Fluorescein angiography(FA)was performed in 31 pigmented rebbits.The angiograms were evaluated as prints and as negative film under a light microscope.The patterns of retinal pigment epithelial(RPE)cells were studied by scaning electron microscopy and fluorescein light one,compared with other rabbits belonging to the same species.In 58 eyes,we observed the hexagonal pattern of RPE cell.It showed central hypofluorescent area surrounded by hyperfluorescent rim,which was easily seen away from the medullary rays by three or more disc diameters and became larger in the periphery than that in the posterior pole.There were no finding in four lightly pigmented eyes. （Chin J Ocul Fundus Dis,1994,10:226-228）
Objective To investigate the effect of Kartogenin (KGN) combined with adipose-derived stem cells (ADSCs) on tendon-bone healing after anterior cruciate ligament (ACL) reconstruction in rabbits. Methods After the primary ADSCs were cultured by passaging, the 3rd generation cells were cultured with 10 μmol/L KGN solution for 72 hours. The supernatant of KGN-ADSCs was harvested and mixed with fibrin glue at a ratio of 1∶1; the 3rd generation ADSCs were mixed with fibrin glue as a control. Eighty adult New Zealand white rabbits were taken and randomly divided into 4 groups: saline group (group A), ADSCs group (group B), KGN-ADSCs group (group C), and sham-operated group (group D). After the ACL reconstruction model was prepared in groups A-C, the saline, the mixture of ADSCs and fibrin glue, and the mixture of supernatant of KGN-ADSCs and fibrin glue were injected into the tendon-bone interface and tendon gap, respectively. ACL was only exposed without other treatment in group D. The general conditions of the animals were observed after operation. At 6 and 12 weeks, the tendon-bone interface tissues and ACL specimens were taken and the tendon-bone healing was observed by HE staining, c-Jun N-terminal kinase (JNK) immunohistochemical staining, and TUNEL apoptosis assay. The fibroblasts were counted, and the positive expression rate of JNK protein and apoptosis index (AI) were measured. At the same time point, the tensile strength test was performed to measure the maximum load and the maximum tensile distance to observe the biomechanical properties. Results Twenty-eight rabbits were excluded from the study due to incision infection or death, and finally 12, 12, 12, and 16 rabbits in groups A-D were included in the study, respectively. After operation, the tendon-bone interface of groups A and B healed poorly, while group C healed well. At 6 and 12 weeks, the number of fibroblasts and positive expression rate of JNK protein in group C were significantly higher than those of groups A, B, and D (P<0.05). Compared with 6 weeks, the number of fibroblasts gradually decreased and the positive expression rate of JNK protein and AI decreased in group C at 12 weeks after operation, with significant differences (P<0.05). Biomechanical tests showed that the maximum loads at 6 and 12 weeks after operation in group C were higher than in groups A and B, but lower than those in group D, while the maximum tensile distance results were opposite, but the differences between groups were significant (P<0.05). Conclusion After ACL reconstruction, local injection of a mixture of KGN-ADSCs and fibrin glue can promote the tendon-bone healing and enhance the mechanical strength and tensile resistance of the tendon-bone interface.
The pathogensis of choroidal vascular changes in traumatic rtinopethy remains uncertain.We performed scanning electron micrmcopie (SEM) observation of methyl methalerylare vascular corrosion casts in a rabbi model with severe retinal contusion. Areas of filling defects in corrosion casts of the choriocapillaries, correspending to the areas of impact retinal lesions were noted in the traumatized eyes one to 28 days after trauma.No neovascularization was found in the eyes 56 days after trauma. The results confirm that obstruction and disappearance of involved choriocapillaries are the main changes of choroidal vasculatrue in severe blunt tram. The changes may be associated with continuous necrosis, of the photoreceptors 4 weeks after injury. （Chin J Ocul Fundus Dis,1993,9:5-7）
Objective To study the mechanism of restenosis of the vein graft and the effect of the grafting injury to the vein graft. Methods One side of the 36 healthy rabbits was randomly chosen as the V-A group, and on the side a 1.5cmlong femoral vein was obtained, and an 0.5-cm-long segment of the obtained femoral vein was separated as the control group. The remaining 1-cm-long femoral vein was inverted and was autogenously implanted into the femoral artery on the same side of the rabbit. The other side of the rabbits was chosen as the V-V group, and on this side a 1-cm-long femoral vein was obtained ex vivo and then was sutured in situ. The vein grafts on both sides were harvested 4 weeks after operation. The specimens from the harvested vein grafts were stained with HE and theelastic fiber Victoria blue for an observation on the histological changes in the walls of the vein grafts, and the specimens were also stained by the immunohistochemistry of the proliferating cell nuclear antigen (PCNA) for an observation on the wall cell proliferation of the vein grafts. The changes in the ultrastructure of the proliferated wall cells of the vein grafts were observed under electron microscope. The two sides of the rabbits were compared. Results The smooth muscle cells of the media developed hyperplasia, but theintima and the media remained unchanged in their thickness (3.50±0.41 μm, 12.23±1.59 μm) in the V-V group, with no difference when compared with the control group (3.40±0.37 μm, 12.14±1.62 μm); however, when compared with the V-A group (25.60±3.21 μm, 21.30±2.47 μm),there was a significant difference in the thickness (Plt;0.01). There were no cells positive for PCNA by the immunohistochemistry examination in the control group. The cells positive for PCNA were found in the intima and the media in both the V-V group and the V-A group; however, the percentageof the cells positive for PCNA in the intima and the media was significantly greater in the V-A group than in the V-V group (16.4%±1.9% and 36.5%±3.7% vs 5.9%±1.3% and 23.4%±3.4%, Plt;0.01). In the V-V group, the endothelial cell could be observed under transmis-sion electron microscope, which was flat and had a processlike villus at its free end, and the endothelial cells were closely arranged andhad hyperplasia of the smooth muscle cells in the media. But in the V-A group,the endothelial cells had an obvious hyperplasia with an irregular shape and a widened space between the cells, and in the intima a great amount of the smooth muscle cells could be observed, which had a broken basement membrane. The smooth muscle cells also had an obvious hyperplasia in the media. The shape and alignment of the endothelial cells in the control group were similar to those in the V-V group, but the hyperplasia of the smooth muscle cells was not observed in the media. Conclusion The grafting injury can cause hyperplasia ofthe vascular wall cells, and if the hemodynamics is changed simultaneously, more serious hyperplasia and cell migration can be observed from the media to the intima, resultingin restenosis of the blood vessels. So, if we can reduce the grafting injury and improve the microcirculation of the vein graft, we may find out the methods ofpreventing restenosis of the vein graft. The animal model of the V-V graftcan help to understand the mechanism of restenosis of the vein graft.
PURPOSE:To investigate the approaches for transplanting retinal pigment epithelium. METHODS,Retinal pigment epithelial eells(RPR)of pigmented rabbits' eyes prepared by rotalne preparation of our institute,were transphmted in 18 unpigmemed rabbits'eyes.Eight eyes were undergone outer approach, i.e., transplanting the RPR cells to the subretinal space of recipient eyes by way of perforating sclera and choroid;while 10 eyes were undergone internal approach by way of the routine procedure of vitrectomy with making artificial localized retinal delachment. Light and transmisskm electrone microscopy examination were done at 10th, goth, 40th and 90th day after the operation. RESULTS: In internal approach group,tbe operated eyes,revealed no difference in thickness of the neural retinal layer in transplanted and non-transplanted area 40 days after operation tinder light microscope. Transmission electrone microscopy revealed postoperatively the transplanted RPE cells attached to the Brucb's membrane and the outer segments of photoreeeplive ceils located at a normal position at the 40th dayland the secondary lysozymes with engulfed outer segment were found in the Iransplamed cells at the 90th day. Tbe outer approached operations in eight eyes were failed owing to ehoroid hemorrhage or perforation of retina. CONCLUSION:The internal appraach procedure is much effebtive and practical for transplantation of RPE cells. （Chin J Ocul Fundus Dis,1997,13:160-162）
The comparison made between two experimental models with obstructive jaundice, which were newly established reversible model and traditional bile duct ligation and internal drainage model, showed that the new model was superior to the traditional one. This study suggests that the new model would be an ideal model, which could replace the traditional one for studying obstructive jaundice.
目的:探讨锝99-亚甲基二膦酸盐(99Tc-MDP,商品名云克)对兔空腹血糖的影响。方法:实验兔30只随机分为99Tc-MDP组,地塞米松组,生理盐水对照组。分别测定给药前,给药后3 d、7 d、14 d、21 d五个不同阶段空腹血糖值。检测结果采用SPSS软件进行方差分析,作均数差异的显著性检验。结果:与生理盐水对照组比较,使用地塞米松14 d后,兔空腹血糖明显升高,且差异具有统计学意义(Plt;0.05)。但99Tc-MDP组血糖无升高,且与生理盐水对照组比较无显著性差异(Pgt;0.05)。结论:地塞米松大剂量使用可导致兔空腹血糖升高,而99Tc-MDP未导致兔空腹血糖升高
Objective To investigate the effect of ultrasonic irradiation time on enhanced green fluorescent protein (EGFP) gene transfection efficiency and local tissue in bone defects using ultrasound-mediated microbubble destruction. Methods Thirty 3-month-old New Zealand rabbits (2.5-3.0 kg in weight) were randomly divided into 5 groups (n=6) and bone defect models were made on the right ulna. At 10 days after modeling, suspension of microbubbles and EGFP plasmids were locally injected (0.3 mL/kg) and then ultrasound was performed on defect at a frequency of 1 MHz, a intensity of 0.5 W/cm2, and a duty ratio of 20% for 1, 2, 3, 4, and 5 minutes respectively (in 1, 2, 3, 4, and 5 minutes groups respectively). The survival condition was observed. Rabbits were sacrificed for gross observation at 7 days after transfer. The gene expression was observed by fluorescence staining. HE staining and transmission electron microscopy were used to observe the local tissue damage. Results The animals all survived. New soft tissue formed in bone defects area at 1 week after transfer, the surrounding muscle tissue was partly filled in it. Green fluorescence expression was observed in all rabbits. The expression was the strongest in 2 minutes group, and was the weakest in 1 minute group. The absorbance (A) value showed significant differences when compared 1 minute and 2 minutes groups with other groups (P<0.05), but no significant difference was found between 3, 4, and 5 minutes groups (P>0.05). Tissue damage was observed in all groups and it was aggravated with the increase of irradiation time. Conclusion EGFP transfection efficiency in bone defect by ultrasound-mediated microbubble destruction is related to irradiation time. EGFP gene can be efficiently transfected without obvious toxicity at 1 MHz, 0.5W/cm2, and duty ratio of 20% for 2 minutes in bone defects of rabbits.
Objective To give a prel iminary experimental evidence and to prove chitosan and allogeneic morsel ized bone as potential bone substitutions in repairing rabbit radius segmental defect. Methods Chitosan and allogeneic morsel ized bone were mixed with various ratios (1 ∶ 5, 1 ∶ 10, 1 ∶ 25, 1 ∶ 50, and 1 ∶ 100). After preparation, the physicaland chemical properties of the composites were prel iminary detected; the composites at the ratios of 1 ∶ 50 and 1 ∶ 25 had good physical and chemical properties and were used for the animal experiment. The radius segmental defects of 15 mm in length were made in 50 adult New Zealand white rabbits (weighing 2.5-3.0 kg), then the animals were divided into 2 groups. In groups A and B, chitosan/allogeneic morsel ized bone composites were implanted at the ratio of 1 ∶ 50 and 1 ∶ 25, respectively. After 1, 2, 4, 8, and 12 weeks of operation, the gross, histological, immunohistochemical observations were performed. Before the rabbits were sacrified, X-ray films were taken; the serum calcium and alkal ine phosphatase (ALP) concentration were measured; and the biomechanical measurement was carried out at 12 weeks. Results The results of gross observation were essentially consistent with those of the X-ray films. The histological observation showed that the bone formation was earl ier in group A than in group B; the amount of new bone formation in group A was more than that in group B; and the bone forming area in group A was bigger than that in group B (P lt; 0.05) at 4 and 8 weeks after operation. The immunohistochemical staining showed that vascular endothel ial growth factor and insul in-l ike growth factor receptor II proteins expressed in the cytoplasm of 2 groups after 4 and 8 weeks, and the expression in group A was higher than that in group B (P lt; 0.05). There was no significant difference in the serum calcium concentration between 2 groups at each time point (P gt; 0.05). After 4 and 8 weeks, the ALP concentration in group A was significantly higher than that in group B (P lt; 0.05). After 12 weeks, the radius maximum bending loads of groups A and B were (299.75 ± 27.69) N and (278.54 ± 17.09) N, respectively, showing significant difference (t=4.045,P=0.002). Conclusion The composite of chitosan and allogeneic morsel ized bone has good osteogeneic activity and can beused as a bone tissue engineering scaffold, and the optimum ratio of chitosan to allogeneic morsel ized bone was 1 ∶ 50.
ObjectiveTo evaluate the effect of a novel micro-arc oxidation (MAO) coated magnesium-zinc-calcium (Mg-Zn-Ca) alloy scaffold/autologous bone particles to repair critical size bone defect (CSD) in rabbit and explore the novel scaffold in vivo corrosion resistance and biocompatibility.MethodsSeventy-two New Zealand white rabbits were randomly divided into 3 groups (n=24), group A was uncoated Mg-Zn-Ca alloy scaffold group, group B was 10 μm MAO coated Mg-Zn-Ca alloy scaffold group, and group C was control group with only autologous bone graft. The animals were operated to obtain bilateral ulnar CSD (15 mm in length) models. The bone fragment was removed and minced into small particles and were filled into the scaffolds of groups A and B. Then, the scaffolds or autologous bone particles were replanted into the defects. The animals were sacrificed at 2, 4, 8, and 12 weeks after surgery (6 rabbits each group). The local subcutaneous pneumatosis was observed and recorded. The ulna defect healing was evaluated by X-ray image and Van Gieson staining. The X-ray images were assessed and scored by Lane-Sandhu criteria. The percentage of the lost volume of the scaffold (ΔV) and corrosion rate (CR) were calculated by the Micro-CT. The Mg2+ and Ca2+ concentrations were monitored during experiment and the rabbit liver, brain, kidney, and spleen were obtained to process HE staining at 12 weeks after surgery.ResultsThe local subcutaneous pneumatosis in group B was less than that in group A at 2, 4, and 8 weeks after surgery, showing significant differences between 2 groups at 2 and 4 weeks after surgery (P<0.05); and the local subcutaneous pneumatosis was significantly higher in group B than that in group A at 12 weeks after surgery (P<0.05). The X-ray result showed that the score of group C was significantly higher than those of groups A and B at 4 and 8 weeks after surgery (P<0.05), and the score of group B was significantly higher than that of group A at 8 weeks (P<0.05). At 12 weeks after surgery, the scores of groups B and C were significantly higher than that of group A (P<0.05). Meanwhile, the renew bone moulding of group B was better than that in group A at 12 weeks after surgery. Micro-CT showed that ΔV and CR in group B were significantly lower than those in group A (P<0.05). Van Gieson staining showed that group B had better biocompatibility and osteanagenesis than group A. The Mg2+ and Ca2+ concentrations in serum showed no significant difference between groups during experiments (P>0.05). And there was no obvious pathological changes in the liver, brain, kidney, and spleen of the 3 groups with HE staining at 12 weeks.ConclusionThe MAO coated Mg-Zn-Ca alloy scaffold/autologous bone particles could be used to repair CSD effectively. At the same time, 10 μm MAO coating can effectively improve the osteanagenesis, corrosion resistance, and biocompatibility of Mg-Zn-Ca alloy scaffold.