Comparative study of a rabbit model of spinal tuberculosis using different concentrations of Mycobacterium tuberculosis

BACKGROUND Tuberculosis is among the most devastating infectious diseases worldwide.Spinal tuberculosis is not easy to detect at an early stage,which without effective treatment often leads to spinal deformity and spinal cord damage which in turn cause complications such as paraplegia and quadriplegia.In this study,we established a model using three concentrations of bacteria and carried out a comprehensive evaluation of the model by imaging,general observations,and histopathological and bacteriological studies.AIM To establish a rabbit model of spinal tuberculosis and examine the effect on the model’s efficacy using different concentrations of Mycobacterium tuberculosis(M.tuberculosis)inoculum.METHODS New Zealand rabbits were randomly divided into experimental,control and blank groups.The experimental and control animals were sensitized with complete Freund′s adjuvant,a hole was drilled beneath the upper endplate of the L6 vertebral body and filled with gelfoam sponge.The experimental group was divided into three subgroups(experimental 1,experimental 2,experimental 3)and infused with M.tuberculosis suspension at various concentrations.The control group was inoculated with saline and the blank group received no treatment.The 12-week post-operative survival rates were 100%,80%and 30%in the experimental groups inoculated with concentrations of 106,107 and 108 CFU/mL bacteria,respectively.RESULTS The survival rate of the control and blank groups was 100%.Vertebral body destruction at 8 weeks in the three experimental groups as determined by X-ray analysis was 33.3%,62.5%and 66.7%,and by computed tomography(CT)and 3-dimensional CT 44.4%,75%and 100%,respectively.At 12 weeks,the figures were 44.4%,75%and 100%by X-ray analysis and 44.4%,100%and 100%by CT and 3-dimensional CT,respectively.All surviving rabbits of the experimental groups had vertebral destruction.The positive bacterial culture rates were 22.2%,75%and 66.7%,respectively,in the experimental groups.After being sensitized with complete Freund's adjuvant,large differences were observed in the extent of spinal tuberculosis after inoculation of the rabbits with different concentrations of H37RV standard M.tuberculosis.CONCLUSION The experimental 1 had a low success rate at establishing an infection.The experimental 3 resulted in high mortality and complication rates.The experimental 2 was optimum for establishing a spinal tuberculosis model based on the high level of symptoms observed and the low rabbit mortality.

Genome-edited rabbits:Unleashing the potential of a promising experimental animal model across diverse diseases

Animal models are extensively used in all aspects of biomedical research,with substantial contributions to our understanding of diseases,the development of pharmaceuticals,and the exploration of gene functions.The field of genome modification in rabbits has progressed slowly.However,recent advancements,particularly in CRISPR/Cas9-related technologies,have catalyzed the successful development of various genome-edited rabbit models to mimic diverse diseases,including cardiovascular disorders,immunodeficiencies,agingrelated ailments,neurological diseases,and ophthalmic pathologies.These models hold great promise in advancing biomedical research due to their closer physiological and biochemical resemblance to humans compared to mice.This review aims to summarize the novel gene-editing approaches currently available for rabbits and present the applications and prospects of such models in biomedicine,underscoring their impact and future potential in translational medicine.

Methods to Reduce the Hypoglycemic Mortality of Alloxan in Diabetic Rabbit Model

Objective: To explore an intervention method to reduce the mortality of alloxan diabetes model, and to preliminarily analyze the mechanism of alloxan induced animal death. Methods: Healthy New Zealand rabbits were randomly divided into injection group, control group, experimental group and blank group. The single injection group was injected with 100 mg/kg alloxan once. The control group was given 5% glucose solution and 100 mg/kg alloxan was injected in two times. The experimental group was given 5% glucose solution orally, 100 mg/kg alloxan, 7 mL 0.9% NaCl intravenously and 5 mL 5% glucose intraperitoneally immediately, and blood glucose was continuously monitored, 10 mL 5% glucose intravenously and 10 mL 5% glucose intraperitoneally every 4 h in the hypoglycemic stage. The blank group does nothing. Liver and kidney tissues at different time periods were stained with HE and organ index was evaluated. Results: 1) A single injection of 100 mg/kg alloxan without any intervention resulted in 100% mortality. Before modeling, oral administration of 5% glucose solution, divided into two injections of 100 mg/kg alloxan, mortality reached 100%;A single injection of 100 mg/kg alloxan and continuous intervention of normal saline and glucose for 20 h can significantly reduce the mortality of alloxan induced diabetic rabbit model. 2) Liver and kidney tissues were damaged in different degrees at different time periods, and liver and kidney indexes were significantly increased after alloxan injection compared with the normal group, with statistical significance (P > 0.05). Conclusion: 1) Every 4 hours of hypoglycemia, 10 ml 5% glucose was injected intravenously 10 ml 5% glucose intraperitoneally. It can reduce the death rate of alloxan diabetic rabbit model and shorten the time of blood glucose measurement. 2) After the injection of alloxan, acute lesions of liver and kidney may occur in different degrees, or one of the causes of acute death of experimental animals.

Awake rabbit model of ischemic spinal cord injury with delayed paraplegia:The role of ambient temperature

Background:Paraplegia after spinal cord ischemia is a devastating condition in the clinic.Here,we develop an awake rabbit model of spinal cord ischemia with delayed paraplegia and explore the influence of ambient temperature on the outcomes after injury.Methods:A total of 47 male rabbits were involved in the present study.Transient spinal cord ischemia was induced by occluding the infrarenal abdominal aorta of awake rabbits at different ambient temperatures.To find the optimal conditions for developing delayed paraplegia,hindlimb motor function after ischemia was evaluated between experiments.Results:The onset and magnitude of ischemic injury varied with the ambient temperature maintained during the peri-i schemia period.More serious spinal cord injury occurred when ischemia was induced at higher temperatures.At 18°C,25-minute ischemia resulted in 74%of rabbits developing delayed paraplegia.At a temperature of 28°C or higher,most of the animals developed acute paraplegia immediately.While at 13°C,rabbits usually regained normal motor function without paraplegia.Conclusion:This awake rabbit model is highly reproducible and will be helpful in future studies of delayed paraplegia after spinal cord ischemia.The ambient temperature must be considered while using this model during investigation of therapeutic interventions.

New rabbit model for benign biliary stricture formation with repeatable administration

BACKGROUND The treatment of benign biliary strictures(BBS)is a challenging clinical problem.At present,there is a lack of ideal models for the study of BBS treatment.AIM To develop a novel animal model of BBS to simulate studies on the processes and mechanisms in the human condition.METHODS A rabbit model of benign bile duct stricture was established by surgical injury of the bile duct.After removal of the gallbladder,a drainage tube was placed th-rough the cystic duct at the stump,and a BBS model was induced by surgical injury at the lower end of the common bile duct.RESULTS Compared with the control group,the model rabbits showed gross jaundice,increased serum bilirubin,and decreased liver function.Cholangiography showed segmental bile duct stenosis in the model rabbits.Pathological staining showed inflammatory cell infiltration and fibrosis in the biliary tract of rabbits in the model group.This was consistent with the clinical manifestations of BBS.This model provided serology,imaging,pathology,and other aspects of BBS.CONCLUSION We have successfully established an animal model of benign stricture of the lower bile duct with repeatable administration,which is consistent with the clinical manifestations of BBS.

Propofol Target-Controlled Infusion Modeling in Rabbits:Pharmacokinetic and Pharmacodynamic Analysis

This study aimed to establish a new propofol target-controlled infusion（TCI） model in animals so as to study the general anesthetic mechanism at multi-levels in vivo. Twenty Japanese white rabbits were enrolled and propofol（10 mg/kg） was administrated intravenously. Artery blood samples were collected at various time points after injection, and plasma concentrations of propofol were measured. Pharmacokinetic modeling was performed using Win Nonlin software. Propofol TCI within the acquired parameters integrated was conducted to achieve different anesthetic depths in rabbits, monitored by narcotrend. The pharmacodynamics was analyzed using a sigmoidal inhibitory maximal effect model for narcotrend index（NI） versus effect-site concentration. The results showed the pharmacokinetics of propofol in Japanese white rabbits was best described by a two-compartment model. The target plasma concentrations of propofol required at light anesthetic depth was 9.77±0.23 μg/m L, while 12.52±0.69 μg/m L at deep anesthetic depth. NI was 76.17±4.25 at light anesthetic depth, while 27.41±5.77 at deep anesthetic depth. The effect-site elimination rate constant（ke0） was 0.263/min, and the propofol dose required to achieve a 50% decrease in the NI value from baseline was 11.19 μg/m L（95% CI, 10.25–13.67）. Our results established a new propofol TCI animal model and proved the model controlled the anesthetic depth accurately and stably in rabbits. The study provides a powerful method for exploring general anesthetic mechanisms at different anesthetic depths in vivo.

Pharmacokinetics of Native r-SAK in Rabbit's Femoral Artery Thrombosis Model

Objective: To study the pharmacokinetics of native r SAK in rabbit's femoral artery thrombosis model, the “lytic circle' method was used to determine plasma levels of r SAK. Methods: Thirty New Zealand rabbits were randomly assigned to the control (saline 10 ml, 30 min), r SAK low dose (0.25 mg/kg, 30 min), medial dose (0.50 mg/kg, 30 min), high dose (1.00 mg/kg, 30 min), single bolus (0.50 mg/kg, 2 min) and conjunctive therapy (initiated with heparin 200 U/kg, followed by infusion of r SAK 0.50 mg/kg for 30 min, and subsequently infused heparin 50 U/(kg·h) to endpoint) groups. The right femoral artery thrombosis model in rabbit was made by balloon injury, then the thrombolytic agents were infused through parallel ear vein and the blood samples were collected pre thrombolysis and at different time post thrombolysis to determine the plasma levels of r SAK by “lytic circle' method, the plasma levels of r SAK were processed by pharmacokinetic computing procedure to fit the model. Results: The plasma levels of r SAK and the diameters of lytic circles showed a pretty good linear correlation under the scope of 2.0×10 4 2.0×10 6 U/L, and the averaged recycle rate was (96.05±11.35)%(RSD =±11.82%).All peak concentration time in each infusion group was 30 min, and the peak concentrations positively correlated with the doses administrated in infusion groups(r=0.999 98, P <0.000 1). In single bolus group, Peak concentration time was 2 min, and the peak concentration reached (5.16±1.02) mg/L, which was significant higher than that in the same dose r SAK infusion group ( P <0.01). In conjunctive therapy group, the peak concentration showed no significant difference from that in the same dose r SAK infusion group ( P >0.05). The plasma levels of r SAK fit in two compartment model as processed by pharmacokinetic computing procedure in each group. Conclusion: The “lytic circle' method is a simple, practical and reliable method to determine the plasma level of r SAK, and the pharmacokinetics of native r SAK infusion fits in two compartment model in rabbit's femoral artery thrombosis model.

Evaluation of the Effects of Cypermethrin on Female Reproductive Function by Using Rabbit Model and of the Protective Role of Chinese Propolis

The prophylactic effects of Chinese propolis against cypermethrin toxicity were evaluated by performing ovary and uterus histopathology, as well as by characterizing ovarian function, embryos, and litters. Cypermethrin induced atypia in the ovary and uterus, and decreased the ovulation sites and the number of embryos. Cypermethrin-induced oxidative stress during pregnancy, decreased the parturition rate as well as the number and weight of offspring and increased the incidence of morphological malformations in the offspring. Administration of propolis to cypermethrin-treated animals mitigated cypermethrin-induced reproductive toxicity.

Susceptibility-weighted imaging is suitable for evaluating signal strength in different brain regions of a rabbit model of acute hemorrhagic anemia

Acute hemorrhagic anemia can decrease blood flow and oxygen supply to brain, and affect its physiological function. While detecting changes in brain function in patients with acute hemorrhagic anemia is helpful for preventing neurological complications and evaluating therapeutic effects, clinical changes in the nervous systems of these patients have not received much attention. In part, this is because current techniques can only indirectly detect changes in brain function following onset of anemia, which leads to lags between real changes in brain function and their detection.

Comparison of two different laparotomy methods for modeling rabbit VX2 hepatocarcinoma

AIM:To compare two different laparotomy methods for modeling rabbit VX2 hepatocarcinoma.METHODS:Thirty New Zealand rabbits were randomly divided into two groups:A and B.Group A was assigned a traditional laparotomy method(embedding tumor fragments directly into the liver with tweezers).Group B was subjected to an improved laparotomy method(injection of tumor fragments into the liver through a 15 G syringe needle).The operation time, incision length, incision infection rate, and mortality rate were compared between the two groups after laparotomy.Magnetic resonance imaging(MRI) was performed to evaluate tumor formation rates and the characteristics of the tumors 2 wk after laparotomy.RESULTS:The mean operation times for the two groups(Group A vs Group B) were 23.2 ± 3.4 min vs 17.5 ± 2.9 min(P < 0.05); the incision length was 3.3 ± 0.5 cm vs 2.4 ± 0.6 cm(P < 0.05); and the mortality rate after 2 wk was 26.7% vs 0%(P < 0.05); all of these outcomes were significantly different between the two groups.The incision infection rates in the two groups were 6.7% vs 0%(P > 0.05), whichwere not significantly different.MRI performed after 2weeks showed that the tumor formation rates in the two groups were 90.9%vs 93.3%(P>0.05).These rates were not significantly different between the two groups.The celiac implantation rate and abdominal wall metastasis rate in the two groups were 36.4%vs 13.3%(P<0.05)and 27.2%vs 6.7%(P<0.05),respectively,which were significantly different between the two groups.CONCLUSION:The tumor formation rates were not significantly different between the two methods for modeling rabbit VX2 hepatocarcinoma.However,the improved method is recommended because it has certain advantages.

Experimental and finite element analysis of tibial stress fractures using a rabbit model

AIM: To determine if rabbit models can be used to quantify the mechanical behaviour involved in tibial stress fracture(TSF) development.METHODS: Fresh rabbit tibiae were loaded under compression using a specifically-designed test apparatus. Weights were incrementally added up to a load of 30 kg and the mechanical behaviour of the tibia was analysed using tests for buckling, bone strain and hysteresis. Structural mechanics equations were subsequently employed to verify that the results were within the range of values predicted by theory. A finite element(FE) model was developed using cross-sectional computer tomography(CT) images scanned from one of the rabbit bones, and a static load of 6 kg(1.5 times the rabbit's body weight) was applied to represent running. The model was validated using the experimental strain gauge data, then geometric and elemental convergence tests were performed in order to find the minimum number of cross-sectional scans and elements respectively required for convergence. The analysis was then performed using both the model and the experimental results to investigate the mechanical behaviour of the rabbit tibia under compressive load and to examine crack initiation.RESULTS: The experimental tests showed that un der a compressive load of up to 12 kg, the rabbit tibia demonstrates linear behaviour with little hysteresis Up to 30 kg, the bone does not fail by elastic buckling however, there are low levels of tensile stress which predominately occur at and adjacent to the anterio border of the tibial midshaft: this suggests that fatigue failure occurs in these regions, since bone under cycli loading initially fails in tension. The FE model predic tions were consistent with both mechanics theory and the strain gauge results. The model was highly sensi tive to small changes in the position of the applied load due to the high slenderness ratio of the rabbit s tibia. The modelling technique used in the curren study could have applications in the development o human FE models of bone, where, unlike rabbit tibia the model would be relatively insensitive to very sma changes in load position. However, the rabbit mode itself is less beneficial as a tool to understand the me chanical behaviour of TSFs in humans due to the sma size of the rabbit bone and the limitations of human scale CT scanning equipment.CONCLUSION: The current modelling technique could be used to develop human FE models. However, the rabbit model itself has significant limitations in under standing human TSF mechanics.

Evaluation of a rabbit rectal VX2 carcinoma model using computed tomography and magnetic resonance imaging

AIM： To establish a rabbit rectal VX2 carcinoma model for the study of rectal carcinoma.METHODS： A suspension of VX2 cells was injected into the rectum wall under the guidance of X-ray fluoroscopy. Computed tomography （CT） and magnetic resonance imaging （MRI） were used to observe tumorgrowth and metastasis at different phases. Pathological changes and spontaneous survival time of the rabbits were recorded.RESULTS： Two weeks after VX2 cell implantation, the tumor diameter ranged 4.1-5.8 mm and the success implantation rate was 81.8%. CT scanning showed low-density loci of the tumor in the rectum wail, while enhanced CT scanning demonstrated a symmetrical intensification in tumor loci. MRI scanning showed alow signal of the tumor on T1-weighted imaging anda high signal of the tumor on T2-weighted imaging.Both types of signals were intensified with enhanced MRI. Metastases to the liver and lung could beobserved 6 wk after VX2 cell implantation, and a largearea of necrosis appeared in the primary tumor. The spontaneous survival time of rabbits with cachexia and multiple organ failure was about 7 wk after VX2 cell implantation.CONCLUSION： The rabbit rectal VX2 carcinoma model we established has a high stability, and can be used in the study of rectal carcinoma.

Establishment of a chronic left ventricular aneurysm model in rabbit

Objectives To establish a cost-effective and reproducible procedure for induction of chronic left ventricular aneurysm （LVA） in rabbits. Methods Acute myocardial infarction （AMI） was induced in 35 rabbits via concomitant ligation of the left anterior descending （LAD） coronary artery and the circumflex （Cx） branch at the middle portion. Development of AMI was co n-firmed by ST segment elevation and akinesis of the occluded area. Echocardiography, pathological evaluation, and agar i n-tra-chamber casting were utilized to validate the formation of LVA four weeks after the surgery. Left ventricular end systolic pressure （LVESP） and diastolic pressure （LVEDP） were measured before, immediately after and four weeks after ligation. D i-mensions of the ventricular chamber, thickness of the interventricular septum （IVS） and the left ventricular posterior wall （LVPW） left ventricular end diastolic volume （LVEDV） and systolic volume （LVESV）, and ejection fraction （EF） were recorded by echo-cardiography. Results Thirty one （88.6%） rabbits survived myocardial infarction and 26 of them developed aneurysm （83.9%）. The mean area of aneurysm was 33.4% ＆#177; 2.4% of the left ventricle. LVEF markedly decreased after LVA formation, whereas LVEDV, LVESV and the thickness of IVS as well as the dimension of ventricular chamber from apex to mitral valve annulus significantly increased. LVESP immediately dropped after ligation and recovered to a small extent after LVA formation. LVEDP progressively increased after ligation till LVA formation. Areas in the left ventricle （LV） that underwent fibrosis included the apex, anterior wall and lateral wall but not IVS. Agar intra-chamber cast showed that the bulging of LV wall was prominent in the area of aneurysm. Conclusions Ligation of LAD and Cx at the middle portion could induce develo pment of LVA at a mean area ratio of 33.4%＆#177;2.4%which involves the apex, anterior wall and lateral wall of the LV.

Accelerated and enhanced osteointegration of MAO-treated implants:histological and histomorphometric evaluation in a rabbit model

Microarc oxidation（MAO） has become a promising technique for the surface modification of implants. Therefore, the aims of this study were to further quantitatively and qualitatively evaluate the osteointegration abilities of MAO-treated and smooth surface（SF） implants in vivo and to investigate the areas in which the superiority of MAO-treated implants are displayed. In a rabbit model,a comprehensive histomorphological, osteogenic, mineralizational, and integrative assessment was performed using light microscopy, fluorescence microscopy, confocal laser scanning microscopy, and radiographic analyses. Compared with the SF groups, the MAO-treated groups exhibited more active contact osteogenesis, as well as distant osteogenesis, under fluorescence examination, the mineral apposition rate was found to be greater for all of the MAO-treated implants, and the osteointegration index（OI） value was greater in the MAO-treated groups at different times. In conclusion, the calcium-rich amorphous layer created by MAO provided a better environment for osteointegration, with more active contact osteogenesis, a more rapid mineral apposition rate and greater OI values.

Establishment of VX2 breast carcinoma model in rabbit by injecting tumor mass suspension

Objective: To establish a stable model of VX2 breast carcinoma in rabbit and select the optimal way. Methods: Thirty female New Zealand rabbits were randomly divided into 3 groups with 10 in each. Tumor cell suspensions or tumor mass suspensions were injected into breast tissues of rabbits of group A and B, respectively. Tumor blocks were surgically implanted in rabbit breasts of group C. Tumor formation rate, tumor growth rate, and tumor-bearing survival time was compared, and the histological feature of tumor was observed. Results: Models were established conveniently and successfully in rabbits received injection of tumor mass suspensions. Tumor proliferated rapidly with the biological feature of squamous cell carcinoma. Conclusion: VX2 breast carcinoma model in rabbit was established successfully. Intramammary injection of tumor mass suspension is the best method.

Validation of a preclinical dry eye model in New Zealand white rabbits during and following topical instillation of 1% ophthalmic atropine sulfate

Background : The objective of this study was to validate an animal model for dry eye during and after the administration of 1% ophthalmic atropine sulfate(OAS) in New Zealand white(NZW) rabbits.Methods : OAS(1%) was applied three times per day to 30 eyes of 15 healthy NZW rabbits. Sacrifice, enucleation, and lacrimal gland removal took place on days 15, 21,and 30(OAS group). A second group(n = 5) was used as control. Clinical evaluations took place on days 3, 10, 15, 18, 21, 24 and 30. The primary endpoints were:Schirmer I test, tear break-up time(TBUT), and corneal fluorescein staining. As secondary endpoints, clinical changes including intraocular pressure, and histopathology were evaluated.Results : While OAS was administered, the Schirmer I test showed a statistically significant reduction for OAS group versus control( p < 0.001), and versus basal production( p < 0.001). TBUT showed statistically significant differences between groups(days 3 and 10;p = 0.001) and versus basal values(day 3;p < 0.001). Fluorescein staining showed a statistically significant difference(day 3;p = 0.001). The most frequent clinical finding was conjunctival hyperemia(76.9% OAS vs. 20% control). For histopathology, all OAS subjects presented some degree of inflammation(86.7% minimal;13.3% mild) whereas the control presented only 30% minimal inflammation. Goblet cell density showed no difference.Conclusions : The effectiveness of the OAS dry eye model in NZW rabbits as reported in previous studies was confirmed, provided that the application of the drug is maintained throughout the intervention;it is not a viable model after OAS administration is suspended.

Establishment of Experimental Mastitis Model by Lipopolysaccharide via Teat Duct in Rabbit

[ Objective] This study was conducted to explore the method of establishing Lipopolysaccharide （LPS） -induced mastitis pathological models and reveal dynamic pathological changes of mammary tissue before and after LPS perfusion, finally providing convenient animal models for establishing LPS- induced acute clinical mastitis researches. [ Method] Twelve lactating rabbits （the 7th day after parturition） were perfused with LPS into the fourth mammary gland via the teat duct. Exactly at 2h before perfusion, 6 h, 12 h, 24 h, 48 h, 72 h, 5 d and 7 d after, the indexes such as rectal temperature, total white blood calls and neutrophils, C -response protein （CPR） content and lactate dehydrogenase （LDH） activity were determined, respectively. Then the rabbits were euthanatized and the mammary glands were removed and fixed for histopathologic evalua- tions. [Result] The results showed that inflammatory cells were observed in mammary tissue 6 h after LPS perfusion, structure of mammary tissue disorderly at 24 h, self - regeneration after 48 h and back to normal at 7 d. LDH activity was increasing significantly （ P 〈 0.05） at 12 h （ P 〈 0.05）, peaking at 24 h, decreasing at 5 d （ P 〈 0.05） and returning to health at 7 d. CRP content was increasing significantly （ P 〈 0.05） at 6 to 72 h, pea- king at 12 h, decreasing at 48 h, back to normal at 5 d. [ Conclusion] The results suggested that the rabbit experimental mastitis model was suc- cassfullv constructed bv LPS Derfusion via teat duct.

A Rabbit Model of Hormone-induced Early Avascular Necrosis of the Femoral Head

Objective To establish an experimental model of early stage avascular necrosis of the femoral head （ANFH） caused by corticosteroid in adult rabbits and to observe the pathological changes with various imaging techniques. Methods ANFH was induced by a combination of hypersensitivity vasculitis caused by injection of horse serum and subsequent administration of a high dose of corticosteroid. The pathological changes were detected with digital radiography （DR）, computed tomography （CT）, magnetic resonance imaging （MRI）, ink artery infusion angiography, hematoxylin-eosin staining, and immunohistochemistry. Results The imageological and pathological changes corresponded to the clinical characteristics of early stage ANFH. DR showed bilaterally increased bone density, an unclear epiphyseal line, and blurred texture of cancellous bone. CT showed spot-like low-density imaging of cancellous bone, thinner cortical bone, osteoporosis, and an unclear epiphyseal line. MR! showed bone marrow edema and spot-like high signals in T2-weighted imaging in cancellous bone. Ink artery infusion angiography showed fewer obstructed blood vessels in the femoral head. HE staining of pathological sections showed fewer trabeculae and thin bone, an increased proportion of empty osteocyte lacunae, decreased hematopoiesis, thrombosis, and fat cell hypertrophy. Immunohistochemistry showed attenuated expression of vascular endothelial growth factor in osteoblasts and chondrocytes, and on the inner membrane of blood vessels. Conclusion Experimental rabbit model of early stage ANFH caused by corticosteroid can be successfully established and provide the foundation for developing effective methods to treat early stage ANFH.

Transplantation of tissue-engineered human corneal epithelium in limbal stem cell deficiency rabbit models

AIM: To evaluate the biological functions of tissue-engineered human corneal epithelium (TE-HCEP) by corneal transplantation in limbal stem cell deficiency (LSCD) rabbit models. METHODS: TE-HCEPs were reconstructed with DiI-labeled untransfected HCEP cells and denuded amniotic membrane (dAM) in air-liquid interface culture, and their morphology and structure were characterized by hematoxylin-eosin (HE) staining of paraffin-sections, immunohistochemistry and electron microscopy. LSCD models were established by mechanical and alcohol treatment of the left eyes of New Zealand white rabbits, and their eyes were transplanted with TE-HCEPs with dAM surface outside by lamellar keratoplasty (LKP). Corneal transparency, neovascularization, thickness, and epithelial integrality of both traumatic and post transplantation eyes were checked once a week by slit-lamp corneal microscopy, a corneal pachymeter, and periodic acid-Schiff (PAS) staining. At day 120 post surgery, the rabbits in each group were sacrificed and their corneas were examined by DiI label observation, HE staining, immunohistochemistry and electron microscopy. RESULTS: After cultured for 5 days on dAM, HCEP cells, maintaining keratin 3 expression, reconstructed a 6-7 layer TE-HCEP with normal morphology and structure. The traumatic rabbit corneas, entirely opaque, conjunctivalized and with invaded blood vessels, were used as LSCD models for TE-HCEP transplantation. After transplantation, obvious edema was not found in TE-HCEP-transplanted corneas which became more and more transparent, the invaded blood vessels reduced gradually throughout the monitoring period. The corneas decreased to normal thickness on day 25, while those of dAM eyes were over 575 mu m in thickness during the monitoring period. A 45 layer of epithelium consisting of TE-HCEP originated cells attached tightly to the anterior surface of stroma was reconstructed 120 days after TE-HCEP transplantation, which was similar to the normal control eye in morphology and structure. In contrast, intense corneal edema, turbid, invaded blood vessels were found in dAM eyes, and no multilayer epithelium was found but only a few scattered conjunctiva-like cells appeared. CONCLUSION: The TE-HCEP, with similar morphology and structure to those of innate HCEP, could reconstruct a multilayer corneal epithelium with normal functions in restoring corneal transparency and thickness of LSCD rabbits after transplantation. It may be a promising HCEP equivalent for clinical therapy of corneal epithelial disorders.

Early changes of hepatic hemodynamics measured by functional CT perfusion in a rabbit model of liver tumor

BACKGROUND:Early detection and treatment of hepatocellular carcinoma is crucial to improving the patients’ survival.The hemodynamic changes caused by tumors can be serially measured using CT perfusion.In this study,we used a CT perfusion technique to demonstrate the changes of hepatic hemodynamics in early tumor growth,as a proof-of-concept study for human early hepatocellular carcinoma.METHODS:VX2 tumors were implanted in the liver of ten New Zealand rabbits.CT perfusion scans were made 1 week(early) and 2 weeks(late) after tumor implantation.Ten normal rabbits served as controls.CT perfusion parameters were obtained at the tumor rim,normal tissue surrounding the tumor,and control liver;the parameters were hepatic blood flow,hepatic blood volume,mean transit time,permeability of capillary vessel surface,hepatic arterial index,hepatic arterial perfusion and hepatic portal perfusion.Microvessel density and vascular endothelial growth factor were correlated.RESULTS:At the tumor rim,compared to the controls,hepatic blood flow,hepatic blood volume,permeability of capillary vessel surface,hepatic arterial index,and hepatic arterial perfusion increased,while mean transit time and hepatic portal perfusion decreased on both early and late scans(P<0.05).Hepatic arterial index increased(135%,P<0.05),combined with a sharp increase in hepatic arterial perfusion(182%,P<0.05) and a marked decrease in hepatic portal perfusion(-76%,P<0.05) at 2 weeks rather than at 1 week(P<0.05).Microvessel density and vascular endothelial growth factor showed significant linear correlations with hepatic blood flow,permeability of capillary vessel surface and hepatic arterial index,but not with hepatic blood volume or mean transit time.CONCLUSION:The CT perfusion technique demonstrated early changes of hepatic hemodynamics in this tumor model as proof-of-concept for early hepatocellular carcinoma detection in humans.