BACKGROUND:Carboxymethylated chitosan is shown to promote some kinds of cells proliferation, but its effects on proliferation of Schwann cells need further studies.
OBJECTIVE:To investigate the effects of carboxymethylated chitosan on proliferation of Schwann cells and expression of nuclear factor-κB in cultured Schwann cells.
METHODS:Schwann cells from Sprague-Dawley rats at logarithmic growth phase were seeded in 96-wel plates, and cultured respectively with PBS, 0, 10, 50, 100, 200, 500, 1 000 mg/L carboxymethyl chitosan for 24 hours. cellproliferation was detected using the cellcounting kit-8 assay. After trypsin digestion, Schwann cells from Sprague-Dawley rats at logarithmic growth phase were used to prepare cellsuspensions, which were seeded in 6-wel cellculture plates and cultured respectively with 50, 100 and 200 mg/L carboxymethyl chitosan and PBS for 24 hours. Then, 5-bromo-2-deoxyuridine, real-time PCR and western blot assay were performed.
RESULTS AND CONCLUSION:cellcounting kit-8 and 5-bromo-2-deoxyuridine detection results showed that carboxymethyl chitosan at 50-1000 mg/L, especial y at 200-500 mg/L, could promote Schwann cellproliferation. Real-time PCR and western blot results showed 50-200 mg/L carboxymethyl chitosan could promote nuclear factorκB mRNA and protein expression in Schwann cells in a dose-dependent manner, suggesting carboxymethyl chitosan can promote Schwann cellproliferation and expression of nuclear factor-κB in Schwann cells cultured in vitro.

BACKGROUND:Recently, non-fusion technology representing as artificial cervical disc replacement continues to improve. On the basis of reconstruction of disc structure and function of involved segments, cervical spine structure of surgery area segment is significantly close to dynamic and static load stress distribution required by natural physiological systems. It effects are apparent in protecting intervertebral facet joints of degenerated segment and structure and function of the cervical spine of adjacent segments and in maintaining cervical dynamic stability, which presented obvious methodological strengths compared with segmental fusion technology.
OBJECTIVE:To evaluate the clinical outcomes of anterior cervical discectomy and fusion and Bryan artificial cervical disc replacement in the treatment of single-level cervical spondylotic myelopathy or radiculopathy.
METHODS:A total of 43 middle and old age patients with single-level cervical spondylotic myelopathy or radiculopathy, who were treated from March 2010 to March 2012, were enrol ed in this study. They were randomly assigned to anterior cervical discectomy and fusion group (fusion group) and Bryan artificial cervical disc replacement group. Range-of-motion of cervical overal and adjacent intervertebral area near the intervertebral space was observed with radiography. During fol ow-up, postoperative recovery of neurological function was evaluated using Japanese Orthopaedic Association scale, visual analog scale and neck disability index.
RESULTS AND CONCLUSION:None patients experienced complications of neurovascular injury during and after the surgery. Range-of-motion of postoperative overal cervical vertebra and adjacent joint was improved in the Bryan artificial cervical disc replacement group compared with the fusion group. Neurological function was apparently improved after surgery in each group. At 3 months after surgery, scores of Japanese Orthopaedic Association, visual analog scale and neck disability index were significantly improved in the Bryan artificial cervical disc replacement group compared with the fusion group (P<0.05). During final fol ow-up, there were significant differences in visual analog scale scores between the two groups. Japanese Orthopaedic Association scale score and neck disability index score were similar between the two groups. During fol ow-up, no prosthesis sinking, displacement or heterotopic ossification were detected. These data indicated that artificial cervical disc replacement could effectively keep the range of motion of cervical segments and protect disc degeneration of adjacent segment. Mid-term fol ow up obtained similar improvement of neurological function of fusion surgery. The moderate-term and short-term efficacies of non-fusion technology were better than fusion technology in the treatment of single-level cervical spondylopathy.

Objective To study the effects of carboxymethylated chitosan (CMCS) to nitric oxide (NO)-induced apoptosis on rat chondrocytes,and explore p38MAPK signal transduction pathway in the process and its mechanism.Methods The rat articular cartilage cells were cultured in vitro,collagen type-2 (collagen-2) immunohistochemical staining was used to identify the cartilage cells.The model of chondrocyte apoptosis was built by different concentrations of sodium nitroprusside (SNP) induction.The cells were divided into the control group,the SNP treated group SNP+CMCS treated group,and the SNP+p38 MAPK inhibitor SB203580 treated group.The apoptotic rate of chondrocytes was calculated by FCM,apoptotic nuclei was identified by Hoechst33342 stain,the mitochondrial membrane potential changes was detected by Rhodamine123 (Rho123) stain,the expression of p38 and p-p38 were detected by Western blotting analysis.Results 1-3 mmol/L SNP could induce chondrocyte apoptosis,the apoptotic rate was increased with the SNP increasing,the most obvious apoptosis was occurred in 3 mmol/L SNP treated chondrocytes,which was 69.8％ (P＜0.05).SNP could increase the nuclear fragmentation of chondrocytes,the cells with nuclear fragmentation was significantly higher than that in the control group.SNP could reduce mitochondrial membrane potential in chondrocytes,which decreased significantly compared with the control group.SNP could increase the p-p38 expression in chondrocytes,which was 4.3 times compared to the control group.CMCS of different concentrations could reduce the apoptotic rate of SNP-induced chondrocytes,which was 51.0％,29.9％ and 15.2％,which was decreased significantly (P＜0.05) when compared with 3 mmol/L SNP induced group,CMCS decreased the cells number of SNP-induced nuclear fragmentation.CMCS increased the mitochondrial membrane potential in SNP-induced chondrocytes.CMCS reduced the expression levels of p-p38 in SNP-induced chondrocytes.Conclusion CMCS has protective effect on SNP-induced apoptosis of chondrocytes.This process is completed by inhibiting the activity of p38 MAPK signal pathway.