BACKGROUND:Preliminary experiments have demonstrated that the expression of Notch-1 in the degenerated intervertebral disc was increased. However, the role of Notch-1 in the nucleus pulposus-like cel differentiation of mesenchymal stem cel s remains unclear.
OBJECTIVE:To investigate the bone marrow mesenchymal stem cel s in suppressing the degeneration of intervertebral discs after Notch1 gene knockout.
METHODS:(1) Bone marrow mesenchymal stem cel s were isolated from the femur bone of four New Zealand rabbits weighing 0.4-0.5 kg, under deep anesthesia, and then purified with discontinuous gradient density centrifugation method. (2) Notch1 shRNAs and blank plasmid shRNA were designed, synthesized, and transiently transfected into these mesenchymal stem cel s, and the differentiation of mesenchymal stem cel s was induced with transforming growth factor beta-1. (3) Ten New Zealand rabbits weighing 1.0-1.5 kg were involved in this study. The rabbits’ intervertebral discs in L3-4, L4-5 and L5-6 were stabbed by a needle, and nucleus pulposus tissue was harvested for modeling. The cel s were divided into blank plasmid transfected with transforming growth factor beta-1 group, shRNA-Notch-1 plasmid transfected with transforming growth factor beta-1 group, and non-transfected treated with transforming growth factor beta-1 group. Two weeks later the treated cel s were transplanted into L3-4, L4-5 and L5-6, respectively.
RESULTS AND CONCLUSION:(1) Four weeks after the cel transplantation, the signal intensity of T2 weighted images in the L3-4 (non-transfection group) and L5-6 (blank plasmid group) discs was increased by magnetic resonance imaging, and the significant difference was found in L4-5 discs (shRNA-Notch-1 plasmid group) in comparison with other two groups (P<0.05). (2) Toluidine blue staining showed that, the expression of proteoglycan in the L4-5 discs (shRNA-Notch-1 plasmid group) was significantly higher than that in L3-4 (non-transfection group) and L5-6 (blank plasmid group) discs. (3) Reverse transcription-polymerase chain reaction and western blot assay showed that, the expression of col agen II and proteoglycan mRNA and protein in the L4-5 discs (shRNA-Notch-1 plasmid group) were significantly increased compared with L3-4 (non-transfection group) and L5-6 (blank plasmid group) discs. Transplantation of bone marrow mesenchymal stem cel s of Notch-1 gene knockout rabbits can effective restore the degenerated intervertebral discs.

BACKGROUND: Whether the proximal tibial osteotomy in Mongolia populations has difference with other populations at home and abroad remains unclear.OBJECTIVE: To analyze the anatomical characters of the proximal tibial osteotomy in Mongolia populations in the northern region of China by measuring the relevant linear parameters.METHODS: Thirty-eight healthy Mongolia populations were selected, and their bilateral knee joints were scanned by CT.The original data were exported in DICOM format. Mimics software was used to reconstruct the knee three-dimensional model. The tibial data stored in STL format were imported into 3-matic software, showing the medial surface of the tibia,and 6 mm below the medial tibial plateau maintaining 7° posterior slop was subjected to total hip arthroplasty osteotomy.Subsequently, the relevant parameters were measured.RESULTS AND CONCLUSION: (1) The left tibia transverse diameter was (79.99±3.70) mm, and the right was (80.25±4.01) mm. The left anteroposterior diameter was (52.27±3.07) mm, and the right was (51.75±2.40) mm. The anteroposterior diameter of medial tibia was (55.40±2.00) mm (left), and (56.67±2.47) mm (right); the lateral was (49.84±2.78) mm (left), and (49.58±2.80) mm (right). (2) In Mongolian populations, the linear parameters showed no significant differences between two sides of the proximal tibial osteotomy (P > 0.05). The anteroposterior diameter of medial tibia was longer than that of lateral one (P > 0.05). The linear parameters of the proximal tibial osteotomy in male were significantly larger than those in female (P < 0.05). There were differences in the linear parameters of the proximal tibial osteotomy between Mongolian populations and other populations. (3)These results indicate that there are significant differences in the anatomical morphology of the tibial plateau between western and eastern countries.Besides, the geometric parameters of the tibial plateau may be different in different ethnic groups and regions. It is necessary to use the digital orthopedic technique to investigate and analyze the large sample data of different ethnic groups in different regions.