To investigate the protective effect of propofol on ischemia/reperfusion induced spinal cord injury in rabbits and its influence on excitatory amino acid (EAA). Methods Sixty New Zealand white rabbits weighing 2.0-2.5 kg, half males and half females, were selected. The infrarenal circumaortic clamping model was used. And 6 mL/kg different fluids were continuously infused through a catheter into the aorta distal to the clamping site at a speed of 12 mL/(kg•h) during the 30 minutes ischemia period. According to the different infusing l iquids, the rabbits were randomized into 6 groups(n=10 per group): group A, normal sal ine; group B, 10% intral ipid; group C, propofol 30 mg/kg; group D, propofol 40 mg/kg; group E, propofol 50 mg/kg; group F, propofol 60 mg/kg. At 0, 6, 24, and 48 hours after reperfusion, neurologic outcomes were scored on a Tarlov scale system. At 48 hours after reperfusion, the number of normal neurons in the anterior spinal cord was counted, and concentration of EAA in the lumbar spinal cord was measured by high performance l iquid chromatography. Results The neuroethological score was better in groups C, D, E and F than that of groups A and B (P lt; 0.05), the score of group E was the highest (P lt; 0.05), and there was no significant difference between group A and group B (P gt; 0.05). The number of normal neurons in the anterior spinal cord of groups C, D, E and F was greater than that of groups A and B (P lt; 0.05), and group E was greater than groups C, D and F (P lt; 0.05). The concentration of EAA in groups A, B, C, D, E and F was greater than that of normal tissue, the group E was the lowest (P lt; 0.05), the groups A and B were the highest (P lt; 0.05), and there was no significant difference between group A and group B (P gt; 0.05). Concentrations of glutamate and aspartic acid were negatively correlated to normal neuron numbers in the anterior spinal cord and neuroethological scores 48 hours after reperfusion, and the corresponding correlation coefficient was — 0.613, — 0.536, — 0.874 and — 0.813, respectively (P lt; 0.01). Conclusion Propofol can significantly inhibit the accumulation of EAA in spinal cord and provide a protective effect against the ischemia/reperfusion injury induced spinal cord in rabbits.
Objective To compare the difference of preparing the acellular larynx scaffold between perfusion method and immersion method, and find better way to make acellular larynx scaffold for tissue engineering. Methods Twenty 6-month-old male New Zealand rabbits, weighing 2.0-2.5 kg, were divided into perfusion group (n=10) and immersion group (n=10) at random. All the larynxes were excised in a sterile fashion. The acellular larynx scaffold was obtained by perfusionmethod and immersion method respectively, and then comparative examinations were performed by the macroscopicview, histological view, scanning electron microscope (SEM), cartilage vital ity assay and toluidine blue staining. ResultsMacroscopic view showed that the larynxes perfused by sodium dodecyl sulphate (SDS) became transparent after 2 hoursof perfusion, but the larynxes immersed by SDS over 16 hours still appeared pink-white. Histology and SEM indicated thatcompared with immersion group, perfusion group showed better acellular effect, more ventages and collagen fibers wereretained, no intact cell or nuclei remained in acellular matrix and chondrocytes were still survival. The porosity was 85.39% ± 3.16% in perfusion group and 34.72% ± 4.51% in immersion group, showing significant difference (P lt; 0.01). The chondrocyte vital ity rate of perfusion group (86.93% ± 1.52%) was higher than that of immersion group (77.73% ± 1.66%), showing significant difference (P lt; 0.01). Toluidine blue staining showed that the chondrocyte heterochromaty was ber in perfusion group than that in immersion group. Conclusion Compared with immersion method, perfusion method is a better way to construct acellular larynx scaffold because it can achieve better acellular effect and retain chondrocyte vital ity at the greatest extent in the acellular larynx scaffold.
Objective To develop an experimental model of abdominal aorta transplantation with nano-biomimetictissue engineered blood vessel (NBTEBV) and to investige the change of histomorphology in evolutionary process of degradation and remodel ing. Methods Twenty 6-month-old New Zealand rabbits were included, weighing 2-3 kg, male or female. The autologous seed cells of rabbits were harvested to build NBTEBV in vitro. After the branch of abdominal aorta under kidney was l igated, about 10 mm abdominal aorta was cut and replaced by NBTEBV; the anastomotic stoma was marked by Ti cl ips. NBTEBV’s evolutionary processes of degradation and rebuilding were observed. Twelve weeks after operation, DSA and color Doppler examinations were made. At 1, 4 and 12 weeks after operation, the gross and histological observations were made and 14C binding in PLGA was detected with X-ray photon spectroscopy. Results Of 20 rabbits, 17 showed that the NBTEBV was patency; 3 died from NBTEBV occlusion 36 or 72 hours after operation. The results of DAS and color Doppler showed the blood flow was patency, the blood flow rate was normal and there was no angiectasis. The lumen of transplanted blood vessel was covered with monolayer endothel ial cells. At 1 week, smooth muscle cells (SMCs) arranged regularly and much PLGA distributed in the EMCs. At 4 weeks, SMCs arranged in a layer, ECM was forming, mimic ECM degraded partly; PLGA decreased obviously. At 12 weeks, the SMCs arranged regularly, ECM formed, mimic ECM degraded, no PLGA was seen in the wall, the shape of graft was similar to the natural vessel. The decreasing crest value of 14C in specimen showed the degradation of PLGA. Conclusion NBTEBV has a good surgical maneuverabil ity and histocompatibil ity, its remodel ing evolutionary process fits in with tissue engineering specification. Building NBTEBV with ELSP is feasible.
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.
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.
Objective To study the feasibility of core-binding factor α1 (Cbfa1) gene modified marrow mesenchymal stem cells (MSCs) composed with porcine acellular bone extracellular matrix in repairing the radial defects. Methods Radial defects of 1.2 cm in length were created in 40 Japanese white rabbits and they were divided into four groups. In group A, MSCs isolated from homogeneous rabbits were infected with Cbfa1 recombinant adenovirus and implanted into acellular bone exteracellular matrix, and then the complexes were implanted into defects. In group B, the complexes including the MSCs without Cbfa1 gene-modified and scaffoldmaterial were implanted into defects. In group C, only the scaffold material was implanted. In group D, defects were not treated as the control. The macroscopic, X-ray and histologic analysis were performed to evaluate the repair effect at 4, 8 and 12 weeks postoperatively. The repaired radius were examined by biomechanical test at 12 weeks postoperatively. Results By gross examination，mature hard new bone formed at grafted areas at 12 weeks postoperativelyin group A, osteotomized ends connected by much callus in group B and less callus in group C at grafted areas. In contrast, bone nonunion formed in group D. X-ray and histological examination showed that the repaired results of defects in the group A were better than those in others groups evidently in extracellular matrix degradation, new bone remodeling and marrow cavity rebuilding at 4 and 8 weeks postoperatively. At 12 weeks postoperatively, the cortical bone became mature lamellar bone, new bone remolding was complete and marrow cavity was smooth in group A. Only proximal end of defects showed that marrow cavity was remolded partially in group B. The continuous callus could be observed in bone defect, and no obvious marrow cavity remolding was observed in group C. Lots of fibrous connective tissue filled in defect and bone nonunion was shown in group D. There was no significant difference in the damage compress loading of repaired radius between groups A, B and D (Pgt;0.05), but there was significant difference between groups C and D(Plt;0.01).Conclusion These results demonstrate that Cbfa1 gene modified MSCs combined with acellular bone extracellular matrix can be used to repair rabbit radial defects.
Objective To investigate the in vivo degradable properties of new calcium phosphate cement (CPC) containing poly lactic-co-glycolic acid (PLGA) so as to lay a foundation for the future clinical application. Methods A novel CPC containing PLGA (CPC/PLGA) was prepared according to a ratio of 45% dicalcium phosphate anhydrous ∶ 45% partially crystallized calcium phosphates ∶ 10% PLGA. Thirty-two adult New Zealand rabbits (weighing 2.2-3.0 kg, male or female in half) were divided into the experimental group (n=17) and the control group (n=15). The bone defect models of the bilateral femoral condyles (4.5 mm in diameter and 1.5 cm in depth) were made by drilling hole. Defect at the right side was repaired with CPC/ PLGA in the experimental group and with CPC in the control group, while defect at the left side was not treated as blank control. The general condition of rabbits was observed after operation; the histological observation and bone histomorphometric analysis were performed at 2, 4, 8, 16, and 24 weeks; and scanning electronic microscope (SEM) observation was performed at 8 and 16 weeks after operation. Results All rabbits survived to the end of experiment. The histological observation showed: CPC/PLGA degraded gradually, and the new-born bone trabecula ingrew; bone trabeculae became rough and b; and CPC/PLGA almost biodegraded at 24 weeks in the experimental group. The CPC degradation was much slower in the control group than in the experimental group. The total bone tissue percentage was 44.9% ± 23.7% in the experimental group, and 25.7% ± 10.9% in the control group, showing significant difference between 2 groups (t=3.302, P=0.001); and the bone tissue percentage showed significant difference between 2 groups at 8, 16, and 24 weeks (P lt; 0.05). The results of SEM observation showed that the pore size was 100-300 μm at 8 weeks after operation, new-born bone trabecula grew into the pores and combined bly with residual cement in the experimental group. Conclusion Novel CPC/PLGA has good in vivo degradable properties, and it can be an ideal bone substitute in future clinical application.
Objective To assess the variation and its significance of messenger ribonucleic acid(mRNA) expression of endothelial nitric oxide synthase (eNOS) in allografts of common carotid transplantation model in white rabbits. Methods To establish an animal model of common carotid transplantation in vivo, 30 rabbits were divided into four groups with random number table. Group A (n=3): autografts; group B (n=9): allografts with the least treated; group C (n=9): allografts treated by penicillin/streptomycin and preserved under room temperature; group D (n=9): allografts treated by penicillin/streptomycin and cryopreserved in liquid nitrogen. All the transplanted grafts were harvested 1-3 weeks later, then compared and evaluated the histomorphological variation and eNOS mRNA expression. Results The vascular structures of autografts in group A were kept approximately normal, only a few infiltration of inflammatory cells could be found. The structural variations of allografts in other trial groups behaved similarly as, intima proliferation in the 1st week, intima hyperplasia in the 2nd week, and both intima and media hypertrophy in the 3rd week. And also there seemed that luminal thrombosis could be found in all the allografts. Allografts in group B were destructed utmost the worst in all the groups. The expression of eNOS mRNA in allografts of group B was significantly less than that in other groups (Plt;0.05). Conclusion The down-regulation of eNOS mRNA expression might lead to intima hyperplasia and thrombosis of allografts.
Objective To study the influence of ischemia-reperfusion on the expression of the hyperpolarization activated cycl icnucleotide gated cation channel 4 (HCN4) and to discuss the mechanism of functional disturbance of sinoatrial node tissue (SANT) after ischemia reperfusion injury (IRI). Methods Eighty five healthy adult rabbits, weighing 2-3 kg, were randomly divided into 3 groups: control group [a suture passed under the root section of right coronary artery (RCA) without l igation, n=5], experimental group A (occluding the root section of RCA for 30 minutes, then loosening the root 2,4, 8 and 16 hours, n=10), experimental group B (occluding the root section of RCA for 1 hour, then loosening the root 2, 4,8 and 16 hours, n=10). At the end of the reperfusion, the SANT was cut off to do histopathological, transmission electronmicroscopical and immunohistochemical examinations and semi-quantitative analysis. Results The result of HE stainingshowed that patho-injure of sinoatrial node cell (SANC) happened in experimental groups A and B after 2 hours of reperfusion, the longer the reperfusion time was, the more serious patho-injure of SANC was after 4 and 8 hours of reperfusion, SANC reached peak of damage after 8 to 16 hours of reperfusion; patho-injure of SANC was more serious in experimental group B than in experimental group A at the same reperfusion time. Immunohistochemical staining showed that the expression of HCN4 located in cellular membrane and cytoplasm in the central area of SANC and gradually decreased from the center to borderl ine. The integral absorbance values of HCN4 expression in the control group (397.40 ± 34.11) was significantly higher than those in the experimental group A (306.20 ± 35.77, 216.60 ± 18.59, 155.40 ± 19.11 and 135.00 ± 12.30) and in the experimental group B (253.70 ± 35.66, 138.70 ± 13.28, 79.10 ± 9.60 and 69.20 ± 8.42) after 2, 4, 8 and 16 hours of reperfusion (P lt; 0.05). With reperfusion time, the expression of HCN4 of SANC decreased, which was lowest after 8 hours of reperfusion; showing significant difference among 2, 4 and 8 hours after reperfusion (P lt; 0.05) and no significant difference between 8 and 16 hours after reperfusion (P gt; 0.05). At the same reperfusion time, the expression of HCN4 was higher in the experimental group A than in the experimental group B. The result of transmission electron microscope showed that ultramicrostructure of SANC was damaged after reperfusion in experimental groups A and B. The longer the reperfusion time was, the more serious ultramicrostructure damage of SANC was, and reached the peak of damage after 8 hours of reperfusion. Ultramicrostructure of SANC was not different between 8 and 16 hours of reperfusion. At the same reperfusion time, the ultramicrostructure damage of SANC was moreserious in experimental group B than in experimental group A. Conclusion IRI is harmful to the morphous and structure ofSANC, and effects the expression of HCN4 of SANC, which is concerned with functional disturbance and arrhythmia.
Objective Polylactic acid (PLA) patch has proper steric configuration, sufficient mechanic strength, and flexibil ity, to investigate the blocking effect on the intra-discal inflammation after annulus puncture sticked by medical glue so as to seal the pinhole left after annulus puncture. Methods Twenty healthy New Zealand white rabbits (weighing 2.0-2.5 kg) were randomly divided into 4 groups (n=5): groups A, B, C, and D. In group A, the rabbits underwent exposure of intervertebral disc and transverse process at L2-7 as a control; in group B, the rabbits received annulus puncture at L2-7 with an 18-gauge needle; and in groups C and D, the pinholes were sealed respectively with a PLA patch sticked with medical gel and medical gel alone after annulus puncture at L2-7. General condition of rabbits was observed after operation. The intervertebral disc tissue was harvested 1 week after operation. The tissue structure was observed by HE and Masson staining. And the expressions of inflammatory factors l ike interleukin 1β (IL-1β), tumor necrosis factor α (TNF-α), and inducible nitric oxide synthase (iNOs) were detected with immunohistochemistry and ELISA. Results All the animals survived till the end of the experiment. In group A at 1 week, the nucleus pulposus tissue had normal structure. In group B at 1 week, leak of nucleus pulposus from the pinhole and sl ight adhesion to the adjacent tissue could be seen, and the nucleus pulposus tissue had significant degenerative change by histological observation. In groups C and D, clots of coagulated medical gel and extensive adhesion to the adjacent tissue could be seen; histological observation suggested that the nucleus pulposus tissue of group C had similar histology manifestation to that of group A; while group D had similar histology manifestation to group B with obviously-decreased cells and disorder of matrix. ELISA test showed remarkably elevated expression level of inflammatory factors including IL-1β, TNF-α, and iNOs in groups B and D when compared with groups A and C, showing significant differences (P lt; 0.05), and similar expression level were observed in groups A and C, groups B and D (P gt; 0.05). Conclusion The PLA patch sticked with medical gel is effective in blocking the intra-discal inflammation 1 week after annulus puncture.