lt; 0.01). Conclusion The decrease of cell density is involved in the development of human lumbar intervertebral disc degeneration. Bax and Caspase-3 might play a role in disc cell apoptosis in nucleus pulposus of human lumbar intervertebral disc.
Objective To investigate the effects of human insulin-like growth factor 1 (hIGF-1) gene transfected by recombinant adenovirus vector (Ad-hIGF-1) on the apoptosis of rabbit nucleus pulposus cells induced by tumor necrosis factor α (TNF-α). Methods The intervertebral disc nucleus pulposus were harvested from 8 healthy adult domestic rabbits (male or female, weighing 2.0-2.5 kg). The nucleus pulposus cells were isolated with collagenase II digestion and the passage 2 cells were cultured to logarithm growing period, and then they were divided into 3 groups according to culture condition: DMEM/F12 medium containing 10% PBS, DMEM/F12 medium containing 10% PBS and 100 ng/mL TNF-α, and DMEM/ F12 medium containing 10% PBS, 100 ng/ mL TNF-α, and Ad-hIGF-1 (multiplicity of infection of 50) were used in control group, TNF-α group, and Ad-hIGF-1 group, respectively. The results of transfection by adenovirus vector carrying hIGF-1 gene were observed by fluorescent microscopy; the expression of hIGF-1 protein was detected by Western blot, hIGF-1 mRNA expression by RT-PCR, and the cell apoptosis rate by TUNEL and flow cytometry. Results Green fluorescence was observed by fluorescent microscopy in Ad-hIGF-1 group, indicating that successful cell transfection. The expressions of hIGF-1 protein and mRNA were detected in Ad-hIGF-1 group by Western blot and RT-PCR, while the control group and TNF-α group had no expression. The cell apoptosis rates of TNF-α group, Ad-hIGF-1 group, and control group were 34.24% ± 4.60%, 6.59% ± 1.03%, and 0.40% ± 0.15%, respectively. The early apoptosis rates of TNF-α group, Ad-hIGF-1 group, and control group were 22.16% ± 2.69%, 5.03% ± 0.96%, and 0.49% ± 0.05%, respectively; the late cell apoptosis rates were 13.96% ± 4.86%, 10.68% ± 3.42%, and 0.29% ± 0.06%, respectively. Compared with TNF-α group, the cell apoptosis rates of Ad-hIGF-1 group and control group were significantly reduced (P lt; 0.05); the cell apoptosis rate of Ad-hIGF-1 group was significantly higher than that of control group (P lt; 0.05). Conclusion Ad-hIGF-1 could inhibit the apoptosis of nucleus pulposus cells induced by TNF-α.
Objective To review the mechanism of extracellular vesicles (EVs) in treating intervertebral disc degeneration (IVDD). Methods The literature about EVs was reviewed and the biological characteristics and mechanism of EVs in the treatment of IVDD were summarized. Results EVs are a kind of nano-sized vesicles with a double-layered lipid membrane structure secreted by many types of cells. EVs contain many bioactive molecules and participate in the exchange of information between cells, thus they play important roles in inflammation, oxidative stress, senescence, apoptosis, and autophagy. Moreover, EVs are found to slow down the process of IVDD by delaying the pathological progression of the nucleus pulposus, cartilage endplates, and annulus fibrosus. Conclusion EVs is expected to become a new strategy for the treatment of IVDD, but the specific mechanism remains to be further studied.
Degenerative disc disease is a prevalent chronic disease that orthopaedic surgeons currently face as a difficulty. Tissue engineering represents the most promising possible therapeutic strategy for disc repair and regeneration. Surgery is the primary treatment for degenerative disc disease, but there are still inherent limits in practical practice. Electrospinning technique is a method for manufacturing nanoscale fibers with varied mechanical properties, porosity, and orientation, which can imitate the structural qualities and mechanical properties of natural intervertebral discs. Therefore, electrospinning materials can be utilized for disc regeneration and replacement. This article reviews recent advancements in disc tissue engineering and electrostatically spun nanomaterials typically utilized for the fabrication of disc scaffolds, as well as present and future techniques that may enhance the performance of electrostatically spun fibers.
Objective To review the l iterature about the multiple level artificial disc replacement and investigate the prel iminary the cl inical outcome of the first case in China applying three-level PRESTIGE® LP artificial disc replacement for cervical disc degenerative disease. Methods In April 2009, one female patient aged 44 years old was treated. She was diagnosed as disc protrusion at the C4, 5, C5, 6, and C6, 7 level. She had paresthesia, decreased muscle strength and positivepathological reflex in her left upper extremity. The neck disabil ity index (NDI) was 43. The visual analogue scale (VAS) of the neck and the upper l imb was 6.6 and 8.1, respectively. SF-36 physical and psychological score was 28 and 36, respectively. The surgery was performed via routine anterior cervical approach. After complete decompression of three segments, prostheses were implanted from the cephal ic to the caudal end under radiographic monitoring. The patient was followed up 1 and 3 months after operation, respectively. Results The time of operation was 220 minutes and the blood loss during operation was 270 mL. The incision healed by first intention. There was no occurrence of compl ications such as aggravation of nerve symptoms, hoarse voice, difficult in swallow, and cerebrospinal fluid leakage. At 3 months after the operation, the patient had pain rel ief, muscle force recovery and improvement of l ife qual ity. X-ray films showed that the sequence of cervical vertebra was well-maintained, there was no loosening and displacement of prosthesis, and the position and function were good. NDI was decreased to 7, indicating that the l imitation was mild. The VAS of the neck and the upper l imb was 0.5 and 0.6, respectively. SF-36 physical and psychological score was 48 and 53, respectively. The result of operation was graded as excellent according to Odom’s criterion. The patient went back to her job. Conclusion Three-level PRESTIGE® LP artificial disc replacement for cervical disc degenerative disease has satisfactory prel iminary cl inical results. However, more cl inical case studies and longer cl inical followup are needed to confirm its therapeutic effect on multi-level disc disease.
Objective To summarize the research progress of intervertebral disc endogenous stem cells for intervertebral disc regeneration and deduce the therapeutic potential of endogenous repair for intervertebral disc degeneration. Methods The original articles about intervertebral disc endogenous stem cells for intervertebral disc regeneration were extensively reviewed; the reparative potential in vivo and the extraction and identification in vitro of intervertebral disc endogenous stem cells were analyzed; the prospect of endogenous stem cells for intervertebral disc regeneration was predicted. Results Stem cell niche present in the intervertebral discs, from which stem cells migrate to injured tissues and contribute to tissues regeneration under certain specific microenvironment. Moreover, the migration of stem cells is regulated by chemokines system. Tissue specific progenitor cells have been identified and successfully extracted and isolated. The findings provide the basis for biological therapy of intervertebral disc endogenous stem cells. Conclusion Intervertebral disc endogenous stem cells play a crucial role in intervertebral disc regeneration. Therapeutic strategy of intervertebral disc endogenous stem cells is proven to be a promising biological approach for intervertebral disc regeneration.
Objective To investigate the therapeutic effect of BMSCs- chitosan hydrogel complex transplantation on intervertebral disc degeneration and to provide experimental basis for its cl inical appl ication. Methods Two mill il iter of bone marrow from 6 healthy one-month-old New Zealand rabbits were selected to isolate and culture BMSCs. Then, BMSCs at passage 3 were labeled by 5-BrdU and mixed with chitosan hydrogel to prepare BMSCs- chitosan hydrogel complex. Six rabbitswere selected to establ ish the model of intervertebral disc degeneration and randomized into 3 groups (n=2 per group): control group in which intervertebral disc was separated and exposed but without further processing; transplantation group in which 30 μL of autogenous BMSCs- chitosan hydrogel complex was injected into the center of defected intervertebral disc; degeneration group in which only 30 μL of 0.01 mol/L PBS solution was injected. Animals were killed 4 weeks later and the repaired discs were obtained. Then cell 5-BrdU label ing detection, HE staining, aggrecan safranin O staining, Col II immunohistochemical staining and gray value detection were conducted. Results Cell label ing detection showed that autogenous BMSCs survived and prol iferated after transplantation, forming cell clone. HE staining showed that in the control and transplantation groups, the intervertebral disc had a clear structure, a distinct boundary between the central nucleus pulposus and the outer anulus fibrosus, and the obviously stained cell nuclear and cytochylema; while the intervertebral disc in the degeneration group had a deranged structure and an indistinct division between the nucleus pulposus and the outer anulus fibrosus. Aggrecan safarine O stainning notified that intervertebral disc in the control and transplantation groups were stained obviously, with a clear structure; while the intervertebral disc in the degeneration group demonstrated a deranged structure with an indistinct division between the nucleus pulposus and the anulus fibrosus. Col II immunohistochemical staining showed that the tawny-stained region in the control group was located primarily in the central nucleus pulposus with a clear structure of intervertebral disc, the central nucleus pulposus in the transplantation group was positive with obvious tawny-stained intercellular substances and a complete gross structure, while the stained color in the degeneration group was l ighter than that of other two groups, with a indistinct structure.Gray value assay of Col II immunohistochemical staining section showed that the gray value of the control, the ransplantation and the degeneration group was 223.84 ± 3.93, 221.03 ± 3.53 and 172.50 ± 3.13, respectively, indicating there was no significant difference between the control and the transplantation group (P gt; 0.05), but a significant difference between the control and transplantation groups and the degeneration group (P lt; 0.05). Conclusion The rabbit BMSCs-chitosan hydrogel complex can repair intervertebral disc degeneration, providing an experimental foundation for the cl inical appl ication of injectable tissue engineered nucleus pulposus complex to treat intervertebral disc degeneration.
Intervertebral disc degeneration is a multifactorial pathological process which is one of the leading causes of disability worldwide. The main pathological changes of intervertebral disc degeneration are the degradation of extracellular matrix, apoptosis, autophagy, senescence and inflammation. Dysregulation of microRNAs has been implicated in various pathologies, including various degenerative diseases such as disc degeneration. This article reviews the research status of microRNA in degenerative disc pathology, with emphasis on the biological mechanisms and potential therapeutic prospects of microRNA in extracellular matrix degradation, apoptosis, inflammation, and cartilage endplate 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.
Objective To review the research advances in animal models of human disc degeneration. Methods The relative articles in recent years were extensively reviewed. Studies both at home and abroad were analyzed and classified. The advantages and disadvantages of each method were compared. Results Studies were classified as either experimentally induced models or spontaneous models. The induced models were subdivided as mechanical (alteration of forces on the normal disc), structural (injury or chemical alteration) and genetically induced models. Spontaneous models included those animals that naturally developed degenerative disc disease. Conclusion Animal model of intervertebral disc degeneration is an important path for revealing the pathogenesis of human disc degeneration, and play an important role in testing novel interventions. With recent advances in the relevance of animal models and humans, it has a great prospect in study of human disc degeneration.