Application of a novel porous tantalum implant in rabbit anterior lumbar spine fusion model: in vitro and in vivo experiments.

BACKGROUND: Some porous materials have been developed to enhance biologic fusion of the implants to bone in spine fusion surgeries. However, there are several inherent limitations. In this study, a novel biomedical porous tantalum was applied to in vitro and in vivo experiments to test its biocompatibility and osteocompatibility. METHODS: Bone marrow-derived mesenchymal stem cells (BMSCs) were cultured on porous tantalum implant. Scanning electron microscope (SEM) and Cell Counting Kit-8 assay were used to evaluate the cell toxicity and biocompatibility. Twenty-four rabbits were performed discectomy only (control group), discectomy with autologous bone implanted (autograft group), and discectomy with porous tantalum implanted (tantalum group) at 3 levels: L3-L4, L4-L5, and L5-L6 in random order. All the 24 rabbits were randomly sacrificed at the different post-operative times (2, 4, 6, and 12 months; n = 6 at each time point). Histologic examination and micro-computed tomography scans were done to evaluate the fusion process. Comparison of fusion index scores between groups was analyzed using one-way analysis of variance. Other comparisons of numerical variables between groups were made by Student t test. RESULTS: All rabbits survived and recovered without any symptoms of nerve injury. Radiographic fusion index scores at 12 months post-operatively between autograft and tantalum groups showed no significant difference (2.89 ±â€Š0.32 vs. 2.83 ±â€Š0.38, F = 244.60, P = 0.709). Cell Counting Kit-8 assay showed no significant difference of absorbance values between the leaching liquor group and control group (1.25 ±â€Š0.06 vs. 1.23 ±â€Š0.04, t = -0.644, P = 0.545), which indicated the BMSC proliferation without toxicity. SEM images showed that these cells had irregular shapes with long spindles adhered to the surface of tantalum implant. No implant degradation, wear debris, or osteolysis was observed. Histologic results showed solid fusion in the porous tantalum and autologous bone implanted intervertebral spaces. CONCLUSION: This novel porous tantalum implant showed a good biocompatibility and osteocompatibility, which could be a valid biomaterial for interbody fusion cages.

One-stage posterior approach for treating multilevel noncontiguous thoracic and lumbar spinal tuberculosis.

OBJECTIVES: Multilevel noncontiguous thoracic and lumbar spinal tuberculosis (MNST) is a relatively rare entity. The objective of this retrospective study was to investigate whether a technique involving a one-stage posterior debridement and decompression, combined with an intervertebral fusion and posterior instrumentation, is effective for treating MNST. METHODS: Thirteen patients, with an average age of 40.69 (18-67) years, who had MNST and were surgically treated in our department from January 2008 to October 2013, were reviewed. RESULTS: The average follow-up time was 37.54 ± 10.49 (19-58) months. The mean Cobb angle range was 15.69° ± 00A09.09° (-3° to 33°). The mean erythrocyte sedimentation rate (ESR) was 47.69 ± 9.30 mm/h (range 30-62 mm/h) before the operation. Neurological deficits were evaluated using the Frankel grade system. The mean Cobb angle decreased to 6.92° ± 3.93° postoperatively. Three months after the operation, the Cobb angle was 7.54° ± 4.35°, and the average ESR was 10.38 ± 4.54 mm/h that was normal for all cases in this retrospective observational study. Solid fusion was achieved in all cases. No severe complications occurred. CONCLUSIONS: The study demonstrated that a one-stage posterior debridement and decompression, combined with an intervertebral fusion and posterior instrumentation, was effective for treating MNST.

[Clincial effect of 3D printing-assisted minimal invasive surgery through a small incision lateral to the rectus abdominis for pelvic fracture].

OBJECTIVE: To evaluate the clinical effect of 3D printing-assisted minimal invasive surgery on pelvic fracture by plate internal fixation through a small incision lateral to the rectus abdominis. METHODS: This retrospective study was conducted among 50 patients with pelvic fracture undergoing anteromedial plate internal fixation between September, 2013 and June, 2015. Thin-layer computed tomography scan data of the patients were input into Mimics software in DICOM format for 3D editing and virtual surgery before the operation. The pelvic model was created by 3D printing. Simulated operation was performed to design the optimum location of the plate screw, prelflex of the plate, screw length measurement and screwing approach. Diaplasis and internal fixation were performed through the extraperitoneal space with a small incision lateral to the rectus abdominis. Matta standard was employed for diaplasis evaluation, and Majeed assessment was used for function evaluation 6 months after the operation. RESULTS: According to Matta standard, excellent and good diaplases were achieved in 96% of the cases, as compared with 94% according to Majeed assessment. Radiographic examination showed a good consistency between the internal fixation and simulated operation. No screw entry into the hip joint cavity occurred in these cases. The mean operation time was 127 min in these cases with a mean intraoperative blood loss of 728 mL and a mean incision length of 8.4 cm. Based on the postoperative VAS score, 12 patients reported severe pain, 28 reported moderate pain and 10 reported mild pain. All the patients were advised for early functional exercise after the operation and clinical healing was achieved in a mean of 8 weeks. CONCLUSIONS: 3D printing with simulated operation can improve the accuracy and safety of the operation. Preoperative simulation of plate preflex and screw length measurement can shorten the operation time. A small incision lateral to the rectus abdominis allows minimally invasive operation for pelvic fractures.

Albendazole and Corticosteroids for the Treatment of Solitary Cysticercus Granuloma: A Network Meta-analysis.

BACKGROUND: Solitary cysticercus granuloma (SCG) is the commonest form of neurocysticercosis in the Indian subcontinent and in travelers. Several different treatment options exist for SCG. We conducted a Bayesian network meta-analysis of randomized clinical trials (RCTs) to identify the best treatment option to prevent seizure recurrence and promote lesion resolution for patients with SCG. METHODS AND PRINCIPAL FINDINGS: PubMed, EMBASE and the Cochrane Library databases (up to June 1, 2015) were searched for RCTs that compared any anthelmintics or corticosteroids, alone or in combination, with placebo or head to head and reported on seizure recurrence and lesion resolution in patients with SCG. A total of 14 RCTs (1277 patients) were included in the quantitative analysis focusing on four different treatment options. A Bayesian network model computing odds ratios (OR) with 95% credible intervals (CrI) and probability of being best (Pbest) was used to compare all interventions simultaneously. Albendazole and corticosteroids combination therapy was the only regimen that significantly decreased the risk of seizure recurrence compared with conservative treatment (OR 0.32, 95% CrI 0.10-0.93, Pbest 73.3%). Albendazole and corticosteroids alone or in combination were all efficacious in hastening granuloma resolution, but the combined therapy remained the best option based on probability analysis (OR 3.05, 95% CrI 1.24-7.95, Pbest 53.9%). The superiority of the combination therapy changed little in RCTs with different follow-up durations and in sensitivity analyses. The limitations of this study include high risk of bias and short follow-up duration in most studies. CONCLUSIONS: Dual therapy of albendazole and corticosteroids was the most efficacious regimen that could prevent seizure recurrence and promote lesion resolution in a follow-up period of around one year. It should be recommended for the management of SCG until more high-quality evidence is available.

Regulation of bone formation by baicalein via the mTORC1 pathway.

Osteoporosis is a systemic skeletal disease that is characterized by low bone density and microarchitectural deterioration of bone tissue. The increasing prevalence of osteoporosis has attracted much attention. In this study, MC3T3-E1 pre-osteoblasts were treated with the natural compound, baicalein (0.1 µmol/L, 1 µmol/L, 10 µmol/L), to stimulate differentiation over a 14-day period. In addition, a canonical ovariectomized (OVX) mouse model was used to investigate the effect of 3-month baicalein treatment (10 mg/kg per day) in preventing postmenopausal osteoporosis. In vitro, we found that baicalein induced activation of alkaline phosphatase, stimulated the mammalian target of rapamycin complex 1 (mTORC1) signaling pathway, and induced expression of osteoblast differentiation markers, ie, osteocalcin, osterix, collagen Iα1, and runt-related transcription factor 2 (RUNX2), in osteoblasts. In vivo, several bone parameters, including trabecular thickness, trabecular bone mineral density, and trabecular number, in the distal femoral metaphysis were significantly increased in OVX mice treated intragastrically with baicalein for 3 months compared with OVX mice that were not treated with baicalein. We also found that expression of osteocalcin and RUNX2 was decreased in primary ossified tissue from the OVX group, and baicalein increased the levels of osteocalcin and RUNX2 in OVX mice. These data suggest that baicalein can stimulate MC3T3-E1 cells to differentiate into osteoblasts via activation of the mTORC1 signaling pathway, which includes protein kinases and transcription factors such as P-4E/BP1 and P-S6K1.

Enhancement of the synthesis of n-3 PUFAs in fat-1 transgenic mice inhibits mTORC1 signalling and delays surgically induced osteoarthritis in comparison with wild-type mice.

BACKGROUND: An exogenous supplement of n-3 polyunsaturated fatty acids (PUFAs) has been reported to prevent osteoarthritis (OA) through undefined mechanisms. OBJECTIVE: This study investigated the effect of alterations in the composition of endogenous PUFAs on OA, and associations of PUFAs with mammalian target of rapamycin complex 1 (mTORC1) signalling, a critical autophagy pathway in fat-1 transgenic (TG) mice. METHODS: fat-1 TG and wild-type mice were used to create an OA model by resecting the medial meniscus. The composition of the endogenous PUFAs in mouse tissues was analysed by gas chromatography, and the incidence of OA was evaluated by micro-computed tomography (micro-CT), scanning electron microscopy and histological methods. Additionally, primary chondrocytes were isolated and cultured. The effect of exogenous and endogenous PUFAs on mTORC1 activity and autophagy in chondrocytes was assessed. RESULTS: The composition of endogenous PUFAs of TG mice was optimised both by increased n-3 PUFAs and decreased n-6 PUFAs, which significantly alleviated the articular cartilage destruction and osteophytosis in the OA model (p<0.01), decreased protein expression of matrix metalloproteinase-13 (MMP-13) and ADAMTS-5 (a disintegrin and metalloproteinase with thrombospondin motifs) in the articular cartilage (p<0.01) and reduced chondrocyte number and loss of cartilage extracellular matrix. Both exogenous and endogenous n-3 PUFAs downregulated mTORC1 activity and promoted autophagy in articular chondrocytes. Conversely, mTORC1 pathway activation suppressed autophagy in articular chondrocytes. CONCLUSIONS: Enhancement of the synthesis of endogenous n-3 PUFAs from n-6 PUFAs can delay the incidence of OA, probably through inhibition of mTORC1, promotion of autophagy and cell survival in cartilage chondrocytes. Future investigation into the role of the endogenous n-6/n-3 PUFAs composition in OA prevention and treatment is warranted.

[Preliminary study for classification of spino-pelvic sagittal alignment in adult volunteers].

OBJECTIVE: To investigate the feasibility of the classification of the spino-pelvic sagittal alignment in adluts according to lumbar lordosis (LL) and inflection point (IP). METHODS: Whole spine, standing radiographs of 223 adult volunteers were taken from July to August in 2011 .There were 111 cases(56 female and 55 male) enrolled in the study based on the inclusion criteria. The pelvic and spinal parameters, including thoracic kyphosis(TK), thoracolumbar kyphosis(TLK), LL, sacral slope(SS), pelvic tilt(PT), pelvic incidence(PI), intervertebral endplate angle, sagittal vertical axis (SVA), spino-sacral angle (SSA) and IP were measured. The spino-pelvic sagittal alignment were classified in to 3 types according to LL and IP. Type I: LL > -40°, IP located below L2 ∼ 3; Type II: -60° ≤ LL ≤ -40°, IP located in L1 ∼ 2 or T12 ∼ L1; Type III: LL < -60°, P located above T11 ∼ 12. Pearson correlation analysis was used to test the correlation between the variables. The parameters in each type were compared by oneway-ANOVA respectively,then additional multiple comparisons were performed. RESULTS: The mean value of LL was -49° ± 10°, TK was 36° ± 7°, TLK was 6° ± 7°, PT was 11° ± 7°, SS was 34° ± 8°, PI was 45° ± 9°, SSA was 127° ± 9° and SVA was (-2.7 ± 22.8)mm, respectively. Only LL had significant statistical correlation with all the other parameters. Negative correlation presented between LL and TK, PI, SS, SSA (r = -0.387, -0.536, -0.858, -0.801,P < 0.05). Positive correlation presented between LL and TLK, SVA, PT (r = 0.319, 0.296, 0.262, P < 0.05). All the volunteers were classified into the 3 types: Type I1 9 cases, Type II 75 cases,Type III 17 cases. Oneway-ANOVA results showed statistical difference in LL, TK, TLK, PT, SS, PI, SSA, SVA among the 3 types, (F = 164.559, 7.431, 14.099, 4.217, 53.856, 6.252, 35.995, 8.626, P < 0.05 ). Multiple comparisons showed that LL, SS, SSA, PI had statistical difference between each two types comparison (P < 0.05). CONCLUSIONS: LL is the central parameter of the spino-pelvic sagittal balance. The patterns of the spino-pelvic sagittal alignment in adults could be classified into three types, according to LL and IP. The classification could describe the morphological differences and balance of the spino-pelvic sagittal alignment.

Endogenous n-3 polyunsaturated fatty acids (PUFAs) mitigate ovariectomy-induced bone loss by attenuating bone marrow adipogenesis in FAT1 transgenic mice.

AIM: To investigate the effect of endogenous n-3 polyunsaturated fatty acids (PUFAs) on bone marrow adipogenesis under osteoporosis conditions. METHODS: A mouse osteoporosis model overexpressing the FAT1 gene from Caenorhabditis elegans and converting n-6 PUFAs to n-3 PUFAs endogenously was used. RESULTS: The mice presented significantly lower bone marrow adiposity (adipocyte volume/tissue volume, mean adipocyte number) but increased the bone parameters (bone mineral density, bone mineral content, bone volume/total volume) in the distal femoral metaphysis. CONCLUSION: Endogenous n-3 PUFAs protect bone marrow adipogenesis, which provides a novel drug target.

[Preliminary clinical results of endoscopic assisted anterior lumbar interbody fusion].

OBJECTIVE: To summarize the experiences of endoscopic assisted anterior lumbar interbody fusion (ALIF) with self-locking cage via retroperitoneal approach through small incision lateral to abdominal rectus. METHODS: There were 47 cases of endoscopic assisted ALIF from April 2010 to April 2012 were reviewed retrospectively, including 28 male and 19 female patients whose age ranged from 39 to 65 years, averaged of (48 ± 11) years. Of 47 cases, 17 cases were founded instability in lumbar spine, 16 cases of discogenetic low back pain, 7 cases of degenerative spondylolithesis, and 7 cases of recurrent disc herniation. The level involved included 7 cases at L3-4 level, 33 cases at L4-5 level, 7 cases at L5-S1. X-ray and/or 3D CT scan were done in each patient at post-operative day 4, 1 month, 3 months, and 6 months. The height and angle of disc space, angle of lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS) were recorded and measured, as well as length of incision, operation time, blood loss, complications and ratio of bone graft fusion. The clinical outcomes were evaluated by Oswestry disability index (ODI) and visual analogue scale (VAS). RESULTS: Average length of incision was (6.2 ± 0.8)cm (5.3-7.8 cm) , average blood loss was (81 ± 20)ml (50-150 ml) , mean operation time was (96 ± 10)minutes (65-122 minutes) . There were significant improvement of ODI(48% ± 10% vs. 14% ± 5%), the VAS of back pain(6.3 ± 1.1 vs.0.7 ± 0.7) and VAS of leg pain(3.4 ± 2.1 vs.0.6 ± 0.6) during preoperative and postoperation last follow-up (t = 20.78, 25.92 and 8.74, P = 0.000). The disc height of operative segments were all recovered significantly (F = 18.971, P = 0.000) postoperatively, from preoperative (10.3 ± 2.4)mm to postoperative (12.6 ± 2.1)mm. For complications, 5 cases had peritoneum tear, 19 cases had bone donor site pain, 14 cases had abdominal distension and 5 cases had lower limb paraesthesia, which were all treated with supportive managements. Bony intervertebral fusion was obtained in all cases in 6 months postoperatively. CONCLUSIONS: The advantages of endoscopic assisted ALIF with self-locking cage via retroperitoneal approach are less damage, rapid recovery, and less blood loss. Comparing with traditional ALIF procedure, the view of operative field is also improved.

Establishing a disc degeneration model using computed tomography-guided percutaneous puncture technique in the rabbit.

BACKGROUND: Various animal models have been developed to investigate the complex mechanisms leading to intervertebral disc disorders and to evaluate the different therapeutic options. The needle puncture technique is commonly used to induce intervertebral degeneration in animal models. The present study aimed to establish a rabbit model of intervertebral disc degeneration using a simple, minimally invasive procedure. METHODS AND MATERIALS: The animal model was created in the rabbit using computed tomography-guided percutaneous puncture technology. An 18-gauge needle was used to induce a disc injury with a 5-mm puncture depth. Radiographic, histologic, and biochemical analyses and magnetic resonance imaging were performed to assess the consequent disc degeneration. RESULTS: Significant disc space narrowing was observed as early as 4 wk, and osteophytes were formed at 12 wk after puncture. The magnetic resonance imaging assessment demonstrated a progressive loss of T2-weighted signal intensity at the stabbed discs throughout the 12-wk period. The histologic analysis showed a progressive loss of the normal architecture from 4 wk to the end point. The biochemical assays suggested that the expression of proteoglycan decreased progressively with increasing time. CONCLUSIONS: A simple, but minimally invasive, intervertebral disc degeneration model was established successfully using computed tomography-guided percutaneous puncture technology in the rabbit. The puncture procedure can be performed with minimal damage and handling of the other structures, ensuring a uniform reproducible disc degeneration model.

Could heterotopic ossification be prevented by varying dietary n-3/n-6 polyunsaturated fatty acid ratio: a novel perspective to its treatment?

Heterotopic ossification (HO) is a common complication following with musculoskeletal trauma and surgical procedures. It usually decreases joint mobility and eventually causes loss of joint function. Despite nonsteroidal anti-inflammatory drugs (NSAIDs), the inhibitor of cyclooxygenase(COX), have been proven to prevent HO effectively via prostaglandin E2 synthesis regulation and modulation of tissue responsiveness to pro-inflammatory signaling, HO prevention is still a matter of debate for clinicians to avoid the side effect of NSAIDs. Interestingly, it is suggested that PGE2 production and pro-inflammatory microenvironment in body could be modified by varying the ratio of the precursor fatty acids in the diet. On account of the effect of dietary (n-6)/(n-3) PUFAs ratio on both COX metabolism and pro-inflammatory cytokines mediated biological responsiveness, we hypothesized lowering dietary (n-6)/(n-3) PUFAs ratio may not only directly reduce the substrate of COX-2 and COX-2 activity, but also partially ameliorate tissue inflammatory responsiveness to cytokines correlated with HO development,exerting an inhibitory effect on PGE2 synthesis to prevent HO formation. The negative role of lowering dietary (n-6)/(n-3) PUFAs ratio on angiogenesis, cytokines-induced apoptosis, inflammatory responsiveness and osteogenesis could also contribute to its action on HO development. If our hypothesis is proved to be corrected, it could be an innovative method to treat HO.

Risedronate inhibits bone marrow mesenchymal stem cell adipogenesis and switches RANKL/OPG ratio to impair osteoclast differentiation.

BACKGROUND: Osteoporosis is accompanied by an increase in bone marrow adipose tissue. Bone marrow adipogenesis has emerged as a therapeutic target for prevention of bone loss. Amino-bisphosphonates have been widely used for treatment of osteoporosis, but the mechanism through which amino-bisphosphonates inhibit osteoporosis remains unclear. The purpose of this study is to investigate the effects of bisphosphonates on bone marrow adipogenesis and the pro-osteoclastic factors produced by adipocytes in bone marrow microenvironment. MATERIALS AND METHODS: Human mesenchymal stem cells were obtained and purified from six volunteer donors. Each sample of cells was treated by increasing concentrations of risedronate with or without adipogenic induction for 14 d, and then droplets of the differentiated adipocytes were analyzed. The level of receptor activator of nuclear factor-κB ligand and osteoprotegerin, as well as pro-osteoclastic inflammatory factors interleukin-1, interleukin-6, and tumor necrosis factor α produced by adipocytes were evaluated by Western blot and ELISA assay. Moreover, the effect of risedronate on the activity of mammalian target of rapamycin complex 1, a key Ser/Thr kinase for initiation of adipocyte differentiation, was investigated. RESULTS: Risedronate not only dose-dependently inhibited the bone marrow adipogenesis from human mesenchymal stem cells but also suppressed receptor activator of nuclear factor-κB ligand, not osteoprotegerin, expression in differentiated adipocytes, as well as pro-osteoclastic inflammatory factors. Furthermore, the activity of mammalian target of rapamycin complex 1 was suppressed by risedronate. CONCLUSION: Our findings that risedronate influences the crosstalk between bone marrow adipocyte-osteoclast represent a novel mechanism for the anti-osteoporotic effects of risedronate.

[The use of anterior cervical discectomy and fusion with self-locking cages to treat multi-segmental cervical myelopathy].

OBJECTIVE: To investigate the use of anterior cervical discectomy and fusion with self-locking cages to treat multi-segmental cervical myelopathy. METHODS: From April 2008 to March 2010, anterior cervical discectomy and fusion with self-locking cages were performed on 45 patients who suffered from multi-segmental cervical myelopathy, among of them there were 23 male and 22 female, aged from 32 to 67 years (average 53 years). Recording the Japanese Orthopedic Association (JOA) scores and SF-36 scores in the protocol time point, in order to investigate the clinical outcome, meanwhile, accumulating the pre-operation and postoperation X-ray films of cervical spine for measuring the height of intervertebral space, whole curvature of cervical spine and the rate of fusion by repeated measures analysis of variance. RESULTS: The mean follow-up time was 28.4 months (24 - 35 months). JOA scores ascended from preoperative 6.5 ± 3.1 to postoperative 13.4 ± 1.7 (F = 17.84, P = 0.001), the 7 scores of SF-36 improved significantly after operation (t = 1.151 - 12.207, P < 0.05), but mental health not. The fineness rate was 91.1%. Height of disc space ascended from preoperative (5.5 ± 1.8) mm to postoperative (8.3 ± 0.8) mm (F = 11.71, P = 0.043), globle curvature of cervical spine ascended from preoperative 5° ± 7° to postoperative 10° ± 14° (F = 234.53, P = 0.000), the change of the two index was significantly, respectively. Fat necrosis in one case and hematoma in another case at the bone donor-site were found, both of the two cases were cured by physiotherapy. All of the 45 cases (111 segments) achieved bone fusion. CONCLUSION: The use of anterior cervical discectomy and fusion with self-locking cages to treat multi-segmental cervical myelopathy possess many advantages as follows: satisfactory clinical outcome, minimally invasive, higher fusion rate, higher orthopaedic ability.

Intra-articular lentivirus-mediated insertion of the fat-1 gene ameliorates osteoarthritis.

Osteoarthritis (OA) is a gradually progressive degenerative disease characterized by gradual inflammatory loss of articular cartilage caused by increased proteolytic catabolism, mediated by interleukin-1 (IL-1), tumor necrosis factor α (TNF-α), matrix metalloproteinase (MMPs), aggrecanases and other proteinases, and reduced anabolism of cartilage components, contributed by interleukin-4 (IL-4), interleukin-10 (IL-10), insulin-like growth factor 1 (IGF-1), transforming growth factor ß (TGF-ß), and bone morphogenetic proteins (BMPs). Substantial studies showed n-3 polyunsaturated fatty acids (n-3 PUFAs) exhibit a powerful anti-inflammatory effects in and ex vivo through reducing the production of IL-1 and TNF-α and increasing the expression of IL-4, IL-10, TGF-ß and IGF-1 in OA. Meanwhile, more convincing results are observed in the fat-1 transgenic mice, which are exogenously inserted in a fat-1 gene from Caenorhabditis elegans, which can endogenously convert n-6 polyunsaturated fatty acids (n-6 PUFAs) to n-3 PUFAs. Taken together, it has long been realized that dietary supplementation with fish oils that are plentiful of n-3 PUFAs can bring benefits in the treatment of osteoarthritis. Previously two phase I human studies based on in vitro transfer of the cDNA via lentivirus to arthritic joints have confirmed its feasibility and safety in human subjects. Consequently, we hypothesis that directly infect the chondrocytes and synoviocytes with lentivirus carrying the fat-1 gene could be a well therapeutic strategy for OA in humans.

[Establishment of a rabbit model of lumbar intervertebral disc degeneration via the paraspinal approach].

OBJECTIVE: To establish a rabbit model of intervertebral disc degeneration by puncturing the anulus fibrosus through an approach between the longissimus dorsi muscle and obliquus externus abdominis. METHODS: The L(4/5) and L(5/6) intervetebral discs of 6 New Zealand white rabbits were punctured by an 18-gauge pin in the anterolateral annular fibrosus through an approach between the longissimus dorsi muscle and the obliquus externus abdominis with the right transverse processes of L(5) and L(6) resected; the L(2/3) discs were used as the control without exposure or needle stab, and the L(3/4) discs were subjected to sham operation with the discs exposed but not punctured after resecting the right transverse process of L(4). X-ray and magnetic resonance imaging (MRI) were performed preoperatively and at the 4th week after puncture. At 4 weeks after the operation, histological and immunohistochemical analyses of the discs were carried out. RESULTS: X-ray of the punctured discs at 4 weeks after the operation presented a significant decrease of disc height, osteophytosis formation, and end-plate stiffness; an obvious decrease of signal intensity on T(2)-weighted images was found in the puncture group but not in the control or sham-operated groups. Gross morphological inspection showed atrophy of the nucleus pulposus, which became loose, soft, and fragile with a light yellow color. Histological and immunohistochemical analyses showed a significant decrease of notochordal cells and type II collagen in the nucleus pulposus in the puncture group as compared to the control and sham-operated groups. CONCLUSION: Puncture through the approach between the longissimus dorsi muscle and the obliquus externus abdominis allows the establishment of a reliable animal model for studying intervertebral disc degeneration.

[The application of cervical arthroplasty with Mobi-C for treatment of cervical spondylotic radiculopathy].

OBJECTIVE: To investigate the clinical effectiveness of cervical arthroplasty with Mobi-C prosthesis for treatment of cervical spondylotic radiculopathy. METHODS: From March 2008 to November 2009, a group of 67 patients with cervical spondylotic radiculopathy were analyzed retrospectively. The short form-36 physical component summary (SF-36) and visual analogue scale (VAS) score were used to compare clinical outcome pre- and postoperatively. The follow-up was performed at 3 d, 3 months, 6 months and 1 year postoperatively. Static and dynamic radiography were taken to evaluate height of disc space, range of motion (ROM) and heterotopic ossification (HO) of index levels. RESULTS: Fifty-one cases were followed up, 16 cases were lost. Average follow-up was for 19.7 months (13 - 31 months). All of patients had improvement for clinical symptoms. There was a significant difference on SF-36 between pre- and postoperatively. The significant difference was found in VAS score in which neck pain was decreased from preoperative 4.6 ± 0.4 to postoperative 2.0 ± 0.5 (P < 0.05), arm pain was decreased from preoperative 6.5 ± 0.4 to postoperative 1.3 ± 0.4 (P < 0.05). There was a significant difference in height of disc space which was increased from preoperative (6.5 ± 1.1) mm to (7.7 ± 0.9) mm (P < 0.05). ROM was increased from preoperative 7.2° ± 3.1° to latest follow-up 8.1° ± 3.2°, however, no significant difference was found concerning ROM pre- and postoperatively (P > 0.05). No other complications were met during follow-up period other than the 17 cases of heterotopic ossification in ClassI, the 7 cases in Class II in 1 year postoperatively, but no any correlation were found between the radiographic finding in HO and clinical symptoms. CONCLUSIONS: Cervical arthroplasty with Mobi-C could improve neurofunctional symptoms, maintain ROM of index level and height of disc space. For accurate patient selection, long term follow-up is still needed in prospective randomized study.

[Neuroprotection of a neotype transactivating-brain-derived neurotrophic factor fusion protein with penetrating activity of blood-brain barrier].

OBJECTIVE: To identify the dural activities of neuroprotection and penetrating blood-brain barrier (BBB) for TAT-BDNF (transactivating-brain-derived neurotrophic factor) fusion protein to explore an alternative treatment for the injury of central nerve system (CNS). METHODS: With molecular cloning techniques, a recombinant vector termed pTAT-BDNF was constructed to encode both TAT protein transduction domain and human BDNF. Purified TAT-BDNF fusion protein was generated from Escherichia coli BL21 (DE3). The injury model was established with in vitro cultured cortical neurons of neonatal rats. To observe the neuroprotective effects of TAT-BDNF fusion protein on glutamate-mediated excitotoxic insults, the contents of lactate dehydrogenase (LDH) were measured by spectrophotometry. Immunofluorescence and Hoechst 33342 analyses were used to observe the morphological changes. Immunocytochemical and Nissl stain analysis of TAT-BDNF content in CNS tissue were performed after an intravenous injection of TAT-BDNF fusion protein in normal or spinal cord injured rats. RESULTS: During the study of glutamate-induced excitotoxic insults, as compared with the control group, TAT-BDNF could decrease the apoptotic ratio, reduce the leakage of LDH and enhance the survival of neurons (P < 0.05 ). As demonstrated by immunohistochemistry, TAT-BDNF fusion protein was efficiently delivered into rat brain and spinal cord tissues at 4 h post-injection. At Day 7 post-injury, Nissl stain show that the number and morphology of neurons in the TAT-BDNF group were better than those in the control group. CONCLUSION: The synthetic neotype TAT-BDNF possess the dual biological effects of neuroprotection and penetrating BBB.

Metformin stimulates osteoprotegerin and reduces RANKL expression in osteoblasts and ovariectomized rats.

Anti-diabetic drug metformin has been shown to enhance osteoblasts differentiation and inhibit osteoclast differentiation in vitro and prevent bone loss in ovariectomized (OVX) rats. But the mechanisms through which metformin regulates osteoclastogensis are not known. Osteoprotegerin (OPG) and receptor activator of nuclear factor κB ligand (RANKL) are cytokines predominantly secreted by osteoblasts and play critical roles in the differentiation and function of osteoclasts. In this study, we demonstrated that metformin dose-dependently stimulated OPG and reduced RANKL mRNA and protein expression in mouse calvarial osteoblasts and osteoblastic cell line MC3T3-E1. Inhibition of AMP-activated protein kinase (AMPK) and CaM kinase kinase (CaMKK), two targets of metformin, suppressed endogenous and metformin-induced OPG secretion in osteoblasts. Moreover, supernatant of osteoblasts treated with metformin reduced formation of tartrate resistant acid phosphatase (TRAP)-positive multi-nucleated cells in Raw264.7 cells. Most importantly, metformin significantly increased total body bone mineral density, prevented bone loss and decreased TRAP-positive cells in OVX rats proximal tibiae, accompanied with an increase of OPG and decrease of RANKL expression. These in vivo and in vitro studies suggest that metformin reduces RANKL and stimulates OPG expression in osteoblasts, further inhibits osteoclast differentiation and prevents bone loss in OVX rats.

[Lithium chloride combined with human umbilical cord blood mesenchymal stem cell transplantation for treatment of spinal cord injury in rats].

OBJECTIVE: To observe the effects of lithium chloride combined with human umbilical cord blood mesenchymal stem cell (hUCB-SCs) transplantation in the treatment of spinal cord injury in rats. METHODS: Eighty female SD rats with complete T9 spinal cord transaction were randomized into 4 groups (n=20), namely the control group (group A), lithium chloride group (group B), hUCB-SCs group (group C) and hUCB-SCs(+) lithium chloride group (group D). On days 1 and 3 and the last days of the following weeks postoperatively, the motor function of the hindlimb of the rats were evaluated according to the BBB scores. At 8 weeks, all the rats were sacrificed and the spinal cords were taken for morphological observation. The spinal cord tissues at the injury site were observed with Brdu nuclear labeling to identify the survival and migration of the transplanted SCs. The regeneration and distribution of the spinal nerve fibers were observed with fluorescent-gold (FG) spinal cord retrograde tracing. RESULTS: Brdu labeling showed that the transplanted hUCB-SCs survived and migrated in the spinal cord 8 weeks postoperatively in groups C and D. FG retrograde tracing identified a small amount of pyramidal cells that migrated across the injury site in groups C and D. The BBB scores of the hindlimb motor function 8 weeks postoperatively were 4.11∓0.14, 4.50∓0.15, 8.31∓0.11 and 11.15∓0.18 in groups A, B, C and D, respectively. CONCLUSION: Lithium chloride can promote the survival and differentiation of hUCB-SCs into neural cells at the injury site. Lithium chloride combined with hUCB-SCs transplantation may accelerate functional recovery of the hindlimbs in rats with complete transection of the spinal cord.

[Unilateral pedicle screw fixation plus interbody fusion by Quadrant system through spatium intermuscular of multifidus].

OBJECTIVE: To explore the clinical outcome of unilateral pedicle screw fixation plus single cage interbody fusion through spatium intermuscular of multifidus by Quadrant system. METHODS: From April 2008 to April 2009, 47 patients underwent unilateral pedicle screw fixation plus single cage interbody fusion through spatium intermuscular of multifidus. There were 22 males and 25 females with the mean age of 58.2 years (range, 46-74 years). Among them 12 cases had far-lateral lumbar disc herniation, 7 cases had post-discectomy recurrence, and 28 cases had degenerative instability. Thirty-seven cases were treated with lumbar interbody fusion through transforaminal approach, 10 cases through posterior approach. After surgery, the radiography was carried out to demonstrate the fusion status, and the Nakai criterion was used for assessment. RESULTS: The average skin incision length was 3.2 cm (range, 3.0 to 3.5 cm), the average operative time was 90 min (range, 70 to 160 min), and the average blood loss was 130 ml (range, 90 to 360 ml). All cases were followed up for 8 - 20 months (average 13.6 months). Postoperative radiography showed no evidence of instrument failure, and 43 cases got bone fusion, 4 cases got suspicious fusion. At final followed-up the average leg pain VAS decreased from 7.4 ± 1.1 preoperatively to 2.4 ± 1.3 postoperatively, the average low back pain VAS decreased from 6.7 ± 1.3 preoperatively to 1.8 ± 1.5 postoperatively. According to Nakai criterion, 31 cases were rated as excellent, 11 cases as good, and 5 cases as fair with the total excellent and good rate of 89.4%. CONCLUSIONS: Unilateral pedicle screw fixation plus single cage interbody fusion through spatium intermuscular of multifidus has some advantages of minimal invasiveness, less blood loss, less complications and reliable curative effect. It is a satisfactory lumbar fusion method under suitable indication.