[Effect of functionalized multi-walled carbon nanotubes on L02 cells].

OBJECTIVE: To investigate the cytotoxic effect of multi-walled carbon nanotubes (MWCNTs) on human liver L02 cells and its relevant mechanism. METHODS: MWCNTs, carboxyl modification MWCNTs (MWCNTs-COOH), and hydroxyl modification MWCNTs (MWCNTs-OH) were characterized by transmission electron microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. The carbon nanotubes at concentrations of 12.5, 25, 50, 100, and 200 µg/ml were incubated with human liver L02 cells for 24, 48 and 72 hours, respectively. The cell viability was evaluated by water soluble tetrazolium salts assay and the intercellular reactive oxygen species induced by the carbon nanotubes were detected by 2', 7'-dichlorodihydrofluorescein diacetate method. RESULTS: Transmission electron microscope showed that the average outside diameters (10 to 20 nm) and the average length (10 to 30 µm) of the three MWCNTs were similar. Scanning electron microscope indicated that the three MWCNTs had a similar surface topography. X-ray photoelectron spectroscopy demonstrated that the MWCNTs-COOH and MWCNTs-OH had relatively high peak areas at 289 and 286ev, respectively,indicating that they have been modified by carboxyl and hydroxyl groups,respectively. Water soluble tetrazolium salts assay showed that the MWCNTs-COOH was less cytotoxic when compared to MWCNTs which demonstrated to be slightly more cytotoxic than MWCNTs-OH. The capability to induce increase in intracellular reactive oxygen species was in the following order: MWCNTs > MWCNTs-COOH > MWCNTs-OH. CONCLUSIONS: Modification of MWCNTs with carboxyl group and hydroxyl group improves the biocompatibility of MWCNTs to some extents. MWCNTs-COOH has better compatibility than MWCNTs at the low concentration,and MWCNTs-OH showed better compatibility than MWCNTs after 48 hours. Different mechanisms may be involved in the interaction between cells and the MWCNTs with different chemical surfaces.

Establishing a noninvasive canine model of lumbar intervertebral disc degeneration through cumulative axial load and compound motion / 中华骨科杂志

Objective:To investigate the feasibility of establishing a canine model of lumbar intervertebral disc degeneration through the application of cumulative axial load and a six-phase combined motion on the vertical sitting dog's lumbar spine.Methods:Twenty adult female grass dogs, each weighing 10.0±0.5 kg, were randomly divided into two groups, with 10 dogs in each group. In the model group, dogs were secured to an exercise machine in a vertical position, and six phases of lumbar spine movement (flexion and extension, left and right lateral flexion, left and right rotation, 45° each) were combined with a specific number of cycles under continuous axial load (245 N). In the control group, dogs were secured to the exercise machine in a vertical position without any intervention. Radiographic examinations were performed before and after 20,000, 50,000, 100,000, and 150,000 compound exercises in the model group. The disc height index (DHI) was measured through lateral X-ray, and MRI T2-mapping was used for quantitative analysis of intervertebral disc degeneration. When intervertebral disc degeneration was evident on MRI T2-weighted imaging (modified Pfirrmann system > Grade V), the combined motion was halted. Micro-CT quantitative analysis of bone mineral density (BMD) in the upper and lower endplates, trabecular bone structure, and histological staining (HE staining, "O" staining, Sirius red staining) were employed to verify and assess the degree of intervertebral disc degeneration.Results:After 50,000 compound exercises, mild degeneration of the intervertebral discs at L 6-7 and L 7S 1 was observed on T2-weighted imaging. With the accumulation of exercise load, the degree of degeneration progressively increased, reaching a moderate degree of degeneration after 100,000 composite exercises, and DHI began to decrease. Mild degeneration was also observed in the upper L 5-6 intervertebral disc. When the cumulative exercise volume reached 150,000 repetitions, the height of intervertebral spaces in the L 5-6, L 6-7, and L 7S 1 segments further decreased, and the intervertebral discs exhibited severe degeneration (improved Pfirrmann grading system Grades IV-VI). The upper L 4-5 intervertebral discs also displayed mild degeneration. Histological scores were as follows: L 5-6 (8.2±0.8), L 6-7 (9.5±0.7), and L 7S 1 (10.3±0.5), indicating a degree of degeneration in the order of L 5-6<L 6-7<L 7S 1. HE and safranine "O" staining confirmed the significant collapse of the intervertebral spaces in the L 5-6, L 6-7, and L 7S 1 segments, characterized by severe shrinkage of the nucleus pulposus tissue, a disordered internal structure, and nearly absent vacuolar-like nucleus pulposus cells. Sirius red staining revealed pronounced folds, disordered arrangement, and multiple fractures in the fibers of the anterior and posterior rings of the intervertebral disc. The posterior ring of the disc exhibited more pronounced changes than the anterior ring, and the thickness of the bone endplate and bone trabecular density became thinner and less dense. Micro-CT quantitative analysis further confirmed that the BMD and number of trabeculae in the upper and lower endplates of the L 5-6, L 6-7, and L 7S 1 segments were significantly lower than those in the control group and other segments of the model group, while the trabecular separation was significantly higher than that in the control group and other segments of the model group. Conclusion:The utilization of the "Lumbar Composite Exercise Machine" can effectively replicate the biomechanical and kinematic characteristics of human lumbar intervertebral discs. Cumulative axial load and six-phase composite exercise can induce varying degrees of chronic degeneration in canine lumbar intervertebral discs, which is related to the exercise load, particularly in the L 5-6, L 6-7, and L 7S 1 segments.

[Cellular uptake and cytotoxicity of modified chitosans as gene carriers].

OBJECTIVE: To evaluate the effects of arginine modified chitosan or hexadecylated modified chitosan as gene carriers on the cellular uptake by vascular smooth muscle cells and its in vitro cytotoxicity. METHODS Plasmid DNA was labeled with alpha-32P-dATP and complexed with the modified chitosans or unmodified chitosan to form nanoparticle complexes by complex coacervation method. Uptake of all kinds of chitosan/ DNA nanoparticle complexes (CNC) by A10 cells was measured by beta-liquid scintillation counting. The in vitro cytotoxicity of the CNC was evaluated by the 3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay. RESULTS: The diameters of the CNC ranged from 55.9-174.9 nm and the zeta potentials were from 10. 8 mV for the arginine modified chitosan/DNA nanoparticle complexes (ACNC) to 1.8 mV for the hexadecylated chitosan/DNA nanoparticle complexes (HCNC). The cellular uptake of the modified chitosan/ DNA nanoparticle complexes (MCNC) by A10 cells increased significantly when compared with the unmodified chitosan/DNA nanoparticle complexes (UCNC) (P < 0.05), with the HCNC at N/P ratio of 1:1 and the ACNC at ratio of 8:1 showing the highest cellular uptake (1.3 fold higher than UCNC, P < 0.05). MCNC were much less cytotoxic when compared with Lipofectamine 2000-DNA nanoparticles. CONCLUSION: DNA nanoparticle complexes prepared with either arginine or hexadecylated modified chitosan can improve the cellular uptake of the DNA, while the in vitro cytotoxicity of both of the modified chitosan is much less than that of Lipofectamine 2000.

Feasibility and clinical effect of gelatin sponge in reducing bone cement leakage in percutaneous kyphoplasty / 中华创伤杂志

Objective:To explore the feasibility and clinical efficacy of gelatin sponge packing in reducing bone cement leakage in percutaneous kyphoplasty (PKP).Methods:A retrospective case-control study was conducted in data of 171 patients (171 vertebrae) with monosegmental lumbar osteoporosis compressive fracture treated by PKP from January 2015 to December 2018 in Sichuan Orthopedic Hospital. There were 66 males and 105 females, with the age of (67.9±6.7)years (range, 60-87 years). There were 22 patients with T 10 fracture, 28 with T 11 fracture, 37 with T 12 fracture, 34 with L 1 fracture, 32 with L 2 fracture and 18 with L 3 fracture. A total of 80 patients were pre-filled with gelatin sponge before injection (Group A), and 91 patients were not filled with gelatin sponge before injection (Group B). The operation time, amount of bone cement, and rate of bone cement leakage were recorded. The change of anterior vertebral height, Cobb angle, visual simulation score (VAS) and Oswestry disability index (ODI) were compared before operation and at postoperative 1 day, 3 months, 6 months, 12 months. Results:All patients were followed up for 1-12 months [(12.8±0.6)months]. The operation time in Group A and B was (48.3±1.2)minutes and (42.3±1.3)minutes ( P<0.05). The amount of bone cement in Group A and B was (5.4±0.8)ml and (5.6±0.7)ml ( P>0.05). The incidence of bone cement leakage in Group A and B was 11% (9/80) and 26% (24/91) ( P<0.05). There was no significant difference between the two groups in the anterior height of injured vertebrae, change of Cobb angle, VAS and ODI before and after operation ( P>0.05). Conclusion:Gelatin sponge can reduce the rate of bone cement leakage in PKP for the treatment of thoracolumbar osteoporosis compressive fracture, and has similar effect with PKP in correcting kyphosis, alleviating pain and improving life quality.

Application of enhanced recovery after surgery in postoperative rehabilitation of osteoporotic lumbar compression fractures with percutaneous vertebroplasty or percutaneous kyphoplasty / 中国骨伤

OBJECTIVE@#To study effects of postoperative regular training of core muscle strength guided by the concept of enhanced recovery after surgery (ERAS) on the rehabilitation of elderly patients with osteoporotic lumbar vertebral compression fracture after vertebroplasty (PVP) and kyphoplasty(PKP).@*METHODS@#Ninety-four elderly patients with osteoporotic lumbar compression fractures who underwent PKP or PVP from January 2016 to January 2018 and met inclusion criteria were divided into observation group and control group. All the patients were treated with routine anti osteoporosis therapy after operation. There were 47 patients in the observationgroup, including 18 males and 29 females, with an average age of (62.62±3.21) years old;in the control group, there were 47 cases, including 17 males and 30 females, with an average age of (62.38±2.84) years old. The patients in the control group were trained by traditional way, and the patients in observation group were instructed to conduct regular training of core muscle strength according to ERAS concept. The patients were followed up for 1, 3 and 6 months after operation. Patients' conditions were quantitatively evaluated according to Barthel scale, JOA low back pain score and Oswestry Disability Index, and the differences in treatment effects between two groups were statistically analyzed and compared.@*RESULTS@#All the patients were followed up, and the Barthel scale, JOA low back pain score and Oswestry Disability Index score of the observation group were all better than those of the control group on the 1st and the 3rd months after surgery(@*CONCLUSION@#Early regular core strength training has a positive effect on early functional recovery and improvement of life ability after PKP or PVP for elderly patients with osteoporotic lumbar compression fractures, which is in line with the concept of accelerated rehabilitation surgery.

Preliminary application of CPC/PMMA composite bone cement in kyphoplasty for the elderly / 中国骨伤

OBJECTIVE@#From the perspective of clinical application to analyze the effectiveness and reliability of CPC/PMMA bone cement in percutaneous kyphoplasty (PKP) for the treatment of elderly patients with osteoporotic thoracolumbar fractures.@*METHODS@#A retrospective analysis was performed on 62 patients with osteoporotic compression fracture of single-vertebral thoracic or lumbar segment who underwent PKP surgery and had a bone density less than or equal to -3.0 SD from February 2016 to December 2016. Among them, 23 patients were in CPC/PMMA group, with an average age of (77.6±2.2) years old, 39 patients in PMMA group, with an average age of (77.1±1.1) years old. The indexes between two groups were compared, including the visual analogue scale (VAS), height ratio of anterior vertebra (AVHR), local Cobb angle, cement leakage, new adjacent vertebral fracture(NAVF).@*RESULTS@#There were no significant difference in gender, age, follow-up time and preoperative VAS, AVHR, local Cobb angle between two groups (>0.05), at the 1 day after operation, VAS, AVHR, local Cobb angle in all patients got obvious improvement (0.05). At the same time, there was no statistically significant difference in the incidence of new adjacent vertebral fracture and cement leakage (>0.05). The pain in both groups continued to improve at follow up after operation (<0.05), the local Cobb angle increased (<0.05) and AVHR decreased slightly (<0.05). However, the images of conventional methods (X-ray or CT) could not find signs about CPC degeneration and new bone ingrowth.@*CONCLUSION@#CPC/PMMA composite bone cement is safe and reliablein PKP for treatment of elderly patients with osteoporotic thoracolumbar fractures, which can effectively relieve pain and maintain vertebral body stability. It has the same curative effect as PMMA bone cement. It was worthy to research more in future, although no direct evidences support the CPC/PMMA composite bone cement can reduce the incidence of adjacent vertebral fracture, CPC degeneration or new bone ingrowth.

Clinical comparative study of short-segment and long-segment fixation for single-segment thoracic and lumbar spine III stage Kümmell disease / 中国骨伤

OBJECTIVE@#By comparing the clinical efficacy of short-segment and long-segment fixation for single-segment thoracic and lumbar spine III stage Kümmell disease to explore a more suitable fixed segment for the disease.@*METHODS@#The clinical data of 46 patients with single-segment thoracic and lumbar spine III stage Kümmell disease treated from July 2013 to December 2016 were retrospectively analyzed. Forty-six patients were divided into short-segment fixation group(one vertebra above and below the diseased vertebra) and long-segment fixation group(two vertebrae on the upper and lower of the diseased vertebra) according to different methods of cement stick fixation. There were 25 patients in the short-segment fixation group, including 9 males and 16 females, with an average age of (75.3±4.5) years old, lumbar spine bone mineral density T-value of (-3.1±0.3) g/cm³, follow-up time of (13.0±2.3) months; there were 21 patients in long-segment fixation group, 6 males and 15 females, with an average age of (74.5±3.9) years old, lumbar spine bone mineral density T-value of (-3.2±0.3) g/cm³, follow-up time of (14.7±3.6) months.The gender, age, follow-up time, operation time, intraoperative blood loss, cement leakage, and the rate of adjacent vertebrae fractures were compared between two groups, as well as pain VAS score, ODI, and kyphosis angle before and after surgery.@*RESULTS@#There were no significant differences in age, gender, bone density, pain VAS score, ODI, and kyphosis between two groups before surgery. The operation time and intraoperative blood loss of short-segment fixation group were less than that of long-segment fixation group. The pain VAS score, ODI and kyphosis of the two groups were significantly improved at 7 days after the operation and at the latest follow-up, there was no significant difference between two groups. There were no significant differences in bone cement leakage(9/25 vs 11/21) and adjacent vertebrae fractures(4/25 vs 3/21).@*CONCLUSIONS@#Both long-segment fixation and short-segment fixation can effectively relieve pain, correct kyphosis, improve functional index, and achieve better clinical results, but short-segment fixation has less operation time and less intraoperative blood. So single-segment thoracic and lumbar spine III stage Kümmell disease does not need to extend the fixed segment, short-segment fixation is more in line with clinical needs and worthy of further study.

Impact of the tissue factor pathway inhibitor gene on apoptosis in human vascular smooth muscle cells.

Tissue factor pathway inhibitor (TFPI) plays a vitally important role in the blood coagulation pathway. Recent studies indicated that TFPI induces apoptosis in vascular smooth-muscle cells (VSMCs) in animals. The present study investigated whether the TFPI gene could also induce apoptosis in human vascular smooth-muscle cells (hVSMCs). Such cells were isolated from human umbilical arteries and subsequently transfected with pIRES-TFPI plasmid (2 µg/mL). MTT assaying and cell counting were applied to measure cell viability and proliferation, RT-PCR was utilized to analyze TFPI gene expression in the cells. Apoptosis was analyzed by fluorescence activated cell sorting (FACS). Several key proteins involved in apoptosis were examined through Western blotting. It was shown that TFPI gene transfer led to its increased cellular expression, with a subsequent reduction in hVSMC proliferation. Further investigation demonstrated that TFPI gene expression resulted in lesser amounts of procaspase-3, procaspase-8 and procascase-9, and an increased release of mitochondrial cytochrome c (cyt-c) into cytoplasm, thereby implying the involvement of both extrinsic and intrinsic pathways in TFPI gene-induced apoptosis in hVSMCs.

Impact of the tissue factor pathway inhibitor gene on apoptosis in human vascular smooth muscle cells

Tissue factor pathway inhibitor (TFPI) plays a vitally important role in the blood coagulation pathway. Recent studies indicated that TFPI induces apoptosis in vascular smooth-muscle cells (VSMCs) in animals. The present study investigated whether the TFPI gene could also induce apoptosis in human vascular smooth-muscle cells (hVSMCs). Such cells were isolated from human umbilical arteries and subsequently transfected with pIRES-TFPI plasmid (2 μg/mL). MTT assaying and cell counting were applied to measure cell viability and proliferation, RT-PCR was utilized to analyze TFPI gene expression in the cells. Apoptosis was analyzed by fluorescence activated cell sorting (FACS). Several key proteins involved in apoptosis were examined through Western blotting. It was shown that TFPI gene transfer led to its increased cellular expression, with a subsequent reduction in hVSMC proliferation. Further investigation demonstrated that TFPI gene expression resulted in lesser amounts of procaspase-3, procaspase-8 and procascase-9, and an increased release of mitochondrial cytochrome c (cyt-c) into cytoplasm, thereby implying the involvement of both extrinsic and intrinsic pathways in TFPI gene-induced apoptosis in hVSMCs.

Effect of functionalized multi-walled carbon nanotubes on L02 cells / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the cytotoxic effect of multi-walled carbon nanotubes (MWCNTs) on human liver L02 cells and its relevant mechanism.</p><p><b>METHODS</b>MWCNTs, carboxyl modification MWCNTs (MWCNTs-COOH), and hydroxyl modification MWCNTs (MWCNTs-OH) were characterized by transmission electron microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. The carbon nanotubes at concentrations of 12.5, 25, 50, 100, and 200 μg/ml were incubated with human liver L02 cells for 24, 48 and 72 hours, respectively. The cell viability was evaluated by water soluble tetrazolium salts assay and the intercellular reactive oxygen species induced by the carbon nanotubes were detected by 2', 7'-dichlorodihydrofluorescein diacetate method.</p><p><b>RESULTS</b>Transmission electron microscope showed that the average outside diameters (10 to 20 nm) and the average length (10 to 30 μm) of the three MWCNTs were similar. Scanning electron microscope indicated that the three MWCNTs had a similar surface topography. X-ray photoelectron spectroscopy demonstrated that the MWCNTs-COOH and MWCNTs-OH had relatively high peak areas at 289 and 286ev, respectively,indicating that they have been modified by carboxyl and hydroxyl groups,respectively. Water soluble tetrazolium salts assay showed that the MWCNTs-COOH was less cytotoxic when compared to MWCNTs which demonstrated to be slightly more cytotoxic than MWCNTs-OH. The capability to induce increase in intracellular reactive oxygen species was in the following order: MWCNTs > MWCNTs-COOH > MWCNTs-OH.</p><p><b>CONCLUSIONS</b>Modification of MWCNTs with carboxyl group and hydroxyl group improves the biocompatibility of MWCNTs to some extents. MWCNTs-COOH has better compatibility than MWCNTs at the low concentration,and MWCNTs-OH showed better compatibility than MWCNTs after 48 hours. Different mechanisms may be involved in the interaction between cells and the MWCNTs with different chemical surfaces.</p>

Cellular uptake and cytotoxicity of modified chitosans as gene carriers / 中国医学科学院学报

<p><b>OBJECTIVE</b>To evaluate the effects of arginine modified chitosan or hexadecylated modified chitosan as gene carriers on the cellular uptake by vascular smooth muscle cells and its in vitro cytotoxicity. METHODS Plasmid DNA was labeled with alpha-32P-dATP and complexed with the modified chitosans or unmodified chitosan to form nanoparticle complexes by complex coacervation method. Uptake of all kinds of chitosan/ DNA nanoparticle complexes (CNC) by A10 cells was measured by beta-liquid scintillation counting. The in vitro cytotoxicity of the CNC was evaluated by the 3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay.</p><p><b>RESULTS</b>The diameters of the CNC ranged from 55.9-174.9 nm and the zeta potentials were from 10. 8 mV for the arginine modified chitosan/DNA nanoparticle complexes (ACNC) to 1.8 mV for the hexadecylated chitosan/DNA nanoparticle complexes (HCNC). The cellular uptake of the modified chitosan/ DNA nanoparticle complexes (MCNC) by A10 cells increased significantly when compared with the unmodified chitosan/DNA nanoparticle complexes (UCNC) (P < 0.05), with the HCNC at N/P ratio of 1:1 and the ACNC at ratio of 8:1 showing the highest cellular uptake (1.3 fold higher than UCNC, P < 0.05). MCNC were much less cytotoxic when compared with Lipofectamine 2000-DNA nanoparticles.</p><p><b>CONCLUSION</b>DNA nanoparticle complexes prepared with either arginine or hexadecylated modified chitosan can improve the cellular uptake of the DNA, while the in vitro cytotoxicity of both of the modified chitosan is much less than that of Lipofectamine 2000.</p>