Observation of dendrite osteocytes of mice at different developmental stages using Ploton silver staining and phalloidin staining / 南方医科大学学报

OBJECTIVE@#To assess the value of Ploton silver staining and phalloidin-iFlour 488 staining in observation of the morphology of osteocyte dendrites of mice at different developmental stages.@*METHODS@#The humerus and femurs were harvested from mice at 0 (P0), 5 (P5), 15 (P15), 21 (P21), 28 (P28), and 35 days (P35) after birth to prepare cryo-sections and paraffin sections. HE staining of P35 mouse femur sections served as a reference for observing osteocytes in the trabecular bone and cortical bone. The humeral sections at different developmental stages were stained with Ploton silver staining to observe the morphology of osteocytes and canaliculi, and the canalicular lengths in the cortical and trabecular bones of the humerus of the mice in each developmental stage were recorded. The cryo-sections of the humerus from P10 and P15 mice were stained with phalloidin iFlour-488 to observe the morphology of osteocytes and measurement of the length of osteocyte dendrites in the cortical bone.@*RESULTS@#In the trabecular bone of the humerus of P0-P15 mice, Ploton silver staining only visualized the outline of the osteocytes, and the morphology of the canaliculi was poorly defined. In P21 or older mice, Ploton silver staining revealed the morphology of the trabecular bone osteocytes and the canaliculi, which were neatly arranged and whose lengths increased significantly with age (P21 @*CONCLUSIONS@#Mouse osteocyte dendrites elongate progressively and their arrangement gradually becomes regular with age. Ploton silver staining can clearly visualize the morphology of the osteocytes and the canaliculi in adult mice but not in mice in early stages of development. Phalloidin iFlour-488 staining for labeling the cytoskeleton can be applied for mouse osteocytes at all developmental stages and allows morphological observation of mouse osteocytes in early developmental stages.

An optimized method for embedding undecalcified mouse tibias in plastic blocks / 南方医科大学学报

OBJECTIVE@#To optimize the method for embedding multiple undecalcified mouse tibias in plastic blocks, improve the efficiency and stability of plastic embedding and reduce the detachment rate of plastic slides.@*METHODS@#Thirty undecalcified tibias from 15 B6 mice were used for plastic embedding after calcein labeling, fixation, dehydration and infiltration. The tibias were embedded in cylindrical plastic blocks with a diameter of 4 mm. For each bone, the 1/4 proximal tibia was cut off, and the remaining 3/4 was used for re-embedding. Five bones were embedded in a single block with each bone standing closely on the surface of a flat plate. The samples were randomized into control and experimental groups in all the processes of embedding, sectioning and staining. In the 3 groups with modified embedment, flowing CO was added into the embedding solution, embedding solution was applied to the section surface, and the slides were heated at 95 ℃ for 15 min. The polymerization time, slide detachment rate, bone formation and osteoblast parameters were analyzed.@*RESULTS@#We prepared 6 plastic blocks, each containing 5 tibias, whose cross sections were on the same plane. The blocks were completely polymerized and suitable for sectioning. Flowing CO into the embedding solution reduced the polymerization time and increased the rate of complete polymerization. Application of the embedding solution on the section surface significantly reduced the detachment rate of the sections ( < 0.05) without affecting bone formation analysis ( > 0.05). Heating the slides significantly lowered the detachment rate of the sections ( < 0.05) without affecting osteoblast analysis ( > 0.05).@*CONCLUSIONS@#The optimized method allows effective embedding of multiple undecalcified mice tibias in the same block and can be an ideal method for histological analysis of undecalcified bones.

Preliminary clinical effects of total knee arthroplasty with iASSIST navigation system / 中华骨科杂志

Objective To explore the application value of iASSIST portable navigation in total knee arthroplasty.Methods Seventy-four patients with knee osteoarthritis from April 2016 to April 2017 were retrospectively recruited.Thirty-seven patients (37 knees) underwent TKA with iASSIST navigation,while 37 patients (37 knees) underwent conventional TKA.Five parameters were measured on the weight-bearing radiographs at six months after TKA,including mechanical axis (MA),mechanical lateral distal femoral angle (mLDFA),mechanical medial proximal tibial angle (mMPTA),sagittal femoral component angle (sFCA) and sagittal tibial component angle (sTCA).Duration of operation,blood loss volume,postoperative hospital day,Western Ontario and McMaster Universities (WOMAC) osteoarthritis index,Knee Society Score (KSS) clinical score and functional score at 6 weeks,12 weeks and 24 weeks after surgery were also recorded.Results The accuracy of MA (180.85°±0.88° versus 182.23°±1.09° in the conventional group,P＜0.05),mLDFA (90.52° ±0.78° versus 91.09° ±0.96° in the conventional group,P＜0.05),and mMPTA (90.34°± 1.25° versus 91.13°± 1.46° in the conventional group,P＜0.05) was improved significantly in navigation group.The WOMAC osteoarthritis index at 6 weeks postoperatively in the navigation group and in the conventional group were 58.54±1.45 and 56.54± 1.77 respectively.The KSS clinical score in the navigation group and in the conventional group were 53.14± 1.13 and 49.35± 1.11 respectively.The KSS functional score in two groups were 61.24± 1.30 and 59.81 ± 1.29 respectively (P＜0.05).The WOMAC osteoarthritis index at 12 weeks postoperatively in the navigation group and in the conventional group were 43.54± 1.19 and 41.92± 1.42 respectively.At 12 weeks,the KSS clinical score in two groups were 67.11 ± 1.51 and 62.08± 1.46 respectively.The KSS functional score in two groups were 68.14±1.11 and 66.38±1.26 respectively (P＜0.05).The blood loss volume in the navigation group and in the conventional group were 113.11±57.29 ml and 147.57±68.77 ml respectively (P＜0.05).There were no significant difference in the duration of operation,postoperative hospital day,WOMAC osteoarthritis index,knee clinical score and functional score at 24 weeks postoperatively between two groups (P＞0.05).Conclusion More accurate restoration in mechanical axis and optimal implantation can be achieved with the help of iASSIST navigation.This navigation system can also achieve better knee function in the early stage after TKA.

Bone regenerationvia a novel honeycomb-like polycaprolactone-calcium silicate crystal compound scaffold in extreme-sized cranial defects / 中国组织工程研究

BACKGROUND:Polycaprolactone as a polymer material has poor biocompatibility, and needs to be combined with other natural biological materials to increase biocompatibility, thereby promoting tissue regeneration.OBJECTIVE:To develop a novel honeycomb-like polycaprolactone-calcium silicate crystal compound scaffold, and observe its osteogenic effects in Sprague-Dawley rats with skull defects.METHODS: Eighteen Sprague-Dawley rats were used to make skull defect models and randomized into three groups: blank control group with no implantation, control group with implantation of normal polycaprolactone-calcium silicate crystal compound scaffold, and experimental group with implantation of the novel honeycomb-like polycaprolactone- calcium silicate crystal compound scaffold. Six weeks after implantation, bone regeneration effect in the defect region measuredvia X-ray scanning, Micro-CT three-dimensional reconstruction, and histological analysis.RESULTS AND CONCLUSION: (1) X-ray scan: in all the rats, the size of bone defect was reduced, the fracture line became vague, and the marginal bone density was increased. The percentage of new bone area was highest in the experimental group, successively followed by the control group and blank control group. (2) Micro-CT three-dimensional reconstruction: new bones in the blank control group were mainly distributed on the both sides of the defect, but those in the control and experimental groups distributed in the defect region. The bone regeneration capacity was ranked as follows: experimental group > control group > blank control group (P < 0.05). (3) Histological analysis: new bone ingrowth was visible in all the three groups to different extents. Compared with the other two groups, new bone formation and microvessel density were significantly higher in the experimental group (P < 0.05). To conclude, this novel honeycomb-like polycaprolactone-calcium silicate crystal compound scaffold can obviously promote bone formation in the skull defect region.