Genetic diversity and population structure of Camellia huana (Theaceae), a limestone species with narrow geographic range, based on chloroplast DNA sequence and microsatellite markers.

Camellia huana is an endangered species with a narrow distribution in limestone hills of northern Guangxi and southern Guizhou provinces, China. We used one chloroplast DNA (cpDNA) fragment and 12 pairs of microsatellite (simple sequence repeat; SSR) markers to assess the genetic diversity and structure of 12 C. huana populations. A total of 99 alleles were detected for 12 polymorphic loci, and eight haplotypes and nine polymorphic sites were detected within 5200 bp of cpDNA. C. huana populations showed a low level of genetic diversity (n = 8, Hd = 0.759, Pi = 0.00042 for cpDNA, N A  = 3.931, H E  = 0.466 for SSRs), but high genetic differentiation between populations (F ST  = 0.2159 for SSRs, F ST  = 0.9318 for cpDNA). This can be attributed to the narrow distribution and limestone habitat of C. huana. STRUCTURE analysis divided natural C. huana populations into two groups, consistent with their geographical distribution. Thus, we suggest that five natural C. huana populations should be split into two units to be managed effectively.

[Treatment of severely osteoporotic vertebral compression fractures with the vertebral body stent system and percutanous kyphoplasty combined with zoledronic acid].

OBJECTIVE: To investigate the clinical efficacy of vertebral body stent (VBS) system and percutanous kyphoplasty (PKP) combined with zoledronic acid for the treatment of severely osteoporotic compression vertebral fractures (OVCFs). METHODS: The clinical data of 48 patients with osteoporotic thoracolumbar fractures treated from December 2017 to December 2018 were retrospectively analyzed, including 13 males and 35 females, aged 55 to 92 years old with an average (71.2±10.5) years. All patients were treated with VBS system PKP surgery, and zoledronic acid injection was used for anti-osteoporosis treatment after operation. The VAS scores ODI, the height of diseasedvertebral lost were compared before operation, 3 d and half a year after operation, and whether there was re-fracture of diseased or adjacent vertevrae after operation was observed. RESULTS: Before operation, 3 d and half a year after operation, VAS scores were 7.60±0.12, 3.00±0.46, 1.20±0.23, ODI were(82.00±0.32)%, (30.00±1.50) %, (18.00±0.16) %, the height of diseased vertebral lost were (12.00±0.43) mm, (3.00± 0.15) mm, (3.60±0.51) mm respectively. Postoperative VAS score, ODI, the height of diseased vertebral lost were obviously improved (P<0.05), and there was no significant difference between 3 d and half a year after operation (P>0.05). All the 48 patients were followed up with an average time of (6.6±0.5) months. All the incisions healed at grade A after operation, and no re-fracture of diseased vertebrae or adjacent vertebrae was found at the final follow-up. CONCLUSION: VBS system and PKP combined with zoledronic acid in the treatment of OVCFs not only may effectively relieve the pain in the thoracolumbar back, improve the mobility of the thoracolumbar, but also can restore the height of the vertebral body to the maximum extent, and prevent the re-fracture of the affected vertebrae and adjacent vertebrae, which is worthy to spread in clinic.

[Study on early screening of high saponin ginseng lines].

The study aims at screening the specific bands by PCR, quickly and accurately evaluating the quality of ginseng seeding, accelerating the process of ginseng breeding. Based on the correlation of genetic differences and saponin content between individuals, a pair of specific primer GC1 was screened by PCR. According to the experiment by L16 (45) orthogonal test, a PCR system most suitable for GC1 was established, which came out total 25 µL reaction system containing DNA 2.60 mg•L⁻¹, Mg²âº 1.44 mmol•L⁻¹, dNTP 0.19 mmol•L⁻¹, primer 0.32 µmol•L⁻¹ and Taq enzyme concentration 0.076 U•µL⁻¹. By comparing the saponin content and the GC1 PCR electrophoretogram of samples, the ginseng, with 1 200 bp specific band by PCR of GC1, the contents of 9 monosodium saponins and their additions were higher than others, which provided a reliable method for accelerating the process of ginseng breeding. The sequence was sequenced and 99% homologous to glycerol-3-phosphate dehydrogenase.

Resveratrol inhibits interleukin 1ß-mediated inducible nitric oxide synthase expression in articular chondrocytes by activating SIRT1 and thereby suppressing nuclear factor-κB activity.

In chondrocytes, resveratrol, a natural SIRT1 activator, exerts an anti-inflammatory response via inhibition of nuclear factor kappaB (NF-κB). Given that SIRT1 inhibits the transactivation potential of NF-κB by deacetylating acetylated lysines in p65, the NF-κB subunit, we investigated the effects of resveratrol-activated SIRT1 on articular chondrocytes. We found that when chondrocytes were stimulated with interleukin 1ß (IL-1ß), the time- and dose-dependent expression of inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) production was suppressed by resveratrol. Resveratrol-activated SIRT1 mediated this suppression. SIRT1 suppressed not only the nuclear translocation of NF-κB but also the acetylation of p65. Furthermore, acetylated Lys310 in p65, which must be present for transactivation activity, was the immediate downstream target of SIRT1. Therefore, SIRT1 protects against the inflammatory response induced by IL-1ß in articular chondrocytes. Resveratrol, as an activator of SIRT1, merits consideration as a therapeutic agent in the treatment and prevention of osteoarthritis.

Correlation between MR imaging and discography with provocative concordant pain in patients with low back pain.

OBJECTIVE: this study aimed to correlate magnetic resonance (MR) findings and discography with pain response at provocative discography in patients with low back pain. METHODS: ninety-three patients who underwent MR imaging of the lumbar spine and subsequent provocation discography as part of a clinical evaluation of low back pain were enrolled in the study. MR images were then evaluated for disc degeneration, high-intensity zone (HIZ), and endplate abnormalities. In the procedure of discography, concordant pain was denoted as positive, whereas discordant pain and no pain were denoted as negative. Finally, MR and discographic findings were analyzed by w2 test based on results of concordant pain. RESULTS: discography was conducted on 256 discs successfully, 116 discs of which presented with concordant pain, and the others presented with discordant pain. There were 141 discs we reevaluated as Grade I-III on MR images, 17 of which presented with concordant pain; 115 were evaluated as Grade IV-V, 99 of which presented with concordant pain. HIZ was found in 60 discs,52 of which had concordant pain. The endplate abnormalities we reobserved in 58 discs, 51 of which manifested concordant pain. Concordant pain was significant correlated with Type IV-V discs on discography (w2=144.08, r=0.60, P<0.01), Grade IV-V disc degeneration on MR image (w2=137.11, r=0.59, P<0.01), the presence of HIZ (w2=51.93, r=0.41, P<0.01), and endplate abnormalities (w2=52.76, r=0.41, P<0.01). DISCUSSION: disc degeneration grades on MR imaging showedan association with discographic grades. Type IV-V discs on discography, Grade IV-V disc on MR images, the presence of HIZ,and endplate abnormalities might indicate discogenic pain inpatients with chronic low back pain.

[Treatment of flatfoot deformity with concurrent spinal disease in children].

OBJECTIVE: To study the curative effect of operation to flatfoot deformity with concurrent spinal disease in children. METHODS: A retrospective survey was performed in 8 flatfoot patients with concurrent spinal disease from January 2004 to January 2008. Every case received special operative treatment. After casting, achilles tendon prolongation, reefing or tendon transfer, rehabilitation therapy was performed sequentially. Radiographs and clinical outcomes were evaluated during the follow-up. RESULTS: Six patients were followed up. There were 2 feet in 1 female and 7 feet in 5 males. The complications included tethered cord syndrome (n = 1), T12-S1 vertebral canal arachnoid cyst (n = 1), cerebral palsy and scoliosis (n = 1) and scoliosis and spinal bifida occult (n = 3). The average age was 8.4 (4 - 14) years old and the average follow-up time 22 (14 - 64) months. All cases were satisfied with the appearance and function according to Maryland foot score. Five were excellent, 2 good and 2 fair postoperatively versus 2 fair and 7 failed preoperatively. The total excellent and good rate was 77.8%. In the early stage after tendon transfer in 4 patients, the lateral view of height arch, talus-first metatarsal angle, calcaneus-navicular-first metatarsal angle and talonavicular coverage angle improved. Yet it lost the improved angle and reverted to the pre-operative state. No degenerative change was detected in tarsus joints during the long follow-up. CONCLUSION: The special and sequential surgical procedure may be an effective regimen in the treatment of flatfoot deformity with concurrent spinal disease in children.

Double role of Fas ligand in the apoptosis of intervertebral disc cells in vitro.

Fas ligand (FasL) may play an important role in maintaining the immune privilege of intervertebral disc (IVD). Besides, it is closely related to the apoptosis of degenerative disc cells. Nowadays, lots of reports have described about the paradoxical effects of FasL, although the effect of FasL on IVD cells is still under debate. In this study, we tried to investigate the effects of FasL on Fas expression and on the apoptosis of nucleus pulposus (NP) cells in Sprague-Dawley rats. The results showed that the expression of Fas in NP cells was significantly increased by the recombinant FasL. Meanwhile, the apoptosis of NP cells increased markedly in a FasL dose-dependent manner. Interestingly, RNA interference results indicated that the increase of Fas expression and the NP cell apoptosis described previously were inhibited by Fas siRNA, suggesting that RNA interference might be one of novel strategies to prevent IVD cells from apoptosis.

[A 10-year-review (1998 - 2007) on 3449 cases of osteoporotic hip fractures: trend of hospitalization and inpatient costs].

OBJECTIVE: The purpose of this retrospective research was to analyze the trend of hospitalized prevalence in the past 10 years (1998 - 2007) and to estimate resource utilization associated with osteoporotic hip fractures, including hospital length of stay and inpatient costs in Guangzhou, China. METHODS: 3449 patients aged 50 years and older, hospitalized for primary diagnose of hip fractures in both hospitals in the past ten years were included in our study. Completed data was obtained retrospectively from the hospital medical records. Clinical parameters such as sex-specifics, hospital length of stay, inpatient costs, and the constitutions of the inpatient costs were analyzed with multiple statistics methods and regressions. RESULTS: Over the 10-year study period, the number of hospitalizations for hip fractures increased with a curve model. Male and female ratio was 1:1.95 with an average age of the patients as 76.32 +/- 9.52 years old. Average hospital length of stay was 23.59 +/- 13.48 days with no significant difference between males and females, years of admission and the different diagnoses. The number of hospitalization went to the top at the age of 70 to 79 years old (38.45%), followed by 80-89 years old (33.08%). Femoral neck fractures was significantly more than that of inter-trochanteric fractures in those patients aged 50 to 79 years (P < 0.01) but less than those intertrochanteric fractures aged 90 years and older (P < 0.05). Average inpatient costs is about 23.52 +/- 17.00 thousand Yuan (RMB) (femoral neck fractures is about 25.09 +/- 17.62 thousand Yuan and intertrochanteric fracture is 21.44 +/- 15.92 thousand Yuan) of which treatment costs (included implants, materials used in the theatre and routinely care of the wound) contributed 52%, pharmacy intervention 25%, operation 6%, ward expenditure 5%, radiology and physical investigation 5%, and chemistry test 4%. The inpatient cost went to a peak at the age of 60 - 69 years old and were significantly correlated with the hospital length of stay. The cost increased every year in the past 10 years by 6.18%. CONCLUSION: These results emphasized that the growing economic impact arising from the inpatient treatment of osteoporotic hip fractures and most of which related to treatment cost (include implants, materials used in the theatre and routinely care of the wound), and drugs and always correlated to length of hospital stay. Cost control should be paid more attention to the implants and drugs.

[Association of 86 bp variable number tandem repeat polymorphism of interleukin-1 receptor antagonist gene with lumbar disc disease].

OBJECTIVE: To investigate the association of 86 bp variable number tandem repeat (VNTR) polymorphism of interleukin-1 receptor antagonist (IL-1Ra) gene with lumbar disc disease and intervertebral disc degeneration. METHODS: The 86 bp VNTR polymorphism of IL-1Ra gene was analyzed with PCR and electrophoresis for 81 patients with lumbar disc disease and 101 volunteers without sciatica (control). The grade of intervertebral disc degeneration was determined with magnetic resonance imaging, and the association of 86 bp VNTR polymorphisms with lumbar disc disease and intervertebral disc degeneration in those younger than 45 years was assessed. RESULTS: The presence of 86bp VNTR polymorphisms of IL-1Ra gene was detected in both patients with lumbar disc disease and the control subjects. The distribution of 86 bp VNTR polymorphisms of IL-1Ra gene showed no significant difference between the two groups, but the distributions of 1/1, 1/2 and 2/2 or 1, 2 genotypes differed significantly. The current data did not support a significant association between the distribution of IL-1Ra gene 86bp VNTR polymorphism and lumbar disc degeneration. CONCLUSIONS: IL-1Ra gene 86bp VNTR polymorphism is present among Chinese population in association with lumbar disc disease, but not with lumbar disc degeneration.

IL-1beta sensitizes rat intervertebral disc cells to Fas ligand mediated apoptosis in vitro.

AIM: To determine the apoptotic effect of recombinant rat Fas Ligand on rat intervertebral disc cells pre-treated with IL-1beta in vitro, and the expression of Fas in cultured rat intervertebral disc cells. METHODS: Cells were isolated from the inner annulus fibrosus and transition zones of lumbar discs from Sprague-Dawley rats. The cells were grown in monolayer and divided in 5 treatment groups. IL-1beta (10 ng/mL), FasL (5, 20 ng/mL) with/without IL-1beta (10 ng/mL) pre-treatment was respectively added in Dulbeccoos modified Eagleos medium and Hamos F-12 medium with 1% fetal bovine serum. After 32 h, the cells were stained with annexin V-FITC and propidium iodide to evaluate apoptosis using flow cytometry and to analysis transcription of Fas using RT-PCR. RESULTS: Compared with control group, FasL (20 ng/mL), IL-1beta (10 ng/mL)+FasL (5 ng/mL), and IL-1beta (10 ng/mL)+FasL (20 ng/mL) induced significant apoptosis of the disc cells (P<0.01). Apoptosis was also induced by FasL 5 ng/mL (P<0.05); whereas, apoptosis was not induced by IL-1beta (10 ng/mL) (P>0.05). IL-1beta (10 ng/mL) enhanced the apoptosis-inducing effects of FasL (5 ng/mL) and FasL (20 ng/mL) in disc cells. Fas gene transcription in all groups and Fas expression in the 5 treatment groups were approximately 1.2-2.1-fold greater than control group (respectively, P<0.05). Additionally, Fas expression in FasL with IL-1beta pre-treatment groups were significantly up-regulated than in FasL groups (P<0.01). CONCLUSION: The results of this study showed disc cells pre-treated with IL-1beta increased apoptotic rate in response to FasL in vitro and provided insights to understand Fas/FasL system-mediated apoptosis in disc cells which would be enhanced due to inflammation factor in degenerative disc.

[Effect of interleukin-6 on the chondrocytes in the cartilage endplate of rabbits in vitro].

OBJECTIVE: To evaluate the effect of interleukin-6 (IL-6) on the biological behaviors of the chondrocytes in the cartilage endplate of rabbits. METHODS: Chondrocytes isolated from the cartilage endplate of New Zealand rabbits, verified for their biological characteristics by such means as toluidine blue staining for type II collagen, were treated with IL-6 at different concentrations. The proliferation of the chondrocytes was evaluated by MTT assay at different time points following the treatment, the cell cycle changes were determined by flow cytometry and the changes of aggrecan and type II collagen mRNAs detected by RT-PCR. RESULTS: At the concentrations of 10, 50 and 100 ng/ml, IL-6 did not obviously affect the rate of chondrocyte proliferation. IL-6 at 50 ng/ml resulted in no obvious changes of the cell cycle of the chondrocytes, but significantly decreased the expression of collagen IIa mRNA. CONCLUSION: IL-6 has no effect on the proliferation and cell cycle of the chondrocytes, but at higher concentrations, it inhibits matrix synthesis of the chondrocytes to promote intervertebral disc degeneration.

[Association of single nucleotide polymorphisms of IL-1b with lumbar disc disease].

This study was to explore the relationships between (-511)T>C and (+3954)C>T single nucleotide polymorphisms(SNP) in IL-1beta gene with lumbar intervertebral disc disease. We analyzed (-511)T>C and (+3954)C>T SNP in IL-1beta gene by the polymerase chain reaction-restriction fragment length polymorphism and electrophoresis methods respectively in 81 cases with lumbar disc disease and 101 healthy controls. The relationship between (-511)T>C and (+3954)C>T SNP in IL-1beta gene and lumbar disc disease in two groups was measured, so does the relationship between (-511)T>C and (+3954)C>T SNP in IL-1beta gene and intervertebral disc degeneration in those younger than 45-year-old. The results showed there were (-511)T>C and (+3954)C>T SNP in IL-1beta gene. There was a significant difference in the distribution of TT, TC and CC genotype or T, C genotype of (-511)T>C of IL-1beta in two groups. And there was no significant difference in the distribution of (+3954)C>T SNP in IL-1beta gene in two groups. There was no significant difference between the distribution of (-511)T>C and (+3954)C>T SNP in IL-1beta gene and intervertebral disc degeneration in those younger than 45-year-old. It suggested (-511)T>C SNP in IL-1beta gene be one of the susceptible alleles for Lumbar disc disease.

[Stability of lumbar spine after artificial disc replacement].

OBJECTIVE: To determine the influence of artificial disc replacement on the stability of lumbar. METHODS: Ten fresh human cadaveric lumbar spine specimens (9 males, 1 female) were tested. The donors had a mean age of 29.3 years old. The segments were fixed on a special testing device mounted in a universal testing machine. Physiological load with a maximum of 10 Nm was applied in the flexion, extension, right and left side bending. Moments were applied in 6 load steps: 0, 2, 4, 6, 8, and 10 Nm. Linearity migration and angle migration were recorded,and the mean flexibility coefficients were calculated. Four procedures of measurement were performed in every specimen: intact segments, segments after discectomy, segments after the artificial disc replacement, and segments after the artificial disc replacement with cutting posterior longitudinal ligament locally. RESULTS: The indexes we calculated of the segments after the discectomy were statistically different compared with the intact segments (P<0.05, P<0.01). The linearity migration,angle migration and mean flexibility coefficient in flexion/extension direction of the segments after the artificial disc replacement were statistically different compared with the segments after the discectomy (P<0.05, P<0.01), and there was a statistically significant increase in angle migration and mean flexibility coefficient in the extension direction compared with the intact situation (P<0.05). There was no statistically significant difference in 4 directions between the segments after the artificial disc replacement and the segments after the artificial disc replacement with cutting posterior longitudinal ligament locally (P>0.05). CONCLUSION: Artificial intervertebral disc replacement could keep the stability of the lumbar functional spine unit. There was no harmful effect of cutting posterior longitudinal ligament locally on the stability of lumbar while performing artificial intervertebral disc replacement when it is necessary.

[The application of METRx microendoscopes diskectomy system in the treatment of far lateral lumbar disc herniation].

OBJECTIVE: To introduce the METRx microendoscopes diskectomy system in the treatment of far lateral lumbar disc herniation. METHODS: Fourteen cases of far lateral lumbar disc herniation were operated with METRx from February 1999 to December 2002. Among them, the average age was 49 years old (range 41 - 55 years old), male in 10 cases, female in 4 cases. All cases were single disc herniation; L(4), 5 herniation in 6 discs, L(5)-S(1) herniation in 8 discs; foraminal disc herniation in 6 cases, extra-foraminal disc herniation in 8 cases. RESULTS: All the cases were followed up from 12 to 46 months (average 26.5 months) with the results of excellence in 10 cases, good in 3 cases, fair in 1 case and no failure case. There were no disc infection, dura laceration, nerve root injury and herniation recurrence. CONCLUSIONS: METRx is suitable for far lateral lumbar disc herniation with the advantages of minimal invasive, complete decompression of nerve root and rapid recovery. The correct approach and precise surgical technique are the key points for this operation.

[The risk factors and preventive strategies of heterotopic ossification after artificial disc replacement in lumbar spine].

OBJECTIVE: To analyze the risk factors of heterotopic (HO) ossification after total lumbar disc replacement and probe the preventive strategies for it. METHODS: The radiographs and clinical data of 78 discs in 65 patients who received artificial lumbar disc replacement (ADR) from April 1998 to December 2003 were analyzed retrospectively by two radiologists and one orthopaedic surgeon and then postoperative HO were graded according to McAfee system. The bony formations in disc spaces, time of HO were found, and range of motion (ROM) of the operated levels were measured on radiographic films. In addition, the risk factors such as preoperative peri-annulus ossification, bony endplates injuries, and subsided or mal-position of the prostheses were also analyzed by Logistic regression analysis. RESULTS: Postoperative HO was found in 10 spaces of 9 cases. Class I of HO were occurred in 7 patients at means 2.1 years postoperatively with normal range of motion preserved. Three of them turned into class II or III with 10 degrees of mean ROM in the following 2.5 years. Another 2 (2/9) cases with preoperative peri-annulus ossification had bridging trabecular bone (class III) between the endplates and 9 degrees of ROM 2 years after surgery, then turned into class IV at 6 years with 0 degrees and 4 degrees of motion in the operated levels. As the risk factors of HO, preoperative annulus ossification (2 cases), bony endplates injuries (5 cases), mal-positioned prostheses (2 cases) and subsided prostheses (2 cases) were found simultaneity with significant positive relation to HO occurred (P < 0.05). CONCLUSIONS: Factors such as preoperative ossification of annulus, endplate injuries, prosthesis subsided and mal-position would have higher risks to have HO occurred after ADR, but ROM of most affected levels are preserved. Strict control indication and avoid all above risk factors can prevent HO occurring effectively.

[Design and experiment of the pedicle aiming device for the cervical spine].

OBJECTIVE: To probe the accuracy and safety of using an aiming device in the transpedicular fixation of cervical spine. METHODS: Eight cervical specimens were obtained. We used the computed tomography (CT) to scan C3 to C7, measured the medial angle of the pedicle, and determined the location of the pedicle projecting on the articular process. Then we took the oblique X-ray film, measured the cephalic/caudal angle of the pedicle, and determined the location of the pedicle projecting on the articular process. All the specimens were equally divided into two groups. Screws of 2.8 mm x 30 mm, were used. Specimens in one group were inserted with the transpedicular screw manually, while specimens in the other one inserted with the transpedicular screw using a self-designed aiming device that can be modulate at the three dimensions according to the angles of the pedicles. RESULTS: The first group totally had 40 screws from C3 to C7. There were 13 screws in the pedicle, 9 violated the walls of the pedicle but not involved the adjunct structure, and 18 injured the important structure such as spinal cord, verteberal artery, or nerve root. In the other group, only 4 screws violated the walls of the pedicle but not involved the adjunct structure, and the others all in the pedicles. The difference was of statistical significance (P < 0.01). CONCLUSION: In the cervical spine, transpedicular fixation using an aiming device can improve the accuracy and safety during operation.

[The role of artificial disc replacement in restoring lumbar segment motion and intervertebral height].

OBJECTIVE: To investigate the role of artificial disc replacement (ADR) in restoring lumbar segment motion and intervertebral height (IH). METHODS: Seventy-five patients with intervertebral disc diseases underwent artificial disc replacement and were divided into 3 groups to be followed up for 2 years (group A, n = 32), 3 years (group B, n = 27), and 5 years (group C, n = 19) respectively. Before the operation and during the follow-up the range of motion (ROM) of the involved lumbar segments and IH were assessed. RESULTS: The mean ROM and IH of the group A were 15 degrees and 14.1 mm respectively during the follow-up 2 years after operation. The mean ROM and IH of the group B were 14.2 degrees and 13.8 mm respectively during the follow-up 2 years after the operation and 13.7 degrees and 13.4 mm respectively during the follow-up 3 years after operation. The mean ROM and IH of the group C were 9.1 degrees and 11.5 mm respectively during the follow-up 2 years after the operation and 8.8 degrees and 11.0 mm respectively during the follow-up 3 years after operation, and 8.0 degrees and 10.3 mm respectively during the follow-up 5 years after operation. No significant differences in ROM and IH were found among different groups at any time point (all P > 0.05). Malposition was found in immediately after operation in 11 patients, all of the group C. During the follow-up, 3 cases of prostheses subsidence and 3 cases of annular ossification were found. No severe complications appeared. CONCLUSION: ADR is effective in restoring the ROM and IH of vertebrae suffering from intervertebral disc diseases.

[Stimulation of insulin-like growth factor-I to chondrogenesis of engineering cartilage tissue].

OBJECTIVE: To explore the ability of insulin-like growth factor-I (IGF-I) and hyaluracan acid in prompting chondrogenesis of engineering cartilage tissue. METHODS: Human articular chondrocytes were isolated and cultured in DMEM plus 10% fetal bovine serum. They were divided into three groups: hyaluracan acid + chondrocytes + IGF-I group (IGF-I group), hyaluracan acid + chondrocytes group (cell group), hyaluracan acid group (control group). The ability of chondrogenesis was investigated by HE and toluidine blue staining, human collagen II immunohistochemistry and reverse transcription polymerase chain reaction (RT-PCR). RESULTS: Both cell group and IGF-I group could develop into cartilage tissue in the sixth week while control group could not. The number of cartilage lacuna in IGF-I group were more than that in cell group. Human collagen II immunohistochemistry showed that there were stronger positive cell in IGF-I group than in cell group, collagen II mRNA expression was more higher and collagen I mRNA expression was lower in IGF-I group than in cell group. CONCLUSION: Insulin growth factor-I can prompt chondrogenesis of engineering cartilage tissue and ameliorate the quality of engineering cartilage tissue in vitro.

[Comparative study of vertebral body stress distribution following insertion of artificial lumbar intervertebral disc].

OBJECTIVE: To study vertebral body stress distribution of normal disc, post-Diskectomy and artificial disk respectively by 3-D finite element methods, and to explore artificial intervertebral disk insertion impact on stress distribution of vertebral body. METHODS: Models of normal disk, post-Diskectomy, artificial disk and L(4 - 5) motion segment were established by using finite element software MSC. MARK, then vertebral body stress was analyzed through model of L(4 - 5) motion segment respectively. RESULTS: The vertebral body's stress was the smallest after insertion of artificial intervertebral disk (AID), and its stress distributed equally. But the stress under post-discectomy was bigger than the normal disc's in all the motion state. On the other hand, the stress distribution state of the post-discectomy changed while the spine were in different motion state, during the spine flexion, the stress in the anterior of vertebral body was the biggest; While extension, in the posterior and in right flexion state, the biggest stress was in the right. While vertical compression and rotation, the stress distributed equally. CONCLUSION: The results illustrate that the vertebral body's stress is the smallest after insertion of AID in 3 groups of all motion state, and its stress distributes equally. But the level of vertebral body stress increases after discectomy comparing with the normal group. In generally, it is much more reasonable that the disc is reconstructed with AID because of the biomechanical effect on vertebral body made by AID insertion.