A novel rabbit disc degeneration model induced by fibronectin fragment / 中华外科杂志

<p><b>OBJECTIVE</b>To establish a novel and useful rabbit model of lumbar disc degeneration using microinjection of fibronectin fragment (Fn-f).</p><p><b>METHODS</b>Thirty-two New Zealand white rabbits underwent injection of N-terminal 30 kDa Fn-f (experimental group) or phosphate buffered saline (PBS) (control group) into the central region of L1-2, L2-3, L3-4, L4-5 discs using a 32-gauge microsyringe. Two rabbits (blank group) with no treatments were sacrificed to examine the proteoglycan synthesis of neucleus pulposus (NP) using (35)S-sulfate incorporation assay. At the 4-, 8-, 12-, and 16-week time points, the discs were examined histologically, radiographically, and with proteoglycan synthesis.</p><p><b>RESULTS</b>Histology demonstrated a progressive loss of the cell numbers in NP and architecture destruction in NP and anulus fibrosus (AF) in Fn-f-injected discs over the 16-week study period. The NP regions in Fn-f-injected discs shrinked distinctly after the 4-week time point, and were not discernible with the inner AF by the 16-week time point. Protoglycan synthesis in Fn-f-injected discs decreased progressively (F = 263.241, P = 0.000). At each time point, the Fn-f-injected discs showed significantly decreased proteoglycan synthesis compared with controls (t = -27.010 - -2.833, P < 0.05). The DHI% of the Fn-f-injected discs at the 4-, 8-, 12-, and 16-week time points were 96.5% ± 1.7%, 85.6% ± 3.8%, 77.2% ± 3.5% and 65.5% ± 5.6%, respectively. Comparing with the DHI% of PBS-injected discs (97.4% ± 1.2%), the Fn-f-injected discs exihibited no significant differences in disc heights at the 4-week time point (P > 0.05), but significant decreases in disc heights at the 8-, 12-, and 16-week time points (t = -21.225 - -10.795, P < 0.01). Apparent anterior osteophytes formed at the 12-week time point and enlarged remarkablely by the 16-week time point in the experimental spines.</p><p><b>CONCLUSIONS</b>Fn-f can induce a progressively degenerative process in rabbit discs which is ethical, cost-effective, reproducible, and consistent with the spontaneous degeneration in human. And it seem to be a novel and useful model for the study of disc degeneration at the molecular level.</p>

The changes of extracellular matrix in adult degenerative nucleus pulposus cells with stiring microcarrier culture system in vitro / 中华外科杂志

<p><b>OBJECTIVE</b>To evaluate the biological effect on the synthesis of the extracellular matrix (ECM) in the cultivation of adult degenerative nucleus pulposus cells using the stiring microcarrier system in vitro.</p><p><b>METHODS</b>Thirty-four specimens were collected after intervertebral fusion operations of the patients with intervertebral disc herniation diseases from September 2005 to May 2009. The specimens were then randomly allocated into 2 groups for in vitro cultivation: monolayer culture group and microcarrier culture group. On the exponential phase, SP-ABC immunohistochemical staining and Western blot quantitative analysis were conducted in the two groups to detect the collagen type I and II. Proteoglycan contents of two groups in different growth phases were detected with (35)S-sulfate incorporation assay.</p><p><b>RESULT</b>The expressions of collagen type I and II in microcarrier culture group were significantly higher than those in monolayer culture group: SP-ABC immunohistochemical staining (collagen type I: 32.5 ± 4.4 vs. 15.2 ± 1.2, t = 2.871, P < 0.01; collagen type II: 43.6 ± 4.1 vs. 23.1 ± 2.2, t = 2.375, P < 0.05); Western blot quantitative analysis (collagen type I: 0.62 ± 0.08 vs. 0.50 ± 0.06, t = 3.327, P < 0.01; collagen type II: 1.46 ± 0.08 vs. 0.86 ± 0.04, t = 2.453, P < 0.05). Nucleus pulposus cells cultivated in stiring microcarrier system showed significantly increased proteoglycan synthesis than monolayer culture group does on both exponential phase and stationary phase (exponential phase: 34 821 ± 312 vs. 21 046 ± 673, t = 2.134, P < 0.05; stationary phase: 45 134 ± 175 vs. 32 193 ± 713, t = 2.801, P < 0.01).</p><p><b>CONCLUSIONS</b>The expression of collagen type I, II and proteoglycan of adult degenerative nucleus pulposus cells are positive regulated by the stiring microcarrier system, which can be used in the mass amplification of the adult degenerative nucleus pulposus cells.</p>

Transplantation of gene-modified nucleus pulposus cells reverses rabbit intervertebral disc degeneration / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Intervertebral disc degeneration is the main cause of low back pain. The purpose of this study was to explore potential methods for reversing the degeneration of lumbar intervertebral discs by transplantation of gene-modified nucleus pulposus cells into rabbit degenerative lumbar intervertebral discs after transfecting rabbit nucleus pulposus cells with adeno-associated virus 2 (AAV2)-mediated connective tissue growth factor (CTGF) and tissue inhibitor of metalloproteinases 1 (TIMP1) genes in vitro.</p><p><b>METHODS</b>Computer tomography (CT)-guided percutaneous annulus fibrosus injury was performed to build degenerative lumbar intervertebral disc models in 60 New Zealand white rabbits. rAAV2-CTGF-IRES-TIMP1-transfected rabbit nucleus pulposus cells were transplanted into degenerative lumbar intervertebral discs (transplantation group), phosphate-buffered saline (PBS) was injected into degenerative lumbar intervertebral discs (degeneration control group) and normal lumbar intervertebral discs served as a blank control group. After 6, 10 and 14 weeks, the disc height index (DHI) and signal intensity in intervertebral discs were observed by X-ray and magnetic resonance imaging (MRI) analysis. The expression of CTGF and TIMP1 in nucleus pulposus tissue was determined by Western blotting analysis, the synthesis efficiency of proteoglycan was determined by a (35)S-sulfate incorporation assay, and the mRNA expression of type II collagen and proteoglycan was detected by RT-PCR.</p><p><b>RESULTS</b>MRI confirmed that degenerative intervertebral discs appeared two weeks after percutaneous puncture. Transgenic nucleus pulposus cell transplantation could retard the rapid deterioration of the DHI. MRI indicated that degenerative intervertebral discs were relieved in the transplantation group compared with the degeneration control group. The expression of collagen II mRNA and proteoglycan mRNA was significantly higher in the transplantation group and the blank control group compared with the degeneration control group (P < 0.05).</p><p><b>CONCLUSIONS</b>CT-guided percutaneous puncture can successfully build rabbit degenerative intervertebral disc models. Both CTGF and TIMP1-transfected cell transplantation helps to maintain disc height, and promotes the biosynthesis of type II collagen and proteoglycan in intervertebral discs, reversing the degeneration of intervertebral discs.</p>

Diagnosis and treatment of disc herniation at cervical vertebra 7-thoracic vertebra 1 (C(7)-T(1)) / 中华外科杂志

<p><b>OBJECTIVE</b>To study the outcome of laminoforaminotomy with posterolateral discectomy for patients with lateral disc herniation at C(7)-T(1).</p><p><b>METHODS</b>From August 2000 to August 2008, 12 patients with lateral disc herniation at C(7)-T(1) underwent posterolateral discectomy were analyzed retrospectively. Neurologic function were evaluated with the Motor Scoring System. Preoperative motor were compared with postoperative one. The unique clinical manifestation, imageology features and intraoperative findings were analyzed.</p><p><b>RESULTS</b>All these twelve patients were lateral type. All the patients showed hand intrinsic muscles atrophy and hand weakness. Nine patients had no paraesthesia. The average follow-up period was 26 months. Postoperative scores were significantly higher than preoperative ones.</p><p><b>CONCLUSIONS</b>Disc herniation at C(7)-T(1) is predominantly lateral type and present C(8) nerve motor deficit (hand intrinsic muscles atrophy and hand weakness) and only minority has paraesthesia in C(8) nerve dermatome. Posterolateral cervical discectomy technique is safe and effective for patients with lateral disc herniation at C(7)-T(1).</p>

Combined expression of CTGF and tissue inhibitor of metalloprotease-1 promotes synthesis of proteoglycan and collagen type II in rhesus monkey lumbar intervertebral disc cells in vitro / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Low back pain has emerged as a widespread disease often caused by intervertebral disc degeneration. This study aimed to establish an in vitro cell culture model of rhesus monkey lumbar intervertebral discs and to investigate the effect of combined connective tissue growth factor (CTGF) and tissue inhibitor of metalloprotease-1 (TIMP-1) expression mediated by adeno-associated virus (AAV) on collagen type II and proteoglycan levels. The purpose of these investigations was to explore potential methods for relieving the degeneration of lumbar intervertebral disc cells.</p><p><b>METHODS</b>Rhesus monkey lumbar intervertebral disc nucleus pulposus cells (NPCs) were isolated by enzyme digestion, cultured, and transduced with rAAV2-CTGF-IRES-TIMP-1, rAAV2-CTGF, or rAAV2-TIMP-1 at a multiplicity of infection (MOI) of 10(6). The expression of collagen type II and proteoglycan was measured using RT-PCR and Western blotting. The synthetic rate of proteoglycan was measured using (35)S incorporation.</p><p><b>RESULTS</b>Rhesus monkey lumbar intervertebral disc NPCs were transduced with rAAV2-CTGF-IRES-TIMP-1, rAAV2-CTGF, and rAAV2-TIMP-1 and the transduced genes were expressed and detected. Compared to the control, CTGF promoted the synthesis of collagen type II and proteoglycan. TIMP-1 showed an enhancing effect on the expression of proteoglycan but no effect on collagen type II. Expression of both genes in rhesus monkey lumbar intervertebral disc NPCs significantly enhances the synthesis of proteoglycan and collagen type II.</p><p><b>CONCLUSIONS</b>Single gene transduction of CTGF or TIMP-1 can enhanced synthesis of proteoglycan. CTGF expression can also enhance collagen type II protein synthesis. Combined transduction of both CTGF and TIMP1 can significantly promote the expression of proteoglycan and collagen type II to levels greater than transduction of a single gene alone. Our study provides a good basis for multi-gene therapy to treat lumbar intervertebral disc degeneration.</p>

Outcomes of posterior C(1-2) fusion for atlantoaxial instability or dislocation using pedicle screws of atlas and axis / 中华外科杂志

<p><b>OBJECTIVE</b>To retrospectively analyze and evaluate the results of treatment for atlantoaxial instability or dislocation employing pedicle screws of atlas and axis.</p><p><b>METHODS</b>Thirty-one patients (23 male and 8 female) with atlantoaxial instability or dislocation were stabilized using pedicle screws of atlas and axis between May 2005 to January 2008. The patients ranged in age from 17 to 67 years (mean 43.5 years). Patients consisted of chronic odontoid fracture in 17, Os odontoideum in 8, fresh odontoid fracture in 4, transverse ligament rupture in 1, rheumatoid arthritis in 1. Clinical features included neck pain in 31; restricted neck movement in 28, varying degrees of spastic quadriparesis in 19. All patients underwent posterior C(1) to C(2) pedicle screw fixation. Operative time, intraoperative blood loss, complications were recorded, neurological and radiographic studies were carried.</p><p><b>RESULTS</b>Mean follow-up time was 13 months. Operative time averaged 2.5 h. Mean intraoperative blood loss was 300 ml. A patient had postoperative wound infection and was treated conservatively with antibiotics and local wound care. A patient developed pulmonary artery embolism and got well with anticoagulation. Satisfactory stability was achieved in all cases with no vascular and C(2) neuralgia. Average JOA score in 19 cases increased at final follow-up (P < 0.01). Solid fusion was achieved in 29 cases, fusion rate was 93.6%.</p><p><b>CONCLUSIONS</b>Stabilization of atlantoaxial complex via pedicle screws of atlas and axis has advantages of intraoperative restoration, easier placement of screw, solid fixation. It is a safe and effective treatment modality for posterior C(1-2) fusion.</p>

Clinical investigation of high-intensity zone in anterior annulus fibrosus of lumbar disc: compared with high-intensity zone in posterior annulus fibrosus / 中华外科杂志

<p><b>OBJECTIVE</b>To explore the prevalence, distribution and clinical significance of high-intensity zone (HIZ) in anterior annulus fibrosus (AF) in comparison with HIZ in posterior AF of lumbar disc.</p><p><b>METHODS</b>According to the diagnosis and location of HIZ, 610 lumbar magnetic resonance images with entire clinical materials were divided into control group (without HIZ), anterior AF group (HIZ), posterior AF group (HIZ) and anterior & posterior (AP) AF group (HIZ). The incidence of HIZ was summarized. The clinical data, such as male/female ratio, age, and body weight, prevalence of low back pain (LBP) and distribution of HIZ, were compared and analyzed between the groups.</p><p><b>RESULTS</b>Three hundred and fifteen cases shown no HIZ (51.6%), 95 cases presented HIZ in anterior AF (15.6%, 119 discs), 159 cases presented HIZ in posterior AF (26.1%, 189 discs) and 41 cases presented HIZs in both anterior and posterior AF (6.7%, 96 discs). There was significant difference between the prevalence of HIZ in anterior AF and that in posterior AF (P < 0.01). The male/female ratio and body weight of each groups showed no difference (P > 0.05), and the age was proved to be statistically different between four groups (P < 0.01, control group < posterior AF group < AP AF group < anterior AF group). HIZs in anterior AF often occurred at L(1,2)-L(4,5), whereas, they usually developed at L(3,4)-L(5)S(1) in posterior AF. The incidence of LBP in control group, anterior AF group, posterior AF group, AP AF group were 40.0%, 52.6%, 55.4% and 65.8%, respectively. The LBP prevalence of control group was lower than that of other three groups (P < 0.05), and the prevalence of last three groups showed no difference (P > 0.05).</p><p><b>CONCLUSIONS</b>Compared with HIZ in posterior AF, the HIZ in anterior AF of lumbar disc has a lower prevalence, often develops in elder patients and in upper motion segments. It also indicates an obvious relation to LBP as the former.</p>

A model of lumbar disc degeneration on the early stage in rhesus monkey with minimally invasive technique / 中华外科杂志

<p><b>OBJECTIVE</b>To establish a novel model of lumbar disc degeneration on the early stage in the rhesus monkey using percutaneous needle puncture guided by CT.</p><p><b>METHODS</b>(1) Thirteen rhesus monkeys aged from 4 to 7 years, female 7 and male 6 were selected for establishing a model of the early stage of lumbar disc degeneration. (2)13 monkeys, 91 discs were divided into 3 groups: 64 discs from L1/2 to L5/6 were percutaneous punctured with a needle 20G as experimental group and 1 disc with a needle 15G as puncture control group and 26 discs were not be punctured from L6,7 to L7-S1 as control group. (3) Lumbar disc localization for needle puncture was guided by CT. All discs were examined by MRI, the HE, Masson's trichrome, Safranine-O and immunohistochemical staining of type II collagen before disc puncture and after puncture at 4, 8 and 12 weeks.</p><p><b>RESULTS</b>MRI: (1) Experimental group: Pfirmann's Grade I was shown at postoperation 4, 8 and 12 weeks; (2) Puncture control group: Grade III was shown at postoperation 4 weeks and Grade IV at 8 weeks; (3) CONTROL GROUP: Grade I was shown at postoperation 4, 8 and 12 weeks. Histological examination: (1) In experimental group, there was no any change at postoperation 4 weeks, and the cell population of the nucleus was decreased at 8 weeks and more decreased at 12 weeks in HE. (2) There was no any change at postoperation 4 weeks, the clefts among the lamellae of the annulus fibrosus (AF) were shown at 8 weeks and more wider of the clefts of AF at 12 weeks in Masson's trichrome. (3) No any change was shown at postoperation 4 weeks, proteoglycan were progressively decreased at 8 and 12 weeks in Safranine-O. (4) No statistically significant difference in positive rate was observed at 4 and 8 weeks compared with control group in immunohistochemical staining of type II collagen. There was statistical difference at 12 weeks compared with control group (P<0.05). In puncture control group postoperation 8 weeks, the morphology of cell of nucleus pulposus was not clear in HE. The wider clefts of lamellae of the AF were shown in Masson's trichrome. The proteoglycan was obviously decreased in Safranine-O. Immunohistochemical staining collagen II synthesized was decreased. In normal control group, no any change was shown at 4, 8 and 12 weeks.</p><p><b>CONCLUSIONS</b>The degeneration of lumbar intervertebral disc on the early stage could be induced by the percutaneous needle puncture (20G) to the annulus fibrosus. The assessment of disc degeneration on early stage is not shown on MRI and only confirmed by histological examination.</p>

Constructing adeno-associated virus-TGFbeta3 and comparing its biological effect on proteoglycan synthesis in dedifferentiated nucleus pulpous cells with adenovirus-TGFbeta1 / 中国医学科学杂志(英文版)

<p><b>OBJECTIVE</b>To construct adeno-associated virus (AAV) expression system for transforming growth factor beta3 (TGFbeta3 ) and detect its biological effect on proteoglycan synthesis of the earlier and later dedifferentiated rabbit lumbar disc nucleus pulpous (NP) cells, which was compared with that of adenovirus (AV) expression system for TGFbeta1.</p><p><b>METHODS</b>TGFbeta3 gene was obtained using PCR. Its upstream contained restriction enzyme site Kpn I, and its downstream contained restriction enzyme site Sal I. Using the restriction enzyme sites of PCR product of TGFbeta3 and the corresponding multiple cloning site (MCS) in plasmid AAV, TGFbeta3 was subcloned into AAV. The recombinant plasmid AAV-TGFbeta3 was transfected into H293 cells with Lipofectamine 2000, and the expression of TGFbeta3 gene was detected using immunofluorescent analysis. After AAV-TGFbeta3 virus particle with infectious activity was packaged, TGFbeta3 expression in NP cells was detected by immunoblotting, and its biological effect on proteoglycan synthesis was detected by antonopulos method and compared with that of AV-TGFbeta1 in the earlier and later dedifferentiated NP cells.</p><p><b>RESULTS</b>For the earlier dedifferentiated NP cells, AAV-TGFbeta3 slowly and stably enhanced proteoglycan synthesis, but AV-TGFbeta1 rapidly and transiently enhanced its synthesis. For the later dedifferentiated NP cells, AAV-TGFbeta3 stably enhanced proteoglycan synthesis, but AV-TGFbeta1 inhibited its synthesis.</p><p><b>CONCLUSION</b>AAV expression system can mediate TGFbeta3 gene to be expressed stably, and AAV-TGFbeta3 can enhance proteoglycan synthesis of the earlier and later dedifferentiated NP cells.</p>

Gene expression of collagen types IX and X in the lumbar disc / 中华创伤杂志(英文版)

<p><b>OBJECTIVE</b>To study gene expression of collagen types IX and X in human lumbar intervertebral discs during aging and degeneration and to explore the role of collagen types IX and X in disc degeneration.</p><p><b>METHODS</b>Fetal, adult and pathologic specimens were subjected to in situ hybridization with cDNA probes to investigate mRNA-expressions of types IX and X collagen gene.</p><p><b>RESULTS</b>In fetal intervertebral discs, positive mRNA hybridization signals of type IX collagen were concentrated in the nucleus pulposus and the inner layer of anulus fibrosus. Interstitial matrix of the nucleus pulposus also showed positive type X collagen staining. Positive mRNA hybridization signals of types IX and X were not detected in the middle and outer layers of anulus fibrosus. In adult specimens, expression of type IX collagen mRNA was markedly decreased. No hybridization signals of type X collagen was observed. As for pathological specimens, there was no gene expression of type IX collagen. In severe degenerated discs from adults, there were focal positive expressions of type X collagen.</p><p><b>CONCLUSIONS</b>Obvious changes of collagen gene expression occur with aging. Expression of type IX collagen decreases in adult and pathological discs. Results of type X collagen expression suggest that type X collagen is expressed only in older adult and senile discs (i.e., when disc degeneration has already reached a terminal stage), indicating the terminal stage of degeneration.</p>