Wuzhishan Minipigs Research Articles

Novel Pedicle Navigator Based on Micro Inertial Navigation System (MINS) and Bioelectric Impedance Analysis (BIA) to Facilitate Pedicle Screw Placement in Spine Surgery: Study in a Porcine Model.

Study Design.A porcine model.Objective.The study aims to design a novel pedicle navigator based on micro-inertial navigation system (MINS) and bioelectrical impedance analysis (BIA) to assist place pedicle screw placement and validate the utility of the system in enhancing pedicle screw placement.Summary of Background Data.The incidence of pedicle screw malpositioning in complicated spinal surgery is still high.Procedures such as computed tomography image-guided navigation, and robot-assisted surgery have been used to improve the precision of pedicle screw placement, but it remains an unmet clinical need.Methods.The miniaturized integrated framework containing MINS was mounted inside the hollow handle of the pedicle finder. The inner core was complemented by a high-intensity electrode for measuring bioelectric impedance. Twelve healthy male Wuzhishan minipigs of similar age and weight were used in this experiment and randomized to the MINS-BIA or freehand (FH) group. Pedicle screw placement was determined according to the modified Gertzbein–Robbins grading system on computed tomography images. An impedance detected by probe equal to the baseline value for soft tissue was defined as cortical bone perforation.Results.A total of 216 screws were placed in 12 minipigs. There were 15 pedicle breaches in the navigator group and 31 in the FH group; the detection rates of these breaches were 14 of 15 (93.3%) and 25 of 31 (80.6%), respectively, with a statistically significant difference between groups. The mean offsets between the planned and postoperatively measured tilt angles of the screw trajectory were 4.5° ± 5.5° in the axial plane and 4.8° ± 3.3° in the sagittal plane with the navigator system and 7.0° ± 5.1° and 7.7° ± 4.7°, respectively, with the FH technique; the differences were statistically significant.Conclusion.A novel and portable navigator based on MINS and BIA could be beneficial for improving or maintaining accuracy while reducing overall radiation exposure.

The traditional Chinese medicine formula Fufang-Zhenzhu-Tiaozhi protects myocardia from injury in diabetic minipigs with coronary heart disease

Background and purposeDiabetes mellitus (DM) is a major risk factor for coronary heart disease (CHD). Previous research has reported that the Fufang-Zhenzhu-Tiaozhi (FTZ) formula has obvious effects on the treatment of dyslipidemia and hyperglycemia. In the present study, we intended to establish a convenient DM-CHD model in minipigs and investigated the protective effect of FTZ against myocardial injury and its mechanism. MethodsThe DM-CHD model was established by a high-fat/high-sucrose/high-cholesterol diet (HFSCD) combined with balloon injury in the coronary artery. Subsequently, sixteen Wuzhishan minipigs were assigned to three groups: control group, model group, and FTZ group. The model group and FTZ group were given a HFSCD, while the control group was given a normal diet (ND). FTZ was given with meals in the FTZ group. During this time, biochemical parameters, such as total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein (HDL-C), and fasting blood glucose (FBG), were measured by using testing kits. Insulin (INS) was determined by ELISA, and the homeostasis model assessment index of insulin resistance (HOMA-IR) was calculated to evaluate insulin resistance levels. After FTZ administration, the plasma levels of lactate dehydrogenase (LDH), creatine kinase isoenzyme MB (CK-MB), and cardiac troponin I (cTnI) were measured by using ELISA kits to evaluate myocardial injury. Coronary artery stenosis was analyzed by angiographic and HE staining. Myocardial ischemia was assayed with electrocardiogram (ECG). Moreover, cytokines, including interleukin-6 (IL-6), hypersensitive C-reactive protein (hs-CRP), and tumor necrosis factor-alpha (TNF-α), were measured by ELISA kits to assess inflammation. The myocardial tissue was collected, and the pathological morphology was observed by transmission electron microscopy (TEM), HE staining, and Masson staining. Western blots were used to detect the expression of PI3K, AKT, p-AKT, p-NF-κB, and NF-κB. ResultsA DM-CHD model in minipigs with glucose-lipid metabolism disorder, coronary artery incrassation and myocardial damage was successfully established through balloon injury in the coronary artery combined with HFSCD. FTZ effectively inhibited coronary artery incrassation and protected the myocardium against injury in DM-CHD minipigs. FTZ decreased proinflammatory cytokine levels and upregulated the protein expression of the PI3K/Akt pathway in the myocardium. ConclusionsA novel DM-CHD model in minipigs was successfully established through balloon injury in the coronary artery combined with HFSCD. FTZ has a protective effect against myocardial injury in DM-CHD by inhibiting inflammation and activating the PI3K/AKT signaling pathway.

An animal model study on the gene expression profile of meniscal degeneration

Meniscal degeneration is a very common condition in elderly individuals, but the underlying mechanisms of its occurrence are not completely clear. This study examines the molecular mechanisms of meniscal degeneration. The anterior cruciate ligament (ACL) and lateral collateral ligament (LCL) of the right rear limbs of seven Wuzhishan mini-pigs were resected (meniscal degeneration group), and the left rear legs were sham-operated (control group). After 6 months, samples were taken for gene chip analysis, including differentially expressed gene (DEG) analysis, gene ontology (GO) analysis, clustering analysis, and pathway analysis. The selected 12 DEGs were validated by real time reverse transcription-polymerase chain reaction (RT-PCR). The two groups showed specific and highly clustered DEGs. A total of 893 DEGs were found, in which 537 are upregulated, and 356 are downregulated. The GO analysis showed that the significantly affected biological processes include nitric oxide metabolic process, male sex differentiation, and mesenchymal morphogenesis, the significantly affected cellular components include the endoplasmic reticulum membrane, and the significantly affected molecular functions include transition metal ion binding and iron ion binding. The pathway analysis showed that the significantly affected pathways include type II diabetes mellitus, inflammatory mediator regulation of TRP channels, and AMPK signaling pathway. The results of RT-PCR indicate that the microarray data accurately reflects the gene expression patterns. These findings indicate that several molecular mechanisms are involved in the development of meniscal degeneration, thus improving our understanding of meniscal degeneration and provide molecular therapeutic targets in the future.

The Peripherin Gene Regulates the Migration of Bone Marrow Mesenchymal Stem Cells in Wuzhishan Mini Pigs.

Increasing the migratory capacity of the implanted mesenchymal stem cells (MSCs) is a major challenge in developing successful cell transplantation therapies. Nevertheless, the regulatory factors involved in the migration of BMMSCs remain largely unknown. In this study, we studied the role of the peripherin (PRPH) gene in regulating the ability of Wuzhishan mini pig (WZSP) BMMSCs to migrate in vitro. Four different shRNA vectors directed against PRPH were designed and transfected into BMMSCs. The vector with the best interference effect was chosen to be used in the following experiments. The expression level of PRPH in BMMSCs was determined by quantitative real-time PCR and western blot analysis. The migration capacity of the BMMSCs was estimated using a scratch assay, a transwell in vitro migration model assay, and filamentous actin staining. The results showed that shRNA-mediated knockdown of the expression of the PRPH gene in BMMSCs reduced the ability of these cells to migrate. Overall, these results illustrate that the PRPH gene regulates the migration of BMMSCs in the WZSP.

Protective effect and mechanism of mild hypothermia on liver injury after cardiopulmonary resuscitation in pigs

Objective: To investigate the effect of mild hypothermia therapy on liver after cardiopulmonary resuscitation. Methods: Thirty-three inbred Chinese Wuzhishan (WZS) minipigs, weighted (28±2) kg, were used to establish a ventricular fibrillation model. And 30 animals survived after cardiopulmonary resuscitation reached basic life support. The surviving animals were randomly divided into two groups: mild hypothermia group (group M, n=15) and conventional treatment group (group C, n=15). All the animals were observed for 24 hours. Blood samples were extracted at baseline, 0.5, 1, 2, 4, 6, 12 and 24 h after successful resuscitation. The concentrations of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were detected at the time points. The enzyme-linked immunosorbent assay (ELISA) was used to detect the concentrations of interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-α). The data were compared between the two groups, LSD test was used when the variance was homogeneous, and Tamhane T2 test was used when the variance was uneven. Results: Eleven pigs (73.3%) in the group M and 8(53.3%) in the group C survived at 24 h after successful resuscitation, with no statistically significant difference between the two groups (χ(2)=1.229, P=0.225). After successful resuscitation, the AST, ALT increased in both group but less in M group (all P<0.05). After successful resuscitation, the concentrations of TFN-α and IL-6 in the blood increased in both groups, reached the peak at 4h, and then decreased gradually. The concentrations of TFN-α in group M were lower than those in group C at 0.5, 2, 4 and 6 h after successful resuscitation (t=0.01, 0.01, 0.87, 0.86, all P<0.05). The concentrations of IL-6 in the group M were lower than those in group C at 0.5, 1, 2 and 4 h after successful resuscitation (t=0.23, 0.78, 0.11, 0.80, all P<0.05). Conclusions: After successful resuscitation, the release of inflammatory mediators, such as TNF-α and IL-6, and cell apoptosis may involve in liver ischemia reperfusion injury. After successful resuscitation, the liver undergoes ischemia-reperfusion injury, which may be related to the release of inflammatory mediators such as TNF-α and IL-6. Mild hypothermia therapy can prevent the release of TNF-α, IL-6 to reduce the degree of liver damage after resuscitation.

BM-MSCs from Wuzhishan mini-pigs delay the progress of renal fibrosis induced by chronic kidney disease through autocrine hepatocyte growth factor in vitro

To isolate bone marrow mesenchymal stem cells (BM-MSCs) and establish the model of chronic kidney disease (CKD) of Wuzhishan (WZS) mini-pig, and to study the repairment effect of BM-MSCs on CKD-induced renal fibrosis in vitro. Methods: Density gradient method was used to isolate and culture BM-MSCs. The cells were verified by morphology, phenotype, differentiation and so on. The left partial ureteral obstruction (LPUUO) was used to establish the CKD model, which was evaluated by B-ultrasound, single-photon emission computed tomography (SPECT), HE and Masson staining. The cells were divided into 3 groups, the tissue plus BM-MSCs group, the tissue group, and the BM-MSCs group, respectively. Seven days later, the supernatants were collected to observe the changes of hepatocyte growth factor (HGF) cumulative release. HE and Masson staining was used to observe the changes of renal tissue. Results: The isolated BM-MSCs possessed the features as follow: fibroblast-like adherent growth; positive in CD29 and CD90 expression while negative in CD45 expression; osteogenic induction and alizarin red staining were positive; alcian blue staining were positive after chondrogenic induction. Twelve weeks after the operation of LPUUO, B-ultrasound showed the thin renal cortical with pelvis effusion; SPETCT showed the left kidney delayed filling and renal impairment. The accumulation of HGF in the tissue plus BM-MSCs group was significantly higher than that in the tissue alone group at the 1st, 5th, 6th, 7th day, respectively (P<0.05). HE staining showed the different degree of renal lesions between the tissue plus BM-MSCs+CKD group and the tissue alone group, which was aggravated with the time going. Masson staining showed that the cumulative optical density of blue-stained collagen fibers in tissue plus BM-MSCs group was significantly lower than that in the tissue group at the 5th to 7th day (P<0.05). Conclusion: BM-MSCs from WZS mini-pig can inhibit or delay the progress of CKD-induced renal fibrosis through autocrine HGF in vitro.

Effects of Shenfu Injection () on cerebral metabolism in a porcine model of cardiac arrest.

To investigate the effects of Shenfu Injection (, SFI) on cerebral metabolism in a porcine model of cardiac arrest (CA). Thirty Wuzhishan minipigs were randomly assigned to the control group (n=6), epinephrine group (EP group, n=12) and Sfigroup (n=12). After 8 min of untreated ventricular fifibrillation (VF), pigs in the EP group or Sfigroup were administered with either EP (0.02 mg/kg) or Sfi(1.0 mL/kg), respectively. After successful resuscitation, cerebrospinal fluid (CSF) levels of glucose, pyruvate, lactate, glutamate and glycerol were measured at 1, 6, 12 and 24 h after recover from spontaneous circulation (ROSC). In addition, neurologic defificit score (NDS) was calculated at 24 h after ROSC. Surviving pigs were killed at 24 h after ROSC, and the brain tissue was obtained for ultra-microstructure examination. Compared with the EP group, CSF glucose and pyruvate levels were higher (all P<0.01), and lactate levels were lower in the Sfigroup (P<0.01). Meanwhile, CSF glutamate and glycerol levels in the Sfigroup were lower in comparison to the EP group (all P<0.05). In addition, Sfidecreased NDS at 24 h after ROSC (P<0.01), and alleviated the histopathological damage of the brain. Sficould alleviate brain injury after CA, which may be associated with improving cerebral metabolism.

Evaluation of the biphasic calcium composite (BCC), a novel bone cement, in a minipig model of pulmonary embolism

Polymethylmethacrylate (PMMA) bone cement, which is used as a filler material in vertebroplasty, is one of the major sources of pulmonary embolism in patients who have undergone vertebroplasty. In the present study, we established and evaluated two animal models of pulmonary embolism by injecting PMMA or biphasic calcium composite (BCC) bone cement with a negative surface charge. A total of 12 adults and healthy Wuzhishan minipigs were randomly divided into two groups, the PMMA and BBC groups, which received injection of PMMA bone cement and BBC bone cement with a negative surface charge in the circulation system through the pulmonary trunk, respectively, to construct animal models of pulmonary embolism. The hemodynamics, arterial blood gas, and plasma coagulation were compared between these two groups. In addition, morphological changes of the lung were examined using three-dimensional computed tomography. The results showed that both PMMA and BCC injections induced pulmonary embolisms in minipigs. Compared to the PMMA group, the BCC group exhibited significantly lower levels of arterial pressure, pulmonary artery pressure, blood oxygen pressure, blood carbon dioxide pressure, blood bicarbonate, base excess, antithrombin III and D-dimer. In conclusion, BCC bone cement with a negative surface charge is a promising filler material for vertebroplasty.

Transgenic Wuzhishan minipigs designed to express a dominant-negative porcine growth hormone receptor display small stature and a perturbed insulin/IGF-1 pathway.

Growth hormone (GH) is an anabolic mitogen with widespread influence on cellular growth and differentiation as well as on glucose and lipid metabolism. GH binding to the growth hormone receptor (GHR) on hepatocytes prompts expression of insulin growth factor I (IGF-1) involved in nutritionally induced compensatory hyperplasia of pancreatic β-cell islets and insulin release. A prolonged hyperactivity of the IGF-1/insulin axis in the face of insulinotropic nutrition, on the other hand, can lead to collapse of the pancreatic islets and glucose intolerance. Individuals with Laron syndrome carry mutations in the GHR gene resulting in severe congenital IGF-1 deficiency and elevated GH serum levels leading to short stature as well as perturbed lipid and glucose metabolism. However, these individuals enjoy a reduced prevalence of acne, cancer and possibly diabetes. Minipigs have become important biomedical models for human conditions due to similarities in organ anatomy, physiology, and metabolism relative to humans. The purpose of this study was to generate transgenic Wuzhishan minipigs by handmade cloning with impaired systemic GHR activity and assess their growth profile and glucose metabolism. Transgenic minipigs featuring overexpression of a dominant-negative porcine GHR (GHR(dm)) presented postnatal growth retardation and proportionate dwarfism. Molecular changes included elevated GH serum levels and mild hyperglycemia. We believe that this model may prove valuable in the study of GH functions in relation to cancer, diabetes and longevity.

Establishment of a special pathogen free Chinese Wuzhishan Minipigs Colony.

To meet the increasing demands of specific pathogen free (SPF) minipigs in biomedical researches, 8 pregnant Chinese Wuzhishan minipigs (WZSP) sows with clear background were chosen to obtain SPF WZSP by hysterectomy. At 111 ± 2 days of the pregnancy, piglets were aseptically taken out from the sows and artificially suckled for 40 to 45 days in the positive isolators. Then, the piglets defined as F0 were transferred to barrier environment and fed with standard feeds. The original SPF colony was formed for breeding by selected piglets from F0 group of 6–8 months old. Biological characteristics of SPF WZSP were collected and further compared to those of conventional (CV) WZSP, including growth performance, reproductive performance, hematology and blood biochemistry, and major pathogens detection. As a result, 61 F0 piglets were obtained from 8 candidate sows, and 55 out of them survived. After strictly selection, 35 F0 piglets were used to form the original SPF colony, which produced 14 litters of SPF piglets defined as F1. Piglet survival rates, growth performance, and reproductive performance of SPF WZSP were similar to CV WZSP. Some hematology and blood biochemistry parameters showed significant differences between SPF and CV WZSP. Eighteen kinds of pathogens were identified to be free in F0 and F1 SPF colony by repeated pathogen detections. In conclusion, we established a satisfied SPF WZSP colony maintaining original characteristics, free of controlled diseases, and being proved to be a suitable laboratory animal.

Biological Characteristics of Captive Chinese Wuzhishan Minipigs (Sus scrofa).

In order to meet the demands of experimental minipigs for biomedical researches, we have aimed at cultivating grazing Chinese Wuzhishan (WZS) minipigs and trying to make them useful and affordable since the 1990s. After more than ten years of captive cultivation following sound management practices and a rigorous selection program for fertility and litter size, we established an outbred WZS minipigs colony with a core group (14 males and 30 females) and an expanding group (20 males and 40 females). In 2010–2013 periods, extensive background data of this colony were recorded and analyzed. This paper was written to provide pertinent information about outbred WZS minipigs for producers, users, and others concerned with WZS minipigs. It contains physical characteristics, growth performance, productive performance, hematology and blood biochemistry, microsatellite analysis, organ coefficients, and carcass properties. Results show that WZS minipigs have characteristics of small body size, slow growth rate, long life cycle, high reproductive rate, and maintaining original genetic diversity. All data present that outbred WZS minipigs are suitable laboratory animal and model animal.

Hypothermia-Induced Neuroprotection is Associated with Reduced Mitochondrial Membrane Permeability in a Swine Model of Cardiac Arrest

Increasing evidence has shown that mild hypothermia is neuroprotective for comatose patients resuscitated from cardiac arrest, but the mechanism of this protection is not fully understood. The aim of this study was to determine whether prolonged whole-body mild hypothermia inhibits mitochondrial membrane permeability (MMP) in the cerebral cortex after return of spontaneous circulation (ROSC). Thirty-seven inbred Chinese Wuzhishan minipigs were successfully resuscitated after 8 minutes of untreated ventricular fibrillation (VF) and underwent recovery under normothermic (NT) or prolonged whole-body mild hypothermic (HT; 33°C) conditions for 24 or 72 hours. Cerebral samples from the frontal cortex were collected at 24 and 72 hours after ROSC. Mitochondria were isolated by differential centrifugation. At 24 hours, relative to NT, HT was associated with reductions in opening of the mitochondrial permeability transition pore, release of pro-apoptotic substances from mitochondria, caspase 3 cleavage, apoptosis, and neurologic deficit scores, as well as increases in mitochondrial membrane potential and mitochondrial respiration. Together, these findings suggest that mild hypothermia inhibits ischemia-induced increases in MMP, which may provide neuroprotection against cerebral injury after cardiac arrest.

Mild hypothermia attenuates mitochondrial oxidative stress by protecting respiratory enzymes and upregulating MnSOD in a pig model of cardiac arrest.

Mild hypothermia is the only effective treatment confirmed clinically to improve neurological outcomes for comatose patients with cardiac arrest. However, the underlying mechanism is not fully elucidated. In this study, our aim was to determine the effect of mild hypothermia on mitochondrial oxidative stress in the cerebral cortex. We intravascularly induced mild hypothermia (33°C), maintained this temperature for 12 h, and actively rewarmed in the inbred Chinese Wuzhishan minipigs successfully resuscitated after 8 min of untreated ventricular fibrillation. Cerebral samples were collected at 24 and 72 h following return of spontaneous circulation (ROSC). We found that mitochondrial malondialdehyde and protein carbonyl levels were significantly increased in the cerebral cortex in normothermic pigs even at 24 h after ROSC, whereas mild hypothermia attenuated this increase. Moreover, mild hypothermia attenuated the decrease in Complex I and Complex III (i.e., major sites of reactive oxygen species production) activities of the mitochondrial respiratory chain and increased antioxidant enzyme manganese superoxide dismutase (MnSOD) activity. This increase in MnSOD activity was consistent with the upregulation of nuclear factor erythroid 2-related factor 2 (Nrf2) mRNA and protein expressions, and with the increase of Nrf2 nuclear translocation in normothermic pigs at 24 and 72 h following ROSC, whereas mild hypothermia enhanced these tendencies. Thus, our findings indicate that mild hypothermia attenuates mitochondrial oxidative stress in the cerebral cortex, which may be associated with reduced impairment of mitochondrial respiratory chain enzymes, and enhancement of MnSOD activity and expression via Nrf2 activation.

Molecular mechanisms of therapeutic hypothermia on neurological function in a swine model of cardiopulmonary resuscitation

ObjectiveTo explore the molecular mechanisms by which mild hypothermia following resuscitation improves neurological function in a porcine model of cardiac arrest. MethodsThirty-three inbred Chinese Wuzhishan (WZS) minipigs were used. After 8min of untreated ventricular fibrillation (VF), the surviving animals (n=29) were randomly divided into two groups including serum group (n=16) and molecular group (n=13). Serum group animals were used to measure porcine-specific tumour necrosis factor-alpha (TNF-α), interleukin (IL-6, IL-10), matrix metalloproteinase (MMP9), Aquaporin-4 (AQP4), tissue inhibitor to metalloproteinase-1 (TIMP1), neuron-specific enolase (NSE) and S100B at 0.5h, 6h, 12h, 24h and 72h recovery by enzyme-linked immunosorbent assay (ELISA). Molecular group animals were used to measure cerebral cortex messenger RNA (mRNA) and protein expression of nuclear factor-κB (NF-κB), MMP9 and AQP4 by real-time (RT) quantitative polymerase chain reaction (PCR) and Western blotting at 24h and 72h recovery. Animals were further divided into either normothermia or hypothermia groups. Hypothermia (33°C) was maintained for 12h using an endovascular cooling device. Swine neurologic deficit scores (NDS) were used to evaluate neurological function at 24-h and 72-h recovery. ResultsTwenty-nine of the 33 (87.9%) animals were successfully resuscitated. The hypothermia group exhibited higher survival rates at 24h (75%) and 72h (62.5%) compared to the normothermia group (37.5% and 25%, respectively). Hypothermia markedly inhibited expression of NF-κB, TNF-α, MMP9 and NSE, and promoted expression of TIMP1 (P<0.01). The mean NDS at 24-h and 72-h recovery was 112.5 and 61, respectively, in the hypothermic group, and 230 and 207.5, respectively, in the normothermia group. ConclusionBrain protection induced by hypothermia involves inhibition of inflammatory and brain edema pathways.

Inbred Chinese Wuzhishan (WZS) Minipig Model for Soybean Glycinin and β-Conglycinin Allergy

Validated murine models have been built to assess the potential allergenicity of novel proteins. Large animals, such as pigs, share more similarities to humans in physiology and immunology than murine. Among Chinese minipigs, Wuzhishan (WZS) minipigs have the highest inbreeding coefficient, more stable heredity, and less variability, which were gastrically sensitized and excitated with diets containing 4% glycinin or 4% beta-conglycinin or neither to induce anaphylactic reactions in the present study. In glycinin- and beta-conglycinin-sensitized animals, diarrhea symptoms and skin wheal and flare responses were observed. In comparison to the control, after oral excitation with glycinin or beta-conglycinin, the serum IgE was increased by 34.4 or 38.4% and the serum histamine was increased by 42.1 or 46.9%, respectively. In addition, the serum IFN-gamma were reduced by 12.4 or 30.0%, respectively. The jejunum histamine level of beta-conglycinin-sensitized animals was increased by 196.6%, while the number of mast cells in the submucosa of jejunum and ileum of the glycinin-sensitized animals declined by 48.1 and 45.0%. In conclusion, the WZS minipig allergy models induced by soybean glycinin and beta-conglycinin represent type-I hypersensitivity reactions mediated by IgE, which could potentially be useful in determining the potential allergenicity of novel proteins.

The susceptibility of three strains of Chinese minipigs to diet-induced type 2 diabetes mellitus

Researchers have extensively used animal models to study diabetes mellitus. In this study, the authors determined the susceptibility of three strains of Chinese minipigs to diet-induced type 2 diabetes mellitus. For 8 months, the researchers fed Nongda control minipigs (n=4) a normal diet and fed Bama, Wuzhishan and Nongda minipigs (n=6 per group) a high-sucrose, high-fat diet. They measured the minipigs' body weights, fasting serum glucose concentrations and insulin concentrations each month. Every 2 months, they measured serum triglyceride, cholesterol, high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) levels and carried out intravenous glucose tolerance tests (IVGTTs). The Bama and Wuzhishan minipigs were relatively susceptible to diabetes induced by the high-sucrose, high-fat diet, though susceptibility differed among individual animals in the same strain. On the other hand, Nongda minipigs were relatively resistant to diet-induced diabetes. These results provide a foundation for diabetes-related genetic analyses in minipigs with high and low susceptibility to diet-induced type 2 diabetes.

Adipose tissue extract enhances skin wound healing

The main function of adipose tissue has been considered as storage of triglycerides. Adipose tissue was considered harmful for healing extensive and deep burns because of poor circulation and easy liquefaction in wound beds, which offer an excellent culture medium for bacteria. However, these traditional concepts have been challenged with the discovery of the endocrine function of adipose tissue. To investigate the effects of adipose tissue extract on wound healing, we created four 3.0 x 2.5 cm full-thickness wounds on each side of the back of male Wu Zhi Shan minipigs (n=6), for eight wounds in each animal. The wounds were randomly divided to receive normal saline (0.5 mL; controls), adipose tissue extract (1.5 g), basic fibroblast growth factor (50 U/cm(2)), and epidermal growth factor (50 U/cm(2)). Reduction in wound area and wound volume was accelerated with adipose tissue treatment as compared with growth factor or control treatment. The thickness of the regenerated epidermis and the number of new vascular nets were markedly increased in adipose tissue-treated wounds. Biopsy of adipose tissue-treated wounds showed enhanced expression of proliferation cell nuclear antigen (PCNA) and Factor VIII-related antigen, which indicated active cell differentiation and proliferation. In vitro study in rat tissue showed adipose tissue extracts stimulating skin growth. Bacteriology results showed no significant differences in amount or type of bacteria, whatever the treatment. These results may challenge the traditional concept that adipose tissue plays a negative role in wound healing and may offer direct evidence for encouraging the retention of adipose tissue in autologous skin grafting for skin wounds.

Experimental research on establishing chronic ischemic heart failure model of minipig with intracoronary perfusion of plastic microspheres by catheterization

To establish a stable chronic ischemic heart failure (CIHF) model of minipig caused by gradual myocardial ischemia and necrosis that was achieved with repetitive microspheres perfusion in left anterior descending artery (LAD). A total of fifteen Wuzhishan minipigs original in Hainan China (8 to 11 months old with body weight of 20 to 30 kg) were used. The 4F angiographic catheter was superselectively engaged in LAD, and 1 ml of suspending plastic microspheres fluid were given repeatedly at ten-minute intervals, which include microspheres 1.0 x 10(5)/ml, until LVEDP raising and maintaining from 15 mm Hg to 18 mm Hg and TIMI flow was less than or equal to grade 2. Electrocardiography, hemodynamic parameters, CK-MB and cTnT were monitored during the procedure. LVEF was repeatedly measured with ultracardiography at 10 d, 20 d, 30 d, 40 d, 50 d, 60 d after establishing chronic ischemic heart failure model. Meanwhile, hemodynamic indices including mRAP, mRVP, mPAP, PCWP and CO (thermo-dilution method) were measured before and two months after procedure. The success rate, stability and repetition of chronic ischemic heart failure model were identified and evaluated. Finally, myocardial infarcted area was measured and myocardial pathologic examination was investigated. Eleven minipigs survived two months after procedure. There were ten minipigs accorded with the criteria (LVEDP > 18 mm Hg CO reduced by 30%) of the CIHF model and the success rate was 66.7% with a mean of 3.2 +/- 0.9 times of microspheres injections and total doses of (3.2 +/- 0.9) x 10(5) microspheres. This resulted in 38.5% reduction in LVEF, 197.8% elevation in LVEDP and 46.8% declining in CO from baseline values (P < 0.01), while mRAP, mRVP, mPAP and PCWP increased significantly as compared with those before procedure. Cross myocardium pathology showed the ratio of necrosis area to left ventricle (LV) area was 25.4% - 34.9% (mean 28.6%) and light microscopy examination of LV myocardium revealed that intravascular semitransparent plastic microspheres distributed throughout subendocardium of left ventricular anterior and apical parts, with more numerous focal myofiber necrosis, which characterized by pathologic founding of ischemic necrosis of myocardium with fibre proliferation. A stable CIHF model could be established in Chinese Wuzhishan minipigs with intra-coronary microspheres perfusion via superselectively engaging in LAD, which was prior to those of drug-induced, tachycardia-pacing induced or coronary artery ligation-induced, and had the advantages of stability, closed chest, mild trauma higher success rate and easy for repetition. It might be suitable for using the research of CIHF as large reliable experimental animal model.

Study on Pork Characteristics of Chinese Wuzhishan Mini-Pig

This research was conducted to evaluate the meat traits of Wuzhishan mini-pigs (WZSP). Young Xiang-pigs (XPs) and adult Beijing Black-pigs (BPs) were used as the control group of young and adult WZSPs respectively. Studies included evaluation of carcass properties, meat sensory character, edible quality and processing performance. The studies show the WZSP is of thin skin, low back-fat, high lean percentage and meat productivity. The results of meat quality analysis indicate the WZSP pork is of fresh meat color, good elasticity, less marbling, rich amino acid especially pre-flavor amino acid and low intra-muscular fat. Meanwhile, WZSP pork presents benign processing performance of low loose water percentage, low drip loss, and eminent bounding water capability.