In order to study the mechanical behavior of degeneration and nucleotomy of lumbar intervertebral disc, compression experiments with porcine lumbar intervertebral discs were carried out. The lumbar intervertebral discs with trypsin-treated and nucleus nucleotomy served as the experimental group and the normal discs as the control group. Considering the effects of load magnitude and loading rate, the relationship between stress and strain, instantaneous elastic modulus and creep property of intervertebral disc were obtained. The creep constitutive model was established. The results show that the strain and creep strain of the experimental group increase significantly with the increase of compression load and loading rate, whereas the instantaneous elastic modulus decreases obviously, compared with the control group. It indicates that the effect of load magnitude and loading rate on load-bearing capacity of intervertebral disc after nucleotomy is larger obviously than that of normal disc. The creep behavior of the experimental group can be still predicted by the Kelvin three-parameter solid model. The results will provide theoretical foundation for clinical treatment and postoperative rehabilitation of intervertebral disc disease.
Animals ; Biomechanical Phenomena ; Intervertebral Disc ; physiology ; surgery ; Lumbar Vertebrae ; Stress, Mechanical ; Swine ; Weight-Bearing

PURPOSE: We explored the performance of and pressure elevation caused by small-diameter microtubes used to reduce overfiltration. METHODS: Using a syringe pump-driven constant-flow setting (2 µL/min), pressures were measured for polytetrafluoroethylene (PTFE) microtubes 5 mm in length with inner diameters of 51, 64, and 76 µm and for polyether block amide (PEBAX) microtubes with an inner diameter of 76 µm. Experiments (using microtubes only) were initially performed in air, water, and enucleated pig eyes and were repeated under the same conditions using intraluminal 9/0 nylon stents. RESULTS: The pressures measured in air in 51-, 64-, and 76-µm-diameter PTFE microtubes differed significantly (22.1, 16.9, and 12.2 mmHg, respectively; p < 0.001), and that of the 76-µm-diameter PEBAX microtube was 15.8 mmHg (p < 0.001 compared to the 12.2 mmHg of the 76-µm-diameter PTFE microtube). The pressures measured in water also differed significantly among the three microtubes at 3.9, 3.0, and 1.4 mmHg, respectively, while that in the PEBAX microtube was 2.6 mmHg (all p < 0.001). Using the intraluminal stent, the pressure in water of the three different PTFE microtubes increased to 22.6, 18.0, and 4.1 mmHg, respectively, and that in the PEBAX microtube increased to 10.5 mmHg (all p < 0.001). Similar trends were evident when measurements were performed in pig eyes. CONCLUSIONS: Although microtubes of smaller diameter experienced higher pressure in air, reduction of the inner diameter to 51 µm did not adequately increase the pressure attained in water or pig eyes. Insertion of an intraluminal stent effectively elevated the latter pressures. PEBAX microtubes created higher pressures than did PTFE microtubes.
Animals ; Disease Models, Animal ; Glaucoma/physiopathology/*surgery ; *Glaucoma Drainage Implants ; Intraocular Pressure/*physiology ; Ophthalmologic Surgical Procedures/*instrumentation ; *Polytetrafluoroethylene ; Prosthesis Design ; Swine

BACKGROUNDCyanotic congenital heart defects with decreased pulmonary blood flow due to lung ischemia, hypoxia, and others lead to infant morbidity and mortality more than acyanotic heart disease does. Despite the great effort of medical research, their genetic link and underlying microRNAs molecular mechanisms remain obscure. In this study, we aimed to investigate microRNAs regulation during cyanotic defects in lung of immature piglets.

METHODSCyanotic piglet model was induced by main pulmonary artery-left atrium shunt with distal pulmonary artery banding. Four weeks later, hemodynamic parameters confirmed the development of cyanotic defects and pulmonary lobe RNA was extracted from all animals. We studied the repertoire of porcine lung microRNAs by Solexa deep sequencing technology and quantified highly expressed microRNAs by microarray hybridization. Furthermore, we quantitated selected microRNAs from cyanotic and control piglets by quantitative RT-PCR.

RESULTSAfter surgical procedure 4 weeks later, the cyanotic model produced lower arterial oxygen tension, arterial oxygen saturation, and higher arterial carbon dioxide tension, hematocrit and hemoglobin concentration than controls (all P < 0.05). In 1273 miRNAs expressed in the immature piglets lungs, 2 most abundant microRNAs (miR-370 and miR-320) demonstrated significant difference between cyanotic and control group (all P < 0.05).

CONCLUSIONOur results extended lung microRNA profile in immature piglets and suggested that miR-370 and miR-320 are significantly up-regulated in cyanotic lung tissues.

Animals ; Chronic Disease ; Cyanosis ; genetics ; physiopathology ; Gene Expression Profiling ; Heart Atria ; surgery ; MicroRNAs ; analysis ; physiology ; Pulmonary Artery ; surgery ; Pulmonary Circulation ; Real-Time Polymerase Chain Reaction ; Swine ; Swine, Miniature

Regeneration of periodontal tissue is the most promising method for restoring periodontal structures. To find a suitable bioactive three-dimensional scaffold promoting cell proliferation and differentiation is critical in periodontal tissue engineering. The objective of this study was to evaluate the biocompatibility of a novel porcine acellular dermal matrix as periodontal tissue scaffolds both in vitro and in vivo. The scaffolds in this study were purified porcine acellular dermal matrix (PADM) and hydroxyapatite-treated PADM (HA-PADM). The biodegradation patterns of the scaffolds were evaluated in vitro. The biocompatibility of the scaffolds in vivo was assessed by implanting them into the sacrospinal muscle of 20 New Zealand white rabbits. The hPDL cells were cultured with PADM or HA-PADM scaffolds for 3, 7, 14, 21 and 28 days. Cell viability assay, scanning electron microscopy (SEM), hematoxylin and eosin (H&E) staining, immunohistochemistry and confocal microscopy were used to evaluate the biocompatibility of the scaffolds. In vitro, both PADM and HA-PADM scaffolds displayed appropriate biodegradation pattern, and also, demonstrated favorable tissue compatibility without tissue necrosis, fibrosis and other abnormal response. The absorbance readings of the WST-1 assay were increased with the time course, suggesting the cell proliferation in the scaffolds. The hPDL cells attaching, spreading and morphology on the surface of the scaffold were visualized by SEM, H&E staining, immnuohistochemistry and confocal microscopy, demonstrated that hPDL cells were able to grow into the HA-PADM scaffolds and the amount of cells were growing up in the course of time. This study proved that HA-PADM scaffold had good biocompatibility in animals in vivo and appropriate biodegrading characteristics in vitro. The hPDL cells were able to proliferate and migrate into the scaffold. These observations may suggest that HA-PADM scaffold is a potential cell carrier for periodontal tissue regeneration.
Absorbable Implants ; Acellular Dermis ; Animals ; Biocompatible Materials ; chemistry ; Cell Adhesion ; physiology ; Cell Culture Techniques ; Cell Movement ; physiology ; Cell Proliferation ; Cell Shape ; physiology ; Cell Survival ; physiology ; Durapatite ; chemistry ; Fibrosis ; Humans ; Microscopy, Electron, Scanning ; Muscle, Skeletal ; surgery ; Necrosis ; Periodontal Ligament ; cytology ; surgery ; Rabbits ; Regeneration ; physiology ; Swine ; Tissue Engineering ; methods ; Tissue Scaffolds ; chemistry

BACKGROUNDMost of endovascular stent-graft modifications to preserve side branch must be customized according to extensive pre-operative assessment, which may not be possible in many hospitals and emergency settings. The study was to develop a novel stent-grafts system that would allow in situ "fenestration", with less reliance on preoperative imaging.

METHODSThe magnitude of pressure difference (PD) between left subclavian artery (LSA) and aortic arch were measured in 12 experimental pigs. Changes of PD before and after LSA was covered were analyzed respectively. The novel stent graft was made by multi-dimensional and multiple textiles forming technology. According to the PD measurement in pigs, we evaluated the feasibility of the stent-graft in a mock circulation system.

RESULTSIn pigs, the blood pressure of aortic arch was significantly higher than that of LSA after it was covered (P < 0.001) and PD was (42.78 ± 5.17) mmHg. After target vessel was covered and when PD between the LSA and aorta reached the magnitude measured in pigs, contrast media oozed from the cranny of graft to the LSA, which was generated by sliding and deformation of yarns of novel stent-graft.

CONCLUSIONSThe study proposes the design of pressure difference-induced perforation aortic stent-grafts system and verifies that the PD between LSA and aortic arch is high enough to allow in situ "fenestration" by stent graft made by multi-dimensional and multiple textiles forming technology.

Animals ; Aorta, Thoracic ; surgery ; Blood Pressure ; physiology ; Blood Vessel Prosthesis ; Blood Vessel Prosthesis Implantation ; Prosthesis Design ; Subclavian Artery ; Swine

BACKGROUNDHilar cholangiocarcinoma is a malignant tumor that is difficult to cure. The aim of this study was to observe the effects of flow-controlled partial portal vein arterializations (PPVA) on liver regeneration after hepatectomy in minipigs with chronic obstructive jaundice.

METHODSEight minipigs were made into chronic obstructive jaundice models. United semi-hepatectomy, which imitates extended radical surgery for treatment of hilar cholangiocarcinoma, was then performed. The eight minipigs were randomly divided into groups A and B (n = 4 minipigs each). PPVA was performed in Group A but not in Group B. The effects of flow-controlled PPVA on live regeneration after hepatectomy were observed for 30 days after hepatectomy.

RESULTSThe portal vein PO(2) at the immediate time point and on postoperative day 30 was higher in Group A ((47.33 ± 2.43) and (48.50 ± 4.44) mmHg) than in Group B ((35.38 ± 4.06) and (35.55 ± 2.55) mmHg respectively, all P < 0.01). The mitotic index of liver cells on postoperative days 14 and 21 was higher in Group A (12.55% ± 2.85% and 15.25% ± 1.99% respectively) than in Group B (6.85% ± 2.10% and 11.88% ± 1.15% respectively, all P < 0.05). The regeneration rate of residual liver on postoperative days 14 and 21 was higher in Group A (24.56% ± 6.15% and 70.63% ± 9.83% respectively) than in Group B (11.96% ± 5.43% and 44.92% ± 7.42% respectively, P < 0.05 and P < 0.01 respectively).

CONCLUSIONFlow-controlled PPVA can promote liver regeneration after hepatectomy and prevent liver failure in minipigs with chronic obstructive jaundice.

Acepromazine ; therapeutic use ; Animals ; Arteriovenous Shunt, Surgical ; methods ; Atropine ; therapeutic use ; Female ; Hepatectomy ; methods ; Jaundice, Obstructive ; surgery ; Ketamine ; therapeutic use ; Liver Regeneration ; physiology ; Portal Vein ; surgery ; Swine ; Swine, Miniature

Fragments of testis tissue from immature animals grow and develop spermatogenesis when grafted onto subcutaneous areas of immunodeficient mice. The same results are obtained when dissociated cells from immature testes of rodents are injected into the subcutis of nude mice. Those cells reconstitute seminiferous tubules and facilitate spermatogenesis. We compared these two methods, tissue grafting and cell-injection methods, in terms of the efficiency of spermatogenesis in the backs of three strains of immunodeficient mice, using neonatal porcine testicular tissues and cells as donor material. Nude, severe combined immunodeficient (SCID) and NOD/Shi-SCID, IL-2Rgammacnull (NOG) mice were used as recipients. At 10 months after surgery, the transplants were examined histologically. Both grafting and cell-injection methods resulted in porcine spermatogenesis on the backs of recipient mice; the percentage of spermatids present in the transplants was 67% and 22%, respectively. Using the grafting method, all three strains of mice supported the same extent of spermatogenesis. As for the cell-injection method, although SCID mice were the best host for supporting reconstitution and spermatogenesis, any difference from the other strains was not significant. As NOG mice did not show any better results, the severity of immunodeficiency seemed to be irrelevant for supporting xeno-ectopic spermatogenesis. Our results confirmed that tubular reconstitution is applicable to porcine testicular cells. This method as well as the grafting method would be useful for studying spermatogenesis in different kinds of animals.
Animals ; Cell Transplantation ; methods ; Injections ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Inbred NOD ; Mice, Nude ; Mice, SCID ; Organ Size ; Seminiferous Tubules ; cytology ; physiology ; transplantation ; Spermatids ; cytology ; transplantation ; Spermatogenesis ; physiology ; Subcutaneous Tissue ; surgery ; Swine ; Tissue Transplantation ; methods ; Transplantation, Heterologous ; methods

OBJECTIVETo investigate the local changes of biomechanics after osteotomy of mandibular outer cortex in body and angle areas.

METHODSSix minitype pigs at the age of 8 to 12 months were selected. The mandibular outer cortex that involves angle and part of body was removed in one side. The animals were killed 24 weeks after operation. Bone strut was taken from mandibular angle region bilaterally and sent for biomechanical test

RESULTSThere was no biomechanical difference between the two angle areas of experimental and normal sides 24 weeks after mandibular outer cortex osteotomy (maximum load P > 0.05, rigidity P > 0.05).

CONCLUSIONSMandibular outer cortex osteotomy had no influence on local biomechanics.

Animals ; Biomechanical Phenomena ; Female ; Male ; Mandible ; physiology ; surgery ; Osteotomy ; Postoperative Period ; Swine ; Swine, Miniature

OBJECTIVETo explore the effect of burying testis in thigh pocket on spermatogenesis.

METHODSGuizhou miniature male pigs at child-bearing period were randomly divided to receive operation of scrotum incision and dissection with the testis burying in thigh pocket (experimental group) or without (control group). 3 months later, testis biopsy was performed on 2 pigs from each group for pathological examination. Then every male pig from both experimental (n = 6) and control group (n = 6) got a mating partner and lived together for 3 months. The fertility of the male pigs was observed. 6 months after operation, testis biopsy was performed again on all the animals from both the groups.

RESULTSBoth at 3 months and 6 months after operation, the pathological examination showed the spermatogenic cells of all stage in contorted seminiferous tubules markedly decreased with no mature sperm in experimental group, while normal spermatogenic cells with mature sperm in control group. After the male pigs lived with mating partners for 3 months, no female pigs staying with the experimental group became pregnant, but the male pigs in control group had a normal fertility.

CONCLUSIONSBurying testis in thigh pocket impedes spermatogenesis in the miniature male pig. So burying testis in thigh pocket is not recommended for patients with scrotum skin defect who wish to remain fertile.

Animals ; Female ; Fertility ; Male ; Pregnancy ; Pregnancy Rate ; Scrotum ; Skin ; injuries ; Spermatogenesis ; Swine ; Swine, Miniature ; Testis ; physiology ; Thigh ; surgery

A set of system for in vitro testing and analyzing the 3D motion in the cervical spine specimen before and after the ACP's (anterior cervical plates) implantation is introduced in this paper. Six porcine specimens with C3 - C6 mounted by the custom clamp were used to mimic human physiological cervical motions. A non-contact real-time measurement system based on CCD was used to track segmental cervical motion signals during the motion. A Matlab program based on multibody dynamics was processed to give the angle changes between adjacent vertebras during the motion. The experimental results show that the methodology can appraise the clinical properties of the ACP effectively.
Animals ; Biomechanical Phenomena ; Cervical Vertebrae ; physiology ; surgery ; Range of Motion, Articular ; physiology ; Spinal Fusion ; methods ; Swine ; Treatment Outcome