Objective To detect the cell density, apoptotic rate, and the expressions of BNIP3 in nucleus pulposus of degenerative intervertebral disc of rabbits, so as to further understand the mechanism of intervertebral disc degeneration. Methods Thirty male New Zealand white rabbits, aging 3 months and weighing (2.3 ± 0.2) kg, were divided into sham operation group (control group, n=10) and intervertebral disc degeneration model group (experimental group, n=20). Interbertebral disc degeneration models were establ ished by puncture of L3,4, L4,5, and L5,6 intervertebral discs in the experimental group; intervertebral discs were exposed only and then sutured in the control group. The degree of intervertebral disc degeneration was evaluated according to Pfirrmann classification by MRI at 4 and 8 weeks after establ ishing models. Apototic cells were determined by TUNEL and histological methods, and the immunohistochemical staining was performed to detect the expressions of BNIP3 in nucleus pulposus of intervertebral disc. Results MRI examination showed that the signal intensity decreased gradually at 4 and 8 weeks in the experimental group. There wassignificant difference in the degree of intervertebral disc degeneration between at 4 weeks and at 8 weeks in the experimental group (P lt; 0.05). The histological observation and TUNEL test showed that high density of nucleus pulposus cells and only a few apoptotic cells were observed in the control group; at 4 and 8 weeks, the density of nucleus pulposus cells decreased gradually with more apoptotic cells in the experimental group. There were significant differences in the nucleus pulposus cell density and positive rate of TUNEL staining between 2 groups, and between at 4 weeks and at 8 weeks in the experimental group (P lt; 0.05). The expression of BNIP3 of nucleus pulposus was negative in the control group; however, in the experimental group, the positive expression rates of BNIP3 of nucleus pulposus (the gray values) were 13.45% ± 1.16% and 32.00% ± 1.82% (194.32 ± 4.65 and 117.54 ± 2.11) at 4 and 8 weeks respectively, showing significant differences (P lt; 0.05). Conclusion The decrease of cell density in nucleus pulposus is involved in the development of intervertebral disc degeneration. Cell apoptosis is one of reasons in the decrease of nucleus pulposus cell; BNIP3 is involved in nucleus pulposus cell apoptosis in the degenerative intervertebral disc.
Objective
To observe the effect of cationic liposomal ceftazidime (CLC) combined with nano-hydroxyapatite/β-tricalcium phosphate (n-HA/β-TCP) in the treatment of chronic osteomyelitis of rabbits.
Methods
Thirty healthy New Zealand white rabbits (4-6 months old; weighing, 2-3 kg) were selected to prepare the chronic osteomyelitis models. After 4 weeks, the gross observation, X-ray examination, and bacteriological and histopathological examinations were done; the models were made successfully in 27 rabbits. Of 27 rabbits, 24 were randomly divided into 4 groups (n=6): only debridement was performed in group A; ceftazidime was given (90 mg/kg), twice a day for 8 weeks after debridement in group B; ceftazidime and n-HA/β-TC were implanted after debridement in group C; and CLC and n-HA/β-TCP were implanted after debridement in group D. Before and after treatments, X-ray examination was done, and Norden score was recorded. At 8 weeks after treatment, the specimens were harvested for gross observation and for gross bone pathological score (GBPS) using Rissing standard; half of the specimens was used for histological observation and Smeltzer scoring, the other half for bacteriological examination and calculation of the positive rate of bacteria culture.
Results
At 8 weeks after treatment, Norden score of group D was significantly lower than that of groups A, B, and C (P lt; 0.05), but no significant difference was found among groups A, B, and C (P gt; 0.05). At 8 weeks after treatment, sinus healed in groups C and D, but sinus was observed in groups A and B; the GBPS scores of groups C and D were significantly lower than those of groups A and B (P lt; 0.05). The Smeltzer scores of groups C and D were significantly lower than those of groups A and B (P lt; 0.05). The positive rates of bacteria culture of groups C (0) and D (0) were significantly lower than those of group A (25.0%) and group B (16.7%) (P lt; 0.05).
Conclusion
CLC combined with n-HA/β-TCP has good effect in treating chronic osteomyelitis of rabbits, and it has better effect in treating chronic osteomyelitis of rabbits than ceftazidime with n-HA/β-TCP.
【Abstract】 Objective To investigate both incidence and mechanism attributing to steroid-associated osteonecrosisof femoral head(ONFH) using an experimental protocol with a single low-dose l i popolysaccharide (LPS) injection andsubsequently three injections of high-dose methylprednisolone (MPS). Methods Twenty-five New Zealand white rabbits with body weight of (3.0 ± 0.3) kg were divided randomly into 2 groups. In treatment group, 19 rabbits received one intravenous injection of LPS (10 μg/kg); 24 hours later, three injections of 20 mg/kg of MPS were given intramuscularly at an interval of 24 hours. Additional 6 rabbits which received normal sal ine injection at the same time point were used as controls(control group). The blood samples were collected for hematological examinations before and after LPS injection, MRI was performed on bilateral hip six weeks after last MPS injection, meanwhile, bone marrow was aspirated from femoral head region to evaluate stem cell’s activity. Bilateral femoral heads were harvested to make histopathology examination. Results All animals survived throughout the experiment period except one death on the second day after LPS injection. In the histopathological examinationfor the femoral head, ONFH+ was observed in 16 rabbits (88.9%), and the lesions were mainly in the metaphysis. In ONFH+ rabbits, micro vessels fibrous thrombosis and extravascular marrow fat cell size increasing were found around necrotic bone; The femoral heads of control group had no changes. MRI accurate ratio was 93.8% (15/16). Compared to basel ine, a significant decrease in ratio of tissue plasminogen activator/plasminogen activator inhibitor 1 and activated partial thromboplatin time, and a significant increase in ratio of low-density l ipoprotein/high-density l ipoprotein were only found in ONFH+ rabbits (P lt; 0.05). Meanwhile there was a significant decrease in the number of CFU-F (8.50 ± 9.63) compared with the control (70.17 ± 7.78, P lt; 0.05). Conclusion A single low-dose LPS injection and subsequent three injections of high-dose MPS is effective on building steroid-associated ONFH model, coagulation and l ipometabol ism abnormal ity, activity degeneration of stem cell may be the key factors of ONFH.
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 research the effect of porcine acellular dermal matrix in the reconstruction of abdominal wall defects in rabbits, and to investigate the appl ication feasibil ity of xeno-transplantation of acellular dermal matrix. Methods The porcine acellular dermal matrix was prepared from a health white pig. Twenty-six Japanese white rabbits (weighing 2.2-2.3 kg, female or male) were randomly assigned to 2 groups: the control group (n=6) and the experimental group (n=20). In the control group, the full-thickness abdominal wall defect of 5.0 cm × 0.5 cm was made, and the defect wassutured directly; in the experimental group, the full-thickness abdominal wall defect of 5.0 cm × 2.5 cm was made, and the defect was repaired with porcine acellular dermal matrix patch at the same size as the defect. At 5 weeks after surgery, the incidence of hernia and the intra-abdominal adhesions were observed and the wound breaking strength was compared between the patchfascia interface and the fascia-fascia interface. The graft vascularization was evaluated through histological analysis at 6 months after surgery in the experimental group. Results No hernia occurred in all rabbits of 2 groups. At 5 weeks after surgery, heal ing was observed between patch and the muscularfascia; the vascularization was seen in the porcine acellular dermal matrix patch. There was no significant difference in the adhesion grade (Z= —0.798, P=0.425) between the experimental group (grade 2 in 1 rabbit, grade 1 in 5, and grade 0 in 12) and the control group (grade 1 in 1 and grade 0 in 5). No significant difference was found (t= —0.410, P=0.683) in the breaking strength between the patch-fascia interface in the experimental group [(13.0 ± 5.5) N] and the fascia-fascia interface in control group [(13.6 ± 4.0) N]. In the experimental group, the small vessels and the infiltration of inflammatory cells were observed in the porcine acellular dermal matrix patch after 5 weeks through histological observations. The junctions of the patch-fascia interface healed with fibrous connective tissue. At 6 months after surgery, the inflammation was subsided and the collagen fiber of the patch was reconstructed. Conclusion The porcine acellular dermal matrix patchhas good results in repairing full-thickness abdominal wall defect. The patch-fascia interface has siml iar breaking strength to the fascia-fascia interface. The collagen fibers of the patch are reconstructed.
ObjectiveTo establish an rabbit model of early steroid-induced avascular necrosis of the femoral head (SANFH) and evaluate its validity with MRI and pathological examination.
MethodsTwenty 6-month-old rabbits (weighing, 2-3 kg) were randomly divided into 2 groups (control group and model group), 10 rabbits in each group. Dexamethasone sodium phosphate solution (10 mg/kg) was injected into bilateral gluteus in model group, and the same amount of saline was injected in control group, every 3 days for 14 times. General observation was done after modelling. Osteonecrosis was verified by pathological observation and MRI findings at 6 weeks.
ResultsAfter 6 weeks, rabbits did not show obvious changes in control group; increased hair removal, decreased food intake, and slight limp were observed in model group. The MRI results showed normal shape of the bilateral femoral head and no abnormal signals in control group; irregular shape of the bilateral femoral head and a slice of irregular abnormal signals were observed, and necrosis and cystolization of the subchondral bone and sparse changes of trabecular bone were shown in model group. General observation from coronal section of femoral head showed smooth red cartilage surface in control group; on the contrary, the cartilage surface of the femoral head became dull, thin even visible hemorrhage under articular cartilage and necrosis of the femoral head were observed. The histopathological examination indicated that trabecular bone of the femoral head in control group was massive, thick, and close, and osteocytes in the bone lacunae had normal shapes. The osseous trabecular became thinner and broken; karyopyknosis of osteocytes and bone empty lacunae could be obviously seen in model group. The rates of empty lacunae were 8.0%±0.5% in control group and 49.0%±0.3% in model group, showing significant difference (t=21.940, P=0.000).
ConclusionEstablishing a model of early SANFH through injecting shortterm, shock, and high dose of dexamethasone, and it can been evaluated effectively with MRI and pathological examination.
Objective To investigate the outcome of repairing the peripheral nerve defects with the tissue engineered nerve constructed by Schwann cells and fibrin glue. Methods Wallerian degenerated sciatic nerve were harvested from the 4-week-old New Zealand rabbits for culture of Schwann cells. The Schwann cells were then separated, amplified and purified, and then were identified by the S-100 protein immunochemical staining. The cultured Schwann cells (1×106/ml) were mixed with fibrin glue to form the Schwann cell-fibrin glue compound, which was observed by the inverted phase contrastmicroscope. The compound filled some silicone tubes (Group A) and biomembrane (Group B) to fabricate the tissue engineered nerves with a purpose of repairing the 10-mm defects in the New Zealand rabbit tibia nerves. The autologous nerve grafting was performed in Group C. The electrophysiological examination and the histomorphological analysis were performed at 10 weeks after the transplantation. Results All the rabbits survived through the experiment. In Group A, all the rabbits developed an ulcer in the soles of their left feet at 3-4weeks after the transplantation, while less ulceration developed in Groups B and C. At 10 weeks after the transplantation, the electrophysiological examination was performed, the elective stimulation failed to pass through the nerve grafts, and no composed muscular action potential was found in all the rabbits in Group A; the elective stimulation could pass through all the nerve grafts in Groups B and C, and could evoke the composed muscular action potential; the composed muscular action potential and the nerve conduct velocity in the two groups were 4.21±0.82 mV and 3.40±5.40 m/s vs. 4.80±1.15 mV and 36.55±6.43 m/s(Pgt;0.05). In Group A, no regrown axon was found in the nerve grafts, but neuromawas found to have formed in the both ends of the silicon tube. In Groups B and C, there was no obvious neuroma formation but regrown axons could be found to have regenerated. The histomorphological analysis on the regrown axons showed thatthere was no statistically significant difference between Groups B and C. Conclusion The tissue engineered nerve fabricated with Schwann cells, fibrin glue, and biomembrane can promote the nerve regeneration, and its reparative effect is similar to that of the autologous nerves; therefore, the future of its clinical practice is brilliant.
In this experiment, two proximal ends of themedian and ulnar nerves of rabbit wereapproxirnated within the chitin tube for thepurpose to inhibit the neuroma formation. Byobservation under light and transmission electronmicrnscopo and immunohistochemistry, wefound that: (1) the axons of the two proximalstumpe could regenerate in the chitin tube for 2to 5mm, and then ceased to grow when anaxonal overlap happened resulting in inhibitingneuroma formation; (2) chitin tube could bedegradated a...
Objective
To study the effect of the human umbilical cord blood on the content of trace elements in whole blood during fracture healing in rabbits and to explore the mechanism of promoting fracture healing.
Methods
The right tibial fracture model was made in 63 white New Zealand rabbits (aged, 4-5 months; weighing, 2.0-2.5 kg). The fracture site was treated with 3 mL human umbilical cord blood (group A, n=21) and 3 mL normal saline (group B, n=21) at 3 and 8 days after operation, and was not treated as a control (group C, n=21). At 1, 2, 3, 4, 5, and 6 weeks after operation, the X-ray and histological observations were done; the contents of zinc, copper, magnesium, ferrum, calcium, and phosphorus were detected.
Results
X-ray observation showed that the fracture healing speed of group A was significantly faster than that of groups B and C; the fracture healing X-ray score of group A was significantly higher than that of groups B and C at 2-6 weeks (P lt; 0.05). The histological observation indicated that new trabeculae and osteoid of group A were significantly more than those of groups B and C; at 2-5 weeks, the histological score of group A was significantly higher than that of groups B and C (P lt; 0.05); at 6 weeks, the score of group A was significantly higher than that of group B (P lt; 0.05), but no significant difference was found between groups A and C (P gt; 0.05). Changes trend of the trace elements in 3 groups after operation was basically consistent. The content of copper first decreased and then gradually increased; the contents of ferrum, zinc, and magnesium at different time points decreased, but were basically stable; the content of calcium first increased and then decreased; the content of phosphorus first decreased and then increased. The contents of copper, zinc, magnesium, ferrum, calcium, and phosphorus in group A were significantly higher than those in groups B and C at different time points (P lt; 0.05), but there was no significant difference between groups B and C (P gt; 0.05).
Conclusion
Injection of the human umbilical cord blood at the fracture end of rabbits can significantly slow down the loss of trace elements in whole blood, ensure the contents of necessary trace elements during fracture healing, which may be one of the mechanisms of the umbilical cord blood promoting fracture healing.
Schwann cells (SC) play an important role in nerve regeneration. The cultures of both human and rabbit SC (gt;99%) were obtained, and were separately derived from the sciatic nerve of the human fetus and the rabbit respectively by "the method of reexplantation". In addition, the cryostore and resuscitation of SC were carried out, and the resuscitated cells could retain their growth properties.
