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 Platelet-rich plasma (PRP) can stimulate intervertebral disc cell proliferation, promote extracellular matrix synthesis, and inhibit annulus fibrosus cell apoptosis. To investigate the effects of autologous PRP on the treatment of the early intervertebral disc degeneration (IDD) so as to provide the experimental basis for its clinical application. Methods Forty-five healthy New Zealand white rabbits (male or female, weighing 2.5-3.0 kg) were randomly divided into the experimental group (n=15), the control group (n=15), and the sham group (n=15). PRP was prepared from the arterial blood of rabbit’s ears of the experimental group with Landesberg’s method. The platelet concentrations in both whole blood and PRP were detected. The rabbit model of early IDD was established by annulus fibrosus puncture (L4, 5, L5, 6) in both the experimental group and the control group; 100 ?L autologous PRP and 100 ?L PBS were injected into the degenerative intervertebral discs respectively after 2 weeks of models creation. In sham group, intervertebral discs were separated and exposed without treatment. The general conditions of the rabbits were observed after building models; at 2 weeks after degeneration, 1 and 2 weeks after intervention, 5 rabbits were selected randomly from each group respectively for MRI observation, histological observation by using HE staining and collagen type II immunohistochemical staining. The signal of lumbar MRI was assessed and the contents of collagen type II were detected. Results The platelet concentration of PRP was about 4.92 times as much as that of the whole blood. All the animals survived to the end of the experiment. At 2 weeks after degeneration, a lower T2 signal was observed in both the experimental group and the control group; the nucleus pulposus cells decreased and extracellular matrix degenerated; and the expression of collagen type II decreased in both the experimental group and control group. The degenerative grade of lumbar MRI in the experimental group and control group were significantly higher than that in the sham group (P lt; 0.05), and the content of collagen type II were significantly lower than that in the sham group (P lt; 0.05). At 1, 2 weeks after intervention, disc degeneration in the experimental group was significantly lower than that in control group (P lt; 0.05), and significant difference was found between experimental group and sham group (P lt; 0.05). The nucleus pulposus cells and chondroid matrix in the experimental group were more than those in the control group, showing slight stromal fibrosis; but the expression of collage type II was significantly higher than that in the control group (P lt; 0.05). Conclusion The disc injection of autologous PRP may terminate or even reverse the progress of rabbit early IDD, which may be associated with the role of multiple growth factors of PRP in regulating cell function, improving the tissue microenvironment, and promoting tissue regeneration.
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.
ObjectiveTo analyze the relationship between the bone mineral density (BMD) and lumbar intervertebral disc degeneration in rhesus macaques by using T1ρ-MRI. MethodsTwenty female rhesus macaques at the age of 10.9 years on average (rang, 4-20 years) were selected. The lumbar intervertebral discs were classified by Pfirrmann grading system and the T1ρ relaxation time (T1ρ value) was examined by using MRI (Philips 1.5 Tesla), and then BMD values of the L4,5 vertebrae and femoral ward's triangle were detected by using Osteocore dual energy X-ray absorptiometry. Finally, the relationship of T1ρ value of the lumbar intervertebral discs and Pfirrmann grading with age, weight, BMD of lumbar vertebrae and femoral ward's triangle was analyzed. ResultsThe BMD values of lumbar vertebrae and femoral ward's triangle were (0.64±0.17) g/cm2 and (0.67±0.19) g/cm2 respectively, showing no significant difference (t=2.893, P=0.128). According to Pfirrmann grading system, there were 7 cases of grade I, 8 cases of grade Ⅱ, and 5 cases of grade Ⅲ at L4,5 intervertebral discs. The T1ρ value of the lumbar intervertebral disc was (104.08±18.65) ms; the T1ρ values of grades I, Ⅱ, and Ⅲ were (121.31±13.44), (104.73±15.01), and (77.41±11.87) ms, respectively. There was a negative correlation between T1ρ value and the age and the BMD of lumbar vertebrae and femoral ward's triangle. There was a positive correlation between Pfirrmann grading and the variables as listed above. Significant negative linear correlation was also observed between T1ρ value and Pfirrmann grading. ConclusionThe T1ρ value is a reliable index when quantifying lumbar intervertebral disc degeneration, and there is a significant positive correlation between BMD and lumbar intervertebral disc degeneration in rhesus macaques.
ObjectiveTo investigate the role of transforming growth factor β1(TGF-β1) and connective tissue growth factor (CTGF) in pathogenesis and progression of human intervertebral disc degeneration by detecting the expressions of these two factors in different degrees of degenerative discs. MethodsThe lumbar intervertebral discs were collected from 33 patients with lumbar disc herniation and 12 patients with lumbar vertebral fracture between November 2012 and April 2013.All samples were observed under the microscope after HE staining,and then were divided into different subgroups according to the degenerative degree.The expressions of TGF-β1 and CTGF were detected by Western blot. ResultsAccording to the pathological features,10 discs were defined as normal discs,10 as mild degenerative discs,9 as moderate degenerative discs,and 16 as severe degenerative discs.The histological observation showed that rounded nucleus pulposus cells with similar size evenly distributed in the cartilage-like matrix,and no hyperplastic collagenous fiber was seen in normal discs;mild degenerative discs characterized by slightly larger nucleus pulposus cells in the matrix,but cells did not decrease,a small quantity of inflammatory cells infiltrated in the matrix,hyperplasia of collagenous fiber was not seen;most of the nucleus pulposus cells became bigger,some showed a bulb form,the number of nucleus pulposus cells was significantly reduced,low grade hyperplasia of collagenous fiber emerged in the matrix,new vessels and inflammatory cells were both found in some specific areas of discs in moderate degenerative discs;there was no nucleus pulposus cells in the matrix of severe degenerative discs,the hyperplasia of collagenous fiber was obvious.The relative expression of TGF-β1 in 3 degeneration discs was significantly higher than that in normal discs (P<0.05),and the expression of TGF-β1 was significantly higher in severe degenerative discs than in moderate and mild degenerative discs (P<0.05),but no significant difference between moderate and mild degenerative discs (P>0.05).The relative expression of CTGF in moderate and severe degeneration discs was significantly higher than that in normal discs (P<0.05);and the expression of CTGF in mild degenerative discs was higher than that in normal discs,but there was no significant difference (P>0.05);and significant difference in CTGF expression was found among 3 degeneration discs (P<0.05). ConclusionThe expressions of TGF-β1 and CTGF are closely related to the degree of human lumbar disc degeneration,these two factors may play an important role in promoting lumbar intervertebral disc degeneration.
ObjectiveTo investigate the influence of endoplasmic reticulum stress (ERS) on smoking-induced nucleus pulposus cells apoptosis and inflammatory response.MethodsBetween October 2016 and October 2018, 25 patients with cervical disc herniation receiving discectomy were collected and divided into smoking group (14 cases) and non-smoking group (11 cases). The baseline data of age, gender, herniated segment, and Pfirrmann grading showed no significant difference between the two groups (P>0.05). The obtained nucelus pulposus tissues were harvested to observe the cell apoptosis via detecting the apoptosis-related proteins (Caspase-3 and PRAP) by TUNEL staining and Western blot test. The nucleus pulposus cells were isolated and cultured with enzyme digestion, of which the third generation cells were used in follow-up experiments. Then, the expressions of inflammatory factors [interleukin 1β (IL-1β) and tumor necrosis factor α (TNF-α)] were detected by ELISA; the nuclear translocation of P65 was monitored by cell immunofluorescence staining. Furthermore, ERS-related proteins (GRP78 and CHOP) were detected by Western blot; and endoplasmic reticulum ultrastructure was observed under transmission electron microscope. To verify the regulatory effect of ERS, cells were pretreated by ERS specific inhibitor (4-PBA), then cell apoptosis and inflammatory response were tested.ResultsThe nucleus pulposus tissue observation showed that the cell apoptotic rate and the expressions of apoptosis-related proteins (Caspase-3 and PARP) were obviously higher in smoking group than in non-smoking group (P<0.05). The nucleus pulposus cells observation indicated that the expressions of the inflammatory factors (IL-1β and TNF-α) and the ERS-related proteins (GRP78 and CHOP) were also higher in smoking group than in non-smoking group (P<0.05). The results of cell immunofluorescence staining further confirmed that smoking stimulated nuclear translocation of P65 in nucleus pulposus cells. The ERS injury was much more serious in smoking group than in non-smoking group. Furthermore, after 4-PBA inhibiting ERS, the expressions of GRP78, CHOP, IL-1β, TNF-α, and P65 were significantly decreased (P<0.05), and flow cytometry results showed that cell apoptotic rate in smoking group was decreased, showing significant difference compared with the non-smoking group (P<0.05).ConclusionSomking can stimulate cell apoptosis and inflammatory response in nucleus pulposus cells via ESR pathway. Suppressing ESR may be a novel target to suspend smoking-induced intervertebral disc degeneration.
ObjectiveTo review the research progress of the role and mechanism of adipokines in intervertebral disc degeneration (IVDD) in recent years.MethodsThe domestic and foreign literature related to adipokines in the process of IVDD was extensively reviewed. The types and functions of adipokines, the role and mechanism in the process of IVDD, and the application prospects of intervertebral disc biotherapy were reviewed.ResultsAs a kind of bioactive substance secreted by adipose tissue, adipokine plays an important role in bone and joint diseases, metabolic diseases, and breast cancer. During IVDD, most adipokines can activate multiple signaling pathways by binding to autoreceptors, cause the proliferation and apoptosis of cells and proinflammatory and anti-inflammatory factors parasecretions in the intervertebral disc, and lead to imbalance of intradiscal metabolism and establishment of the initial inflammatory environment, and finally cause the IVDD.ConclusionAdipokines, as a biologically active substance with metabolic and immunomodulatory functions, play important roles in the occurrence, development, and biological treatment of IVDD.
ObjectiveTo summarize the research progress of hydrogels for the regeneration and repair of degenerative intervertebral disc and to investigate the potential of hydrogels in clinical application.MethodsThe related literature about the role of hydrogels in intervertebral disc degeneration especially for nucleus pulposus was reviewed and analyzed.ResultsHydrogels share similar properties with nucleus pulposus, and it plays an important role in the regeneration and repair of degenerative intervertebral disc, which can be mainly applied in nucleus pulposus prosthesis, hydrogel-based cell therapy, non-cellular therapy, and tissue engineering repair.ConclusionHydrogels are widely used in the regeneration and repair of intervertebral disc, which provides a potential treatment for intervertebral disc degeneration.
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 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.