ObjectiveTo explore the biological functions of Kip1 ubiquitylation-promoting complex 2 (KPC2) in the repair process of spinal cord injury (SCI) by studying the expression and cellular localization of KPC2 in rat SCI models. MethodsFifty-six adult Sprague-Dawley rats were randomly divided into 2 groups: in the control group (n=7), simple T9 laminectomy was performed;in the experimental group (n=49), the SCI model was established at T9, 7 rats were used to detect follow indexs at 6 hours, 12 hours, 1 day, 3 days, 5 days, 7 days, and 14 days after SCI. Western blot analysis was used to detect the protein expressions of P27kip1, KPC2, CyclinA and proliferating cell nuclear antigen (PCNA) after SCI. Immunohistochemistry was used to observed the cellular localization of KPC2 after SCI, double-labeling immunofluorescence staining to observe the co-localization of KPC2 with neuronal nuclei (NeuN), glial fibrillary acidic protein (GFAP) and PCNA. in vitro astrocytes proliferation model was used to further validate these results, Western blot to detect KPC2, P27kip1, and PCNA expressions. The interaction of P27kip1, KPC1, and KPC2 in cell proliferation was analyzed by co-immunoprecipitation. ResultsThe Western blot analysis showed a significant down-regulation of P27kip1 and a concomitant up-regulation of KPC2, CyclinA, and PCNA after SCI. Immunohistochemistry staining revealed a wide distribution of KPC2 positive signals in the gray matter and white matter of the spinal cord. The number of KPC2 positive cells in the experimental group was significantly higher than that in the control group (t=10.982, P=0.000). Double-labeling immunofluorescence staining revealed the number of KPC2/NeuN co-expression cells in the gray matter of spinal cord was (0.43±0.53)/visual field in the control group and (0.57±0.53)/visual field in the experimental group, showing no significant difference (t=0.548, P=0.604);in the white matter of spinal cord, the number of KPC2/PCNA co-expression cells was (3.86±0.90)/visual field in the control group and (0.71±0.49)/visual field in the experimental group, showing significant difference (t=7.778, P=0.000). And then, the number of KPC2/PCNA co-expression cells were (0.57±0.53)/visual field in the control group and (5.57±1.13)/visual field in the experimental group, showing significant difference (t=8.101, P=0.000). Concomitantly, there was a similar kinetic in proliferating astrocytes in vitro. The Western blot analysis showed a significant down-regulation of P27kip1 and a concomitant up-regulation of KPC2 and PCNA after serum stimulated. Co-immunoprecipitation demonstrated increased interactions between P27kip1, KPC1, and KPC2 after stimulation. ConclusionThe up-regulated expression of KPC2 after SCI is related to the down-regulation of P27kip1, this event may be involved in the proliferation of astrocytes after SCI.
Objective To study digitize design of custom-made radial head prosthesis and to verify its matching precision by the surgery of preoperative three-dimensional (3-D) virtual replacement. Methods Six healthy adult volunteers (3 males and 3 females, aged 25-55 years with an average of 33 years) received slice scan of bilateral elbow by Speed Light 16-slice spiral CT. The CT Dicom data were imported into Mimics 10.0 software individually for 3-D reconstruction image, and the left proximal radial 3-D image was extracted, the mirror of the image was generated and it was split into 2 pieces: the head and the neck. The internal diameter and the length of the radial neck were obtained by Mimics 10.0 software measurement tools. In Geomagic Studio 12 software, the radial head was simulated to cover the cartilage surface (1 mm thickness) and generated to an entity. In UG NX 8.0 software, the stem of prosthesis was designed according to the parameters above and assembled head entity. Each custom-made prosthesis was performed and verified its matching precision by the surgery of preoperative 3-D virtual replacement. Results Comparing the morphology of 6 digitize custom-made prostheses with ipsilateral radial heads by the 3-D virtual surgery, the error was less than 1 mm. The radial head prosthesis design on basis of the contralateral anatomy was verified excellent matching. Conclusion The 3-D virtual surgery test and the digitized custom-made radial head prosthesis will be available for clinical accurate replacement.