ObjectiveTo understand the initiation, maturing, and resolution of thrombus by comparing the length and weight of thrombus at different time in the rat inferior vena cava (IVC) stenosis model. MethodsForty-eight female Sprague Dawley rats, weighing 180-230 g, were selected to prepare the IVC stenosis model by blocking the most of the IVC blood flow. The length and weight of IVC thrombus were measured at different time points, the histological features were observed via HE staining. ResultsBlood clots formed after 2 hours of modeling, the thrombus length and weight showed no significant difference between at 2 hours and 4 hours after modeling (P>0.05). The thrombus length and weight increased significantly at 6 hours, showing significant differences between at 2 and 4 hours and at 6, 8, 12, 24, and 48 hours (P<0.05); and from 6 to 48 hours, there was no significant difference in the thrombus length and weight (P>0.05), indicating that thrombus was stable, or maturing. Blood clots began to become smaller after 3 days when compared with ones at 48 hours (P<0.05), indicating the start of resolution at 3 days. At 7 days, the thrombus length and weight became further smaller when compared with ones at 3 days (P<0.05). The thrombus completely subsided at 21 days, the IVC recanalized. HE staining showed that thrombus formed after 2 hours of modeling; from 6 to 48 hours, the lumen became hyperemia, and the inflammatory cells, especially neutrophils, could be found. The organization of thrombus could be observed at 3 days and 7 days; thrombus gradually vanished at 21 days. ConclusionThe time of thrombus initiation, maturing stage, and resolution stage is 6 hours, 6 to 48 hours, and 3 to 21 days after modeling, respectively.
Abstract: Objective To study the pathophysiological mechanism of the morphological change of immature pulmonary vessels in the piglet model of congenital heart defect with decreased pulmonary blood flow established with balloon atrial septostomy and pulmonary artery banding. Methods Twenty piglets at an age of one to two months were divided into three groups with random number table. For the control group (group C,n=6), small incisions were carried out on the right chest to produce a transient reduction in the pulmonary blood; for the lowmedium pulmonary artery stenosis group (group T1, n=7), the balloon dilator was delivered through the surface of the right atrium and septostomy and pulmonary artery banding were performed, and the systolic transpulmonary artery banding pressure (Trans-PABP) was controlled to be 20.30 mm Hg; For the severe pulmonary artery stenosis group (group T2, n=7), the same surgical procedures with group T1 were performed while TransPABP was controlled to be more [CM(159mm]than 3050 mm Hg.At 2 months after surgery respectively,a lung tissue of 1.0 cm×0.8 cm×0.8 cm from the lateral segment of the right middle lobe was taken out to be observed under optic microscope. The morphological change of the distal arterioles was detected. Furthermore, the content of vascular endothelial growth factor (VEGF) and matrix metalloproteinase2( MMP2) were also examined by the method of enzymelinked immunosorbent assay (ELISA). Results The model was successfully established in all the survival piglets of the group T1 and group T2. Two months after operation, the inner diameter of the pulmonary arterioles in group T1 was significantly higher than that in group C (82.89±10.72 μm vs.74.12±9.28 μm;t=－5.892, Plt;0.05), so as group T2 (85.47±5.25 μm vs.74.12±9.28 μm;t=-6.325, Plt;0.05); the number of arterioles per square centimeter (NAPSC) of group T1 was significantly lower than that of the group C (229.70±88.00 entries/cm 2 vs. 431.50±40.60 entries/cm2; t=39.526, Plt;0.05), so as group T2 (210.00±40.30 entries/cm2 vs. 431.50±40.60 entries/cm2; t=67.858, Plt;0.05). Two months after operation, the lung expression of MMP -2 and VEGF in group T1 was significantly lower than that in group C (58.30±19.60 ng/ml vs. 81.20±16.70 ng/ml, t=14.261, Plt;0.05; 17.80±3.00 pg/ml vs. 21.40±3.80 pg/ml, t=8.482, P＜0.05), so does group T2 (42.10±15.20 ng/ml vs. 81.20±16.70 ng/ml, t=27.318, P＜0.05; 12.30±3.20 pg/ml vs. 21.40±3.80 pg/ml, t=15.139, P＜0.05). Conclusion Structural remodeling of pulmonary extracellular matrix is an important feature of the piglet model of congenital heart defect with decreased pulmonary blood flow. The arterioles show significant hypoplasia or degradation. Change in the structural proteins and cytokines during the reduction of blood in the lung is the key to structural remodeling.
Objective To explore the key technique of allogeneic whole pancreaticoduodenal transplantation (WPDT) in rats. MethodsWPDT model was established between Lewis rats as donors and Wistar rats (with type 1 diabetes mellitus) as recipients. End to side anastomosis was performed in abdominal aorta of donors and recipients. The portal vein of the graft was anastomosed with the recipients left renal vein by cuff technique. And side to side anastomosis was made between the graft duodenum and the host jejunum. ResultsForty-four of 50 rats were successfully performed WPDT. Amongthem, 8 rats died in postoperative 3 days, the survival time of residual 36 rats was 6-16 days, with an average of (10.45±3.30) days. The peak of death appeared on day 7-10 after operation. The typical acute rejection in pathological changes were observed on day 7. ConclusionSkilled microsurgical techniques and emphasis on details are important to establish WPDT model.
Objective To build animal models of keloid by method of tissue engineering and to discuss the feasibility of using it in clinical and lab researches. Methods Fibroblasts(FB) were isolated from keloids and cultured. The seventh and eighth generation of the cultured FBs were inoculated into the copolymers of polylactic acid and polyglycolic PLGA. After being cultured in rotatory cell culture system （RCCS）for 1 week,the FB was transplanted into athymic mice. The specimens were obtained 4 weeks and 8 weeks and examined histologically. Results All mice survived.The collagen patterns of all keloids were pressed in every specimen obtained 8 weeks. Fibrocytes andFB were observed in specimens by electronic microscope. There were abundent rough endoplasmic reticulum (RER) in FB， which indicated that FB’s capability of synthesizing and secreting collagen was preserved and the cellular characteristicwas remained. Conclusion There is a good affinity between PLGAand FB. The composition of PLGA and FB can form keloids in athymic mice,so that it deserves further researching and developing.
Objective To establ ish the modified model of cervical heterotopic cardiac transplantation in rats for investigation of cardiac chronic rejection. Methods Forty healthy male Wistar rats, aged 10 weeks, weighing 250-300 g, were appl ied as the donor group, and forty healthy male SD rats, aged 10 weeks, weighing 300-350 g, served as the recipient group. The donors’ pulmonary artery was anastomosed to the reci pients’ right external jugular vein by non-suture cuff technique while the donors’ innominate artery was anastomosed to the recipients’ right common carotid artery by suture microvascular anastomosis. All recipients received cyclosporin to prevent acute allograft rejection. Results Forty consecutive successful transplantations were performed. Neither anastomosis leakage nor vessel obstruction occurred. The total operation time was 40-50 minutes. The time of cuff vascular anastomosis was 2-3 minutes and that of microvascular anastomosis was 9-12 minutes. All recipients survived for more than 30 days and all allografts were examined at 30 days after the transplantation. Pathological manifestations of allograft vessels were chronic rejection. Conclusion This modified model of cervical heterotopic cardiac transplantation is simple, practical and highly reproducible and is appl icable for investigation of chronic rejection in various organ transplantation studies.
ObjectiveTo observe the pathological changes in heart and lung tissues in rats with pulmonary hypertension induced by monocrotaline. MethodsTwenty-four male Sprague-Dawley rats were randomly and equally divided into an experimental group and a control group. The rats in the experimental group were intraperitoneally injected with monocrotaline to induce pulmonary hypertension, and the rats in the control group were treated with saline. All rats were fed for 3 weeks, and the general situation were observed. Then the rats were sacrificed for measurement of mean pulmonary artery pressure (mPAP), right ventricular hypertrophy index [RV/(LV+S)], changes of myocardial cells and lung vascular, calculated density of middle membrane smooth muscle cells (SMC) in medium/small pulmonary arteries accompanied with bronchi and alveoli, media thickness of pulmonary artery (PAMT), the percentage of wall thickness with outer diameter (WT%), the percentage of wall area with total area (WA%), the average diameter of myocardial cells (AD), and myocardial nuclei density (MND). ResultsCompared with the control group, the condition of rats in the experimental group were getting worse obviously.mPAP and RV/(LV+S) were both increased (both P < 0.05). The observation by light microscope revealed that obvious myocardial hypertrophy and structure disturbances, severe luminal stenosis of medium/small pulmonary arteries, medial thickening, infiltration of inflammatory cell in tissue space, proliferation of unorganized collagen fibers in the experimental group. The observation by electronic microscope showed proliferation of endothelial cell with irregular nuclei, increased organelles and vacuoles in the experimental group. The differences in SMC, PAMT, WT%, WA%, AD, and MND were significant between two groups (all P < 0.05). ConclusionsThe monocrotaline can induced pulmonary hypertension and right ventricular hypertrophy. The mechanism may be related to severe stenosis or occlusion of the vessel lumen caused by plexiform proliferation of endothelial cells, proliferation of smooth muscle cells and collagen fibers, compensatory hypertrophy and hyperplasia of myocardial cells.
ObjectiveTo summarize the current researches and progress on experimental animal models of avascular necrosis of the femoral head. MethodsDomestic and international literature concerning experimental animal models of avascular necrosis of the femoral head was reviewed and analyzed. ResultsThe methods to prepare the experimental animal models of avascular necrosis of the femoral head can be mainly concluded as traumatic methods (including surgical, physical, and chemical insult), and non-traumatic methods (including steroid, lipopolysaccharide, steroid combined with lipopolysaccharide, steroid combined with horse serum, etc). Each method has both merits and demerits, yet no ideal methods have been developed. ConclusionThere are many methods to prepare the experimental animal models of avascular necrosis of the femoral head, but proper model should be selected based on the aim of research. The establishment of ideal experimental animal models needs further research in future.
ObjectiveTo evaluate the dynamic changes of blood flow and blood pressure of acute hindlimb ischemia of rats by laser Doppler flowmetry (LDF) and laser Doppler perfusion imaging (LDPI). MethodsThe acute hindlimb ischemia model of rats was established by resection of rats femoral arteries of left hindlimb. The blood flow and blood pressure between operated and nonoperated hindlimbs were examined by LDF on 2, 7, 14, 28, and 49 d after operation. And the blood flow was evaluated by LDPI on 7 d after operation. ResultsAll rats survived after operation and no hindlimb necrosis occurred. The mean score was 2 on 14 d after operation and 1 on 49 d after operation. The ratio of blood flow between operated and nonoperated hindlimbs on 2 d after operation significantly increased from 1 to 1.31±0.439 (P=0.021). The ratio of blood flow on 7 d (0.82±0.538) and 14 d (0.93±0.294) after operation was significantly lower than that on 2 d after operation (P=0.032 and P=0.019), although the difference between the two former was not significant (P=0.502). Furthermore, the ratio of blood flow on 28 d after operation reached the bottom (0.41±1.970), which was obviously lower than that on 2, 7, and 14 d after operation (P=0.004, P=0.007, and P=0.006). The blood flow of operated hindlimbs recovered approximately the value before operation (0.98±0.093), which was significantly lower than that on 2 d (P=0.010), higher than that on 28 d (P=0.005), but not different from that on 7 d and 14 d after operation (P=0.126 and P=0.382). The ratio of blood pressure between operated and nonoperated hindlimbs on 2 d after operation significantly increased from 1 to 0.47±0.375 (P=0.031). The ratio of blood pressure decreased on 7 d after operation (0.44±0.118), which was not different from that on 2 d after operation (P=0.203). Furthermore, the ratio of blood pressure on 14 d after operation reached the bottom (0.35±0.115), which was obviously lower than that on 2 d and 7 d after operation (P=0.001 and P=0.036). On 28 d after operation, the ratio of blood pressure increased (0.54±0.146), which was significantly higher than that on 14 d after operation (P=0.008), while not different from that on 2 d (P=0.493) and 7 d after operation (P=0.551). The ratio of blood pressure recovered approximately the value before operation (0.97±0.094), which was significantly higher than that on 2, 7, 14, and 28 d (P=0.013, P=0.021, P=0.002, and P=0.031). ConclusionAcute hindlimb ischemia model of rats can be established by resection of rats femoral arteries of left hindlimb and the most serious stage of hindlimb ischemia is on 14-28 d after operation. LDF and LDPI are of importance for monitoring the dynamic changes of rats hindlimb ischemia after operation.
Objective To make a mouse model of traumatic spinal cord injury (SCI) by Allen’s weight dropping (WD),which might be helpful for further research on the mechanism of SCI. Methods A total of 180 healthy female mice, weighing 17 - 23 g (20 g on average), were randomized into 4 groups (n=45 per group): the experimental groups of A, B and C and the control group of D. Experimental groups were distinguished by the amount of weight or the height from which the weight was dropped onto an impounder resting on the dura (2.0 × 2.5 g·cm, 2.5 × 3.0 g·cm, 3.0 × 5.0 g·cm). In group D, neural scute was opened only and spinal cord was exposed without SCI. The recovery of the lower extremity was observed at various time points (0,6 and 12 hours, 1 and 3 days, 1, 2, 4 and 8 weeks) by using the Basso mouse scale (BMS) scoring system, motor evoked potentials (MEP) and histological observation. Results MEP displayed that the incubation period of N1 wave was extended in group B after 6 hours and in group C after 12 hours. As time passed by, the incubation periods of N1 wave in group A, group B and group C began to shorten. The incubation period in group A was close to normal at 4 weeks (2.40 ± 0.12) ms, and there was no significant difference compared with group D (P gt; 0.05). The incubation period in group B was close to normal at 8 weeks (2.96 ± 0.15) ms, and there was no significant difference compared with group D (P gt; 0.05). The incubation period in group C was still relatively high at 8 weeks (3.76 ± 0.13) ms, and there was a significant difference compared with group D (P﹤0.05). Both hind l imbs of all mice were paralytic instantly after SCI, the score of main BMS was 0 point; the score of main BMS was close to 0 at the first 3 days after SCI, the score of main BMS of group A was 8.00 ± 0.13 and group B was 7.50 ± 0.31 at 8 weeks;the score of main BMS of group A was 5.45 ± 0.12 at 1 week and group B was 5.45 ± 0.15 at 2 weeks which were significant difference compared with group D (P﹤0.05).There were significant differences among groups A, B and C after 1 week of SCI (P lt; 0.05), and group C was lower than the others(P﹤0.01). The score of adjuvant BMS of group A was 10.12 ± 0.76 at 2 weeks and group B was 9.85 ± 0.55 at 8 weeks which was no significant difference compared with the group D at the same time (P gt; 0.05). Histological observation showed hemorrhage, cellular edema, inflammatory cell infiltration, nerve cell swell and solution of Nissl body 12 hours after SCI in group C. As time passed by, the number of nerve cells decreased, the gl ial cell prol iferated and Nissl body vanished. There was much gl ial cell prol iferation and cavitation 2 weeks after SCI in group C. The nerve cell decrease and cavitation in group B was sl ighter than that in group C, and group A was the sl ightest. In group D, there was no obvious change of the number of cells during the observation apart from sl ight edema in early period. Conclusion The mouse model precisely reflects the pathological and physiological features and law of change after different degrees of SCI, and can be used as a standard of mouse model of traumatic SCI by Allen’s WD.
【Abstract】Objective To establish and assess the rat model of postoperative fatigue syndrome (POFS). Methods The rat model of POFS was developed by the partial resection of the liver. The behavioral changes prior and post to operation, the disorder of nutritive intake after operation, stress reaction (pathological changes of mucous membrane in small intestine) and the hepatic albumin gene expression were observed. Results Low body temperature, lower sensitivity and reactivity were found. The serum levels of the iron, total protein, albumin, globulin and so on as the indexes of nutrition obviously dropped. The injury of the mucous membrane resulted from the stress reaction after the resection of the liver. The gene expression of the albumin decreased in the model group.Conclusion The experimental rat model of POFS by partial resection of the liver can be used for the investigation of POFS.