ObjectiveTo observe the effect of using tungsten drills to prepare mouse knee osteochondral injury model by comparing with the needle modeling method, in order to provide an appropriate animal modeling method for osteochondral injury research.MethodsA total of 75 two-month-old male C57BL/6 mice were randomly divided into 3 groups (n=25). Mice in groups A and B were used to prepare the right knee osteochondral injury models by using needles and tungsten drills, respectively; group C was sham-operation group. The general condition of the mice was observed after operation. The samples were taken at 1 day and 1, 2, 4, and 8 weeks after modeling, and HE staining was performed. The depth, width, and cross-sectional area of the injury site at 1 day in groups A and B were measured, and the percentage of the injury depth to the thickness of the articular cartilage (depth/thickness) was calculated. Toluidine blue staining and immunohistochemical staining for collagen type Ⅱ were performed at 8 weeks, and the International Cartilage Research Society (ICRS) score was used to evaluate the osteochondral healing in groups A and B.ResultsAll mice survived to the completion of the experiment. HE staining showed that group C had normal cartilage morphology. At 1 day after modeling, the injury in group A only broke through the cartilage layer and reached the subchondral bone without entering the bone marrow cavity; the injury in group B reached the bone marrow cavity. The depth, width, cross-sectional area, and depth/thickness of the injury in group A were significantly lower than those in group B (P<0.05). At 1, 2, 4, and 8 weeks after modeling, there was no obvious tissue filling in the injured part of group A, and no toluidine blue staining and expression of collagen type Ⅱ were observed at 8 weeks; while the injured part of group B was gradually filled with tissue, the toluidine blue staining and the expression of collagen type Ⅱ were seen at 8 weeks. At 8 weeks, the ICRS score of group A was 8.2±1.3, which was lower than that of group B (13.6±0.9), showing significant difference (t=−7.637, P=0.000).ConclusionThe tungsten drills can break through the subchondral bone layer and enter the bone marrow cavity, and the injury can heal spontaneously. Compared with the needle modeling method, it is a better method for modeling knee osteochondral injury in mice.
Objective To study the mid-facial development characteristics of the goats with cleft palate after in-utero surgical repair at different stages. Methods Twenty-four Boer hybrid female goats were selected, aged from 8 to 12 months and weighing from 35 to 55 kg. The mating day was designated for 0 day. At 30 days, pregnant was confirmed by B-ultrasound test, and the goats were divided into 5 groups (experimental groups 1, 2, 3, 4, and normal control group). Twenty pregnant goats of 4 experimental groups (n=5) were injected DL-anabasine (15 mg/day) from 31 to 42 days to establish cleft palate model of fetal lamb, 4 pregnant goats of normal control group used as controls without injection. At pregnant 65, 90, and 120 days, cleft palate was repaired in the uterus in experimental groups 1, 2, and 3, while cleft palate was not repaired in experimental group 4. After 1 month of birth, the maxillary bone width (posterior premolar morphological measurement, PPMM) and the maxillary bone length (anterior premolar morphological measurement, APMM) were measured with CT scanning. The dry skull of goats were harvested for gross observation. Results There was no significant difference in PPMM and APMM between experimental group 1 and the normal control group (P gt; 0.05), but there were significant differences between experimental groups 1 and 4 (P lt; 0.05) at 1 month after birth. Significant differences were oberved in PPMM and APMM between experimental group 2 and normal control group, experimental group 4 (P lt; 0.05). There were significant differences in PPMM between experimental group 3 and normal control group, experimental group 4 (P lt; 0.05), in APMM between experimental group 3 and normal control group (P lt; 0.05). Five goats with cleft palate in experimental group 4 died at 1-2 months after birth. Conclusion At pregnant 65 days, in-utero surgical repair of cleft palate has less influences on mid-facial development. The earlier repair is performed, the higher risk of miscarriage was.
Objective To study value of severe acute pancreatitis (SAP) rat model induced by retrograde pancreaticobiliary duct infusion of methylene blue in combination with sodium taurocholate. Methods The SPF 90 SD rats, 45 male rats and 45 female rats of them, were randomly divided into control group (C group), sodium taurocholate group (ST group) and methylene blue in combination with sodium taurocholate group (MBST group), which were retrogradely infused with the 0.9% normal saline, sodium taurocholate plus DAPI, and methylene blue plus sodium taurocholate plus DAPI respectively into the pancreaticobiliary duct. The success rate of puncture, degree necrosis of pancreas tissue, range of pancreatic lesions, and the incidence of bile or intestinal leakage were compared among the three groups. Results ① The success rate of puncture in the MBST group was significantly higher than that in the ST group (P=0.003) and the C group (P=0.006), which had no significant difference between the ST group and the C group (P=0.782). ② The necrosis degree of pancreas tissues in the MBST group and ST group became more and more severe with the extension of time (P<0.050), which in the MBST group was more serious than that in the ST group (P<0.050). ③ The point of pancreatic lesions range in the MBST group was significantly higher than that in the ST group (P=0.003). ④ The incidence of bile or intestinal leakage in the MBST group was significantly lower than that in the C group (P=0.008) and the ST group (P=0.004). Conclusions Retrograde pancreaticobiliary duct infusion of methylene blue in combination with sodium taurocholate can improve success rate of puncture, aggravate necrosis degree of pancreatic tissue, increase lesion scope of pancreatic tissue, and reduce rate of bile or intestinal leakage, which can provide a stable animal model for basic research of SAP.
ObjectiveTo explore the feasibility of establishment of a artificial joint aseptic loosening mouse model by cobalt-chromium particles stimulation.MethodsTwenty-four 8-week-old male severe combined immunodeficient (SCID) mice were divided into experimental group (n=12) and control group (n=12). The titanium nail was inserted into the tibial medullary cavity of mouse in the two groups to simulate artificial joint prosthesis replacement. And the cobalt-chromium particles were injected into the tibial medullary cavity of mouse in experimental group. The survival of the mouse was observed after operation; the position of the titanium nail and the bone mineral density of proximal femur were observed by X-ray film, CT, and Micro-CT bone scanning; and the degree of dissolution of the bone tissue around the tibia was detected by biomechanical test and histological staining.ResultsTwo mice in experimental group died, and the rest of the mice survived until the experiment was completed. Postoperative imaging examination showed that there was no obvious displacement of titanium nails in control group, and there were new callus around the titanium nails. In experimental group, there was obvious osteolysis around the titanium nails. The bone mineral density of the proximal tibia was 91.25%±0.67%, and the maximum shear force at the tibial nail-bone interface was (5.93±0.85) N in experimental group, which were significantly lower than those in control group [102.07%±1.87% and (16.76±3.09) N] (t=5.462, P=0.041; t=3.760, P=0.046). Histological observation showed that a large number of inflammatory cells could be seen around the titanium nails in experimental group, while there was no inflammatory cells, and obvious bone tissue formation was observed in control group.ConclusionThe artificial joint aseptic loosening mouse model can be successfully established by cobalt-chromium particles stimulation.
Objective To explore the feasibility of establishing a rabbit model of flail chest. Methods Flail chest model was eatablished in 12 New Zealand white rabbits after anesthesia and sterile surgery. The paradoxical movement of chest wall was recorded by the biological signal acquisition system, arterial blood was collected for blood gas analysis, the vital signs were recorded by electrocardiogram (ECG) and the lung tissue was taken for the pathological analysis at the end of the experiment. The effect of flail chest on the respiratory function of experimental animals was analyzed to evaluate the feasibility of establishing flail chest model. Results All surgeries were successful without mortality. The operation time was 41.42±7.08 min. Duration of endotracheal intubation was 79.33±12.21 min. Statistical results showed that the pH, partial pressure of arterial carbon dioxide (PaCO2) and base excess (BE) increased; while partial pressure of oxygen (PaO2) and oxygen saturation (SaO2) reduced. Pathological results showed that flail chest not intervented for a long period would lead to organic lesions. Conclusion The rabbit model of flail chest is feasible, safe, repeatable, easy and simple to handle. The animal is easy to access which is the foundation to study the disease process, recovery procedure and the efficacy after intervention.
ObjectiveTo explore the construction of heart preservation model of empty beating donor based on extracorporeal membrane oxygenation (ECMO). MethodsFrom January 2022 to August 2023, 20 Guangxi Bama miniature pigs weighing 25-30 kg were selected, half male and half female. Under general anesthesia and heparinization, a midline thoracotomy was performed. The pericardium was cut after freeing the anterior and posterior vena cavae, and a perfusion needle was inserted near the brachiocephalic artery in the ascending aorta, connected to a blood collection bag to collect 500-600 mL of blood. The anterior and posterior vena cavae were ligated, the aorta was blocked and perfused with HTK solution to stop the heart beating. The superior and inferior vena cavae were cut off, the right pulmonary vein was decompressed, the aorta and left and right pulmonary arteries and veins were cut off, and the whole heart was removed. An ECMO device was used to continuously perfuse a cardioprotective solution mainly composed of oxygenated warm blood, maintaining the isolated pig heart beating for 8 hours, monitoring (once/hour) ECMO perfusion parameters, blood gas indicators, perfusate electrolytes, detecting inflammatory factors, myocardial enzymes, myoglobin, and troponin levels. Myocardial tissue was taken for hematoxylin-eosin (HE) staining to observe myocardial cell damage and evaluate the quality of heart preservation. ResultsAmong the 20 isolated beating preservation pig hearts, 17 successfully resumed beating, 3 experienced ventricular fibrillation, resuscitated after intracardiac electrical defibrillation, and all 20 pig hearts successfully beat for 8 hours. There was no statistical difference in ECMO perfusion parameters, blood gas indicators, perfusate electrolytes, and inflammatory factors at each time point (P>0.05). There were statistical increases in myocardial enzymes, myoglobin, and troponin levels (P<0.05). HE staining results suggested that there was no severe myocardial damage. ConclusionECMO technology can be used for pig heart preservation with good results, and this study provides experimental evidence for improving heart preservation research in clinical heart transplantation.
ObjectiveTo investigate the safety and feasibility of domestic MP1000 robotic surgical system assisted thyroidectomy via submaxillary approach in porcine animal model. MethodThe thyroidectomy process assisted by the MP1000 robotic surgical system via submaxillary approach for a Bama pig in the 960th Hospital of the Joint Logistics Support Force was retrospectively analyzed. ResultsThe operation was performed as planned programme using the MP1000 robotic surgical system without opening, adding or lengthening the surgical incision. There was no mechanical problems during the MP1000 robotic surgical operation. The operative time was 53 min and the estimated intraoperative blood loss was 10 mL. There was no shaking of instruments and robotic arm during the operation, and the 3 surgical instruments cooperated skillfully, the establishment of surgical operation space successfully was completed, the thyroid blood vessels accurately and finely was dissected, and the separation, coagulation and cutting of blood vessels were smoothly completed. The recurrent laryngeal nerve and parathyroid gland were delicately dissected and protected. The carotid sheath, trachea, esophagus, and other important organs around the thyroid did not be damaged. The master-slave mapping frequency was high, and there was no delay sense during the operation. The lens resolution of MP1000 was 1 920×1 080, the surgical field of vision was clear, no visual field was defected and the visual field was stable and not shaking, light source front and intelligent adaptive temperature control system reduced the fogging of the lens, and the lens was scoured for 4 times during the operation. ConclusionAccording to the preliminary results of the experimental animal in this study, MP1000 robotic surgical system can successfully complete thyroidectomy via submaxillary approach in porcine animal model.
Objective To summarize the research progress on rodent models of cervical spinal cord injury (SCI). Methods The relevant domestic and foreign literature in recent years was reviewed, the methods of establishing the rodent models of cervical SCI and the evaluation methods of behavior, imaging, neuroelectrophysiology, and histology were summarized. Results Cervical SCI involves primary and secondary injuries. Primary cervical SCI can be simulated with contusion, contusion compression, fracture dislocation, spinal cord traction, and spinal cord transection; scondary cervical SCI can be simulated with photochemical model and excitotoxicity model. Certain evaluation methods such as behavior, imaging, neuroelectrophysiology, and histology are used to evaluation during model building and research. Conclusion Different rodent models of cervical SCI have different advantages and application directions, and it is critical importance for the study of cervical SCI to establish effective animal models.
ObjectiveTo research the procedure for creating an animal model of mitral regurgitation by implanting a device through the apical artificial chordae tendineae, and to assess the stability and dependability of the device. MethodsTwelve large white swines were employed in the experiments. Through a tiny hole in the apex of the heart, the artificial chordae tendineae of the mitral valve was inserted under the guidance of transcardiac ultrasonography. Before, immediately after, and one and three months after surgery, cardiac ultrasonography signs were noted. Results All models were successfully established. During the operation and the follow-up, no swines died. Immediately after surgery, the mitral valve experienced moderate regurgitation. Compared with preoperation, there was a variable increase in the amount of regurgitation and the values of heart diameters at a 3-month follow-up (P<0.05). ConclusionIn off-pump, the technique of pulling the mitral valve leaflets with chordae tendineae implanted transapically under ultrasound guidance can stably and consistently create an animal model of mitral regurgitation.
ObjectiveTo explore the method and feasibility of establishing patent ductus arteriosus (PDA) model in Bama miniature pig by using autologous jugular vein, and to provide a large animal model for the development of PDA occluder and the study of pulmonary hypertension associated with congenital heart disease. MethodsFive male Bama miniature pigs weighing about 45 kg were selected to gain the PDA model of the autogenous jugular vein, which was fixed by glutaraldehyde and anastomosed between the ascending aorta and the main pulmonary artery. The patency of PDA was confirmed by echocardiography and angiocardiography immediately and one week after the operation. Two animals were selected to undergo transcatheter closure of PDA via femoral vein 1 week after the operation, and the rest were euthanized to obtain PDA and lung tissue for pathological examination. ResultsThe PDA model was successfully established in all five animals with a success rate of 100.0%. Immediately and 1 week after the operation, echocardiography and angiography showed that PDA blood flow was unobstructed, and hematoxylin-eosin staining showed that PDA endothelialization was good. One week after the operation, two animals were successfully treated with transcatheter femoral vein occlusion. The pathological examination of lung tissue showed thickening of the intima and muscular layer of pulmonary arterioles, thickening of pulmonary interstitium and infiltration of neutrophils. ConclusionIt is safe and feasible to establish a large animal model of PDA by using autogenous jugular vein anastomosis between the ascending aorta and the main pulmonary artery. The model can be used for the development of PDA interventional occlusive devices and the pathophysiological study of congenital heart disease-related pulmonary hypertension.