Adult Female Rabbits Research Articles

Pancreatic inflammation induced by hypothyroidism in female rabbits is associated with cholesterol accumulation and a reduced expression of CYP51A1, FXRβ, and PPARβ/δ.

In women and animal models, hypothyroidism induces hypercholesterolemia, pancreatitis, and insulitis. We investigated whether lipids are involved in the effects of hypothyroidism in the pancreas. Control (n = 6) and hypothyroid (n = 6) adult female rabbits were used. We quantified serum and pancreatic triacylglycerol and total cholesterol levels, the oxidative and antioxidant status, and the expression of low-density lipoprotein cholesterol receptor (LDLR) in the pancreas. Inflammation of the pancreas was evaluated by infiltration of immune cells positive to CD163 and α-farnesoid receptor (FXRα). Other lipid players involved in both inflammation and insulin secretion of the pancreas, such as lanosterol 14-α-demethylase (CYP51A1), β-farnesoid receptor (FXRβ), 3β-hydroxysteroid dehydrogenase (3β-HSD), and peroxisome proliferator-activated receptor β (PPARβ/δ), were quantified. Groups were compared by t-Student or U-Mann-Whitney tests (p ≤ 0.05). Hypothyroidism induced hypercholesterolemia and a high cholesterol accumulation in the pancreas of female rabbits, without affecting oxidative or antioxidative status nor the expression of LDLR. The pancreas of hypothyroid females showed inflammation identified by a great infiltration of immune cells, macrophages CD163+, and loss of expression of FXRα+ in immune cells. Moreover, a reduced expression of CYP51A1, FXRβ, and PPARβ/δ, but not 3β-HSD, in the hypothyroid pancreas was found. Pancreatitis and insulitis promoted by hypothyroidism may be related to the accumulation of cholesterol, lanosterol actions, and the activation of PPARβ/δ. All inflammatory markers evaluated in this study are related to glucose regulation, suggesting the link between hypothyroidism and diabetes.

Neurodegeneration in a domestic rabbit with severe malnourishment and low hepatic copper.

Copper is a trace element that plays an essential role in neurodevelopment and neurologic function. Acquired copper deficiency has a range of neurologic manifestations, with myelopathy being the most common association. We describe here the clinical, radiologic, histopathologic, and toxicologic findings of a rabbit with malnutrition, neurodegeneration, and suspected copper deficiency. A stray, adult female dwarf rabbit cross (Oryctolagus cuniculus) in poor body condition developed ataxia and pelvic limb weakness progressing to lateral recumbency and urine retention. The clinical findings suggested multifocal brainstem disease with right-sided central vestibular involvement; however, microscopic examination identified thoracic and lumbosacral spinal cord myelopathy. Differentials for the spinal cord changes included neurodegenerative disease, nutritional deficiency, neurotoxin, trauma to the lumbosacral region, and ischemia. Hepatic copper levels were suboptimal at 18 ppm dry weight (RI: 24-150 ppm dry weight). While speculative, copper-deficiency myelopathy is a treatable cause of non-compressive myelopathy that may occur in this species.

Osteointegration of functionalised high-performance oxide ceramics: imaging from micro-computed tomography

BackgroundThis study evaluated the osseointegration potential of functionalised high-performance oxide ceramics (HPOC) in isolation or coated with BMP-2 or RGD peptides in 36 New Zeeland female rabbits using micro-computed tomography (micro CT). The primary outcomes of interest were to assess the amount of ossification evaluating the improvement in the bone volume/ total volume (BV/TV) ratio and trabecular thickness at 6 and 12 weeks. The second outcome of interest was to investigate possible differences in osteointegration between the functionalised silanised HPOC in isolation or coated with Bone Morphogenetic Protein 2 (BMP-2) or RGD peptides.Methods36 adult female New Zealand white rabbits with a minimum weight of three kg were used. One-third of HPOCs were functionalised with silicon suboxide (SiOx), a third with BMP-2 (sHPOC-BMP2), and another third with RGD (sHPOC-RGD). All samples were scanned with a high-resolution micro CT (U-CTHR, MILabs B.V., Houten, The Netherlands) with a reconstructed voxel resolution of 10 µm. MicroCT scans were reconstructed in three planes and processed using Imalytics Preclinical version 2.1 (Gremse-IT GmbH, Aachen, Germany) software. The total volume (TV), bone volume (BV) and ratio BV/TV were calculated within the coating area.ResultsBV/TV increased significantly from 6 to 12 weeks in all HPOCs: silanised (P = 0.01), BMP-2 (P < 0.0001), and RGD (P < 0.0001) groups. At 12 weeks, the BMP-2 groups demonstrated greater ossification in the RGD (P < 0.0001) and silanised (P = 0.008) groups. Trabecular thickness increased significantly from 6 to 12 weeks (P < 0.0001). At 12 weeks, BMP-2 promoted greater trabecular thickness compared to the silanised group (P = 0.07), although no difference was found with the RGD (P = 0.1) group.ConclusionSinalised HPOC in isolation or functionalised with BMP-2 or RGD promotes in vivo osteointegration. The sinalised HOPC functionalised with BMP-2 demonstrated the greatest osseointegration.

Effect of Parasteron on In Vivo Atherosclerotic model with Functional and Tissue Damage Mitigation

Background: Atherosclerosis, a leading cause of cardiovascular diseases, involves the buildup of plaques within arterial walls, leading to functional and tissue damage. Animal models, particularly rabbits, have been instrumental in studying this disease due to their lipoprotein metabolism and sensitivity to a cholesterol diet, similar to humans. The current study aims to evaluate the effects of the steroid hormone parasteron on the functional and tissue damage caused by atherosclerosis in adult female rabbits. Methods: The study was conducted over six weeks on four groups of adult female rabbits. The first group served as the control, while the second group was administered cholesterol to induce atherosclerosis. The third and fourth groups were treated with both cholesterol and the steroid hormone parasteron. Various parameters related to atherosclerosis, including functional metrics and tissue damage, were monitored and analyzed. Results: The control group showed no signs of atherosclerosis or tissue damage. The cholesterol-only group exhibited significant functional impairments and tissue damage characteristic of atherosclerosis. In the groups treated with parasteron, there was a notable reduction in both functional impairments and tissue damage compared to the cholesterol-only group. The extent of protection provided by parasteron was assessed through histological and biochemical analyses, which revealed a marked improvement in arterial health and function. Conclusion: The administration of parasteron significantly mitigates the functional and tissue damage associated with atherosclerosis in adult female rabbits. These findings suggest the potential of parasteron as a therapeutic agent in the management of atherosclerosis. Further research is warranted to explore the underlying mechanisms and to evaluate the long-term efficacy and safety of parasteron in larger clinical settings.

A novel micro-CT analysis for evaluating the regenerative potential of bone augmentation xenografts in rabbit calvarias

Guided Bone Regeneration is a common procedure, yet, as new grafting materials are being introduced into the market, a reliable evaluation method is required. Critical size defect in animal models provides an accurate simulation, followed by histological sections to evaluate the new bone formation. However, histology is destructive, two-dimensional and technique-sensitive. In this study we developed a novel volumetric Micro-CT analysis to quantify new bone formation characteristics. Eight adult female New Zealand white rabbits were subjected to calvarial critical-size defects. Four 8 mm in diameter circular defects were preformed in each animal, to allow random allocation of four treatment modalities. All calvarias were scanned using Micro-CT. Each defect was segmented into four equal parts: pristine bone, outer, middle, and inner. Amira software (v. 6.3, www.fei.com) was used to calculate the new bone volume in each region and compare it to that of the pristine bone. All grafting materials demonstrated that new bone formation decreased as it moved inward. Only the inner region differed across grafting materials (p = 0.001). The new Micro-CT analysis allowed us to divide each defect into 3D regions providing better understanding of the bone formation process. Amongst the various advantages of the Micro-CT, it enables us to quantify the graft materials and the newly formed bone independently, and to describe the defect morphology in 3D (bi- vs. uni-cortical defects). Providing an insight into the inner region of the defect can better predict the regenerative potential of the bone augmentation graft material. Therefore, the suggested Micro-CT analysis is beneficial for further developing of clinical approaches.

Effects of dietary substitution of Soybean meal by dried Azolla on blood and serum parameters, productive and reproductive traits, and economic efficiency of rabbit does as well as semen quality of bucks

An experiment was carried out to investigate the effects of dietary substitution of dried Azolla (Azolla pinnata) in different ratios by soybean meal on productive and reproductive performances, hematological and serum traits, and economic efficiency of rabbit does as well as semen quality of males. Forty mature does and eight males of Black Balady rabbits aged seven and eight months were assigned to 1 of 4 dietary groups: 0 (control), 20, 30, and 40% of soybean protein substituted with dried Azolla protein. Data were analyzed using repeated measures of statistical software computer program package. There were no significant differences among groups in number of services per conception as well as parturition intervals (days) with a superiority of 30% group over the control and other two groups. Average litter weight was significantly (P&lt;0.05) superior in the 30% replacement group. There were no significant differences in live body weight either at birth or at weaning among the four tested groups and the 30% replacement groups recorded the highest significant daily weight gain of bunnies during the whole experimental period. All Azolla groups recorded better results in the studied traits of bucks' semen compared to the control. Azolla diets did not show any adverse effects on the studied blood parameters. The 30% replacement of the soybean protein group showed the best economic return compared to the other two replacement groups and the control. In conclusion, Azolla can safely and economically replace soybean protein at the rate of 30% in adult female rabbits' diets. Keywords: Azolla, Body weight, Rabbit, Reproduction, Semen.

A biomechanical assessment of tissue-engineered polymer neo-uteri after orthotopic implantation

To assess the invivo biomechanical maturation of tissue-engineered neo-uteri that have previously supported live births in a rabbit model. Nonclinical animal study. University-based research laboratory. Eighteen adult female rabbits. Biodegradable poly-DL-lactide-co-glycolide-coated polyglycolic acid scaffolds seeded with autologous uterine-derived endometrial and myometrial cells. Nonseeded scaffolds and seeded, tissue-engineered neo-uteri were implanted into one uterine horn of rabbits for 1, 3, or 6 months, excised, and biomechanically assessed in comparison to native uterine tissue. Tensile stress-relaxation testing, strain-to-failure testing, and viscoelastic modeling. By evaluating the biomechanical data with several viscoelastic models, it was revealed that tissue-engineered uteri were more mechanically robust than nonseeded scaffolds. For example, the 10% instantaneous stress of the tissue-engineered neo-uteri was 2.1 times higher than the nonseeded scaffolds at the 1-month time point, 1.6 times higher at the 3-month time point, and 1.5 times higher at the 6-month time point. Additionally, as the duration of implantation increased, the engineered constructs became more mechanically robust (e.g., 10% instantaneous stress of the tissue-engineered neo-uteri increased from 22 kPa at 1 month to 42 kPa at 6 months). Compared with native tissue values, tissue-engineered neo-uteri achieved or surpassed native tissue values by the 6-month time point. The present study evaluated the mechanical characteristics of novel tissue-engineered neo-uteri that have previously been reported to support live births in the rabbit model. We demonstrate that the biomechanics of these implants closely resemble those of native tissue, giving further credence to their development as a clinical solution to uterine factor infertility.

Reinforcing structures proliferated around a titanium implant inserted into the femur of female rabbits, in a hole smaller than the screw core

One of the basic conditions for the clinical success of osseo-integrated implants is implant stability (Albrektsson and Zarb, 1993). It comprises two components, the primary stability that should be ensured at the time of insertion and the secondary stability, which gradually replaces the primary stability. The primary stability is ensured by the direct contact between the implant surface and that of the bone walls of the insertion hole. Secondary stability begins with the first position of new bone on the implant surface. The aim of the present study was to verify the reinforcing structures proliferated around the titanium implant inserted into the femur of 5 adult female rabbits, in a groove smaller than the screw core diameter. The results suggested that inserting the titanium implant into a hole with a smaller diameter than the screw core produces excessive pressure on the bone, which is felt up to a distance from the bone-implant interface. Consequently, mechanical strength of the bone is decreasing and proliferating bone consolidation formations appears on both periosteum and endosteum areas. Additionally, it was observed that newly proliferated bone extends laterally from the interface to a great distance, causing thickening of the bone wall. The observed structures were represented by branched bone trabeculae and bony protrusions into the medullary cavity, together with bone reshuffling processes with the appearance of numerous osteons, most of which are present at the level of the wall opposite the insertion area.

Preventive Effect of Molecular Iodine in Pancreatic Disorders from Hypothyroid Rabbits.

Pancreatic alterations such as inflammation and insulin resistance accompany hypothyroidism. Molecular iodine (I2) exerts antioxidant and differentiation actions in several tissues, and the pancreas is an iodine-uptake tissue. We analyzed the effect of two oral I2 doses on pancreatic disorders in a model of hypothyroidism for 30 days. Adult female rabbits were divided into the following groups: control, moderate oral dose of I2 (0.2 mg/kg, M-I2), high oral dose of I2 (2.0 mg/kg, H-I2), oral dose of methimazole (MMI; 10 mg/kg), MMI + M-I2,, and MMI + H-I2. Moderate or high I2 supplementation did not modify circulating metabolites or pancreatic morphology. The MMI group showed reductions of circulating thyroxine (T4) and triiodothyronine (T3), moderate glucose increments, and significant increases in cholesterol and low-density lipoproteins. Acinar fibrosis, high insulin content, lipoperoxidation, and overexpression of GLUT4 were observed in the pancreas of this group. M-I2 supplementation normalized the T4 and cholesterol, but T3 remained low. Pancreatic alterations were prevented, and nuclear factor erythroid-2-related factor-2 (Nrf2), antioxidant enzymes, and peroxisome proliferator-activated receptor gamma (PPARG) maintained their basal values. In MMI + H-I2, hypothyroidism was avoided, but pancreatic alterations and low PPARG expression remained. In conclusion, M-I2 supplementation reestablishes thyronine synthesis and diminishes pancreatic alterations, possibly related to Nrf2 and PPARG activation.

Ultra Sonographic Study of Kidney Changes Following Experimental Cryogenic Partial Nephrectomy in a Rabbit Model

Background and Objective: Treatment of some limited kidney neoplasms is a partial kidney resection called a partial nephrectomy. One of the concerns in partial nephrectomy is severe and uncontrolled hemorrhage that sometimes results in kidney removal. Cryosurgery is one of the less invasive methods for the management of small kidney lesions, during which the controlled freezing of unwanted tissues will eventually lead to necrosis and gradual destruction of the lesion.The advantages of the cryosurgery method are easy implementation, no thermal ischemia damage during the operation, and no need to cut and suture the kidney parenchyma. Materials and Methods: In this experimental intervention research, the caudal pole of the left kidney of 9 adult female rabbits was subjected to cryogenic partial nephrectomy through a lateral laparotomy. Rabbits were evaluated by ultrasound on 1, 3, 7, 14, 21, and 28 days after surgery to record and observe the extent of kidney damage and healing in the Sagittal and Dorsal sections. Several parameters, such as kidney length dimensions, size of the caudal cortex, and cranial cortex of the kidney, were measured and recorded. Results: Kidney length on days 1, 21, and 28 was significantly less than day 0. On the 7th day after surgery, 2 separate areas, damaged and frozen necrotic tissue (caudal cortex) and healthy and normal kidney tissue were visible. The size of the caudal cortex from day 14 onwards was significantly less than day 0. The process of significant changes in the caudal cortex of the kidney started from day 14 of surgery and the border between dead and living tissue (Line of Demarcation) was distinguishable as a transition zone. On the 21st day after surgery, both the length of the kidney and the caudal cortex decreased significantly compared to day 0. Gradual loss of the caudal pole of the kidney (caudal cortex, the place where cryosurgery was performed directly) showed the applicability of cryosurgery in surgeries during which the tumor was removed (tumor ablation). On the 28th day after surgery, due to gradual necrosis and the loss of the caudal pole of the kidney, the kidney looked like a bitten apple, and the results of changes in the dimensions of the kidney (caudal cortex and length of the kidney) indicated necrosis of the caudal pole of the kidney, which finally led to the shrinking of the kidney. Conclusion: Ultrasonographic study of kidney injury and healing showed that cryosurgery, in addition to tumor ablation, would also have the ability to remove peripheral tissues (partial nephrectomy).

Translated article] Design and comparison of bone substitutes. Study of in vivo behaviour in a rabbit model

AimTo compare the in vivo bone formation capacity of of biomaterials designed as bone substitutes with respect to iliac crest autograft, one based on carbonate hydroxiapatite and the other one on bioactive mesoporous glass. Materials and methodsExperimental study consisting on 14 adult female New Zeland rabbits where a critical defect was made in the rabbit radius bone. The sample was divided into four groups: defect without material, with iliac crest autograft, with carbonatehydroxyapatite scaffold, and with bioactive mesoporous glass scaffold. Serial X-ray studies were carried out at 2, 4, 6 and 12 weeks and a microCT study at euthanasia at 6 and 12 weeks. ResultsIn the X-ray study, autograft group showed the highest bone formation scores. Both groups of biomaterials presented bone formation similar and greater than the defect without material, but always less than in the autograft group. The results of the microCT study showed the largest bone volume in the study area in the autograft group. The groups with bone substitutes presented greater bone volume than the group without material but always less than the autograft group. ConclusionBoth scaffolds seem to promote bone formation but are not capable of reproducing the characteristics of autograft. Due to their different macroscopic characteristics, each one could be suitable for a different type of defect.

Effect of Feeding Pomegranate (Punica granatum) Peel and Garlic (Allium sativum) on Antioxidant Status and Reproductive Efficiency of Female Rabbits

Egypt's animal protein shortfall cannot be overcome by expanding the production of large animals alone, but rather by increasing the production of highly reproducing animals in the livestock unit. The goal of this study was to examine how adding pomegranate peel (PP), garlic powder (GP), or a mixture of the two to the diet of does affect their weight, the number of offspring, reproductive performance, hematological indices, and several antioxidants indicators as well as the liver and kidney functions. A total of 20 adult and mature female mixed rabbits at age 4.5-5 months and averaging 3.05 ± 0.63 kg body weight, were allocated into four experimental groups (n = 5). The first group was provided with the basal diet and was considered as control animals, while the second, third, and fourth groups were fed the basal diet supplemented with PP 3.0%, GP 3.0%, and a mixture of PP 1.5% + GP 1.5%, respectively. After 2 weeks of feeding the experimental diets, natural mating with untreated bucks was carried out. The kits were weighed immediately after parturition, and then every week. The study found that rabbits fed with 3% PP led to a 28.5% increase in the number of kits at birth compared to the control group. As an effect of supplementing PP 3%, GP 3%, and PP 1.5% + GP 1.5%, the birth weight increased by 9.2%, 7.2%, and 10.6%, respectively, as compared to the control. Hemoglobin increased significantly in all treatment groups as compared to the control at the age of kit weaning. Lymph cells increased significantly in the rabbits that were fed with GP (3%) than in other groups and even the control. The results showed that creatinine levels were significantly decreased in the PP (3%) and GP (3%) than in control rabbits. The level of triglycerides significantly declines in groups treated with PP (3%) than in other treatment groups and the control. The addition of PP 3% or GP 3% increased the progesterone hormone. The addition of PP 1.5% + GP 1.5% improved the immunoglobulin IgG. The results of superoxide dismutase, catalase, glutathione, and total antioxidant capacity showed a significant decline in groups treated with GP (3%) than other treated groups. In conclusion, pomegranate is a promising substance to include in a rabbit's diet, followed by garlic to boost reproductive efficiency.

Biochemical and experimental Study for the effect of Date Palm Pollen grains and isolated flavonoids on the levels of steroid hormones in sera of Adult females Rabbits

The effect of DPP grains, isolated flavonoids were carried out on the levels of steroid hormone and Lipid profile in sera of adult female rabbits.&#x0D; This animals were divided into seven groups, which include. acontrol group, G1,G2,G3:groups which orally treated with (12,24,36)mg/kg/day of DPP grain while groupsG4,G5,G6:orally treated with (5,10,15) mg/kg/day of isolated DDP.&#x0D; -Testosterone significantaly increased in G3,G4,G6 as compared with C while with no significant change in other groups.&#x0D; -Estradiol significantaly increased in G2 as compared with C and Significantaly decreased in G3,G4,G5, G6 as compared with C .&#x0D; -progesterone significantaly increased in G3,G4,G5,G6 as compared with C .&#x0D; -Prolactin significantaly decreased in G2,G4,G5,as compared with C.

Diseño y comparativa de biomateriales para el tratamiento de defectos óseos. Estudio de su comportamiento in vivo en modelo animal de conejo

AimCompare bone formation capacity in vivo of two types of biomaterials designed as bone substitutes with respect to iliac crest autograft, one based on carbonate hydroxyapatites and the other one on bioactive mesoporous glass. Materials and methodsExperimental study consisting on 14 adult female New Zeland rabbits where a critical defect was made in the rabbit radius bone. The sample was divided into four groups: defect without material, with iliac crest autograft, with carbonatehydroxyapatite support, and with bioactive mesoporous glass support. Serial X-ray studies were carried out at 2, 4, 6 and 12 weeks and a microCT study at euthanasia at 6 and 12 weeks. ResultsIn the X-ray study, autograft group showed the highest bone formation scores. Both groups of biomaterials presented bone formation similar and greater than the defect without material, but always less than in the autograft group. The results of the microCT study showed the largest bone volume in the study area in the autograft group. The groups with bone substitutes presented greater bone volume than the group without material but always less than in the autograft group. ConclusionBoth supports seem to promote bone formation but are not capable of reproducing the characteristics of autograft. Due to their different macroscopic characteristics, each one could be suitable for a different type of defect.

Reproductive Performance Status of Adult Female Rabbits Administration Spirulina and Combination of Folic acid, B6 and B12

The current study aimed to evaluate the effects of oral administration of spirulina (as a food supplement) on the reproductive performance of adult female rabbits. Female rabbits (16 to 18 weeks old) were divided into three groups (10 rabbits/ group). These groups are: (Gr.I) as a control group and (Gr. II) spirulina was given at a dose (0.5 g / kg of body weight) and (Gr. III) was given a complex of folic acid, B6 and B12 (2.5 + 50 +1 mg / kg body weight) all groups were treated for four weeks. At the end of the treatment period, 2 untreated males (two males/ group) were naturally mated with treated females. The results showed that there was no significant difference in the estrogen concentrations among all groups, while the progesterone concentration showed a significant decrease in the third compound group compared to the control group and DXN-spr. Also, the testosterone hormones did not show significant differences in all groups. FSH and LH concentrations appeared to be significantly decreased in the third group than in the other two groups. The fertility rate and the number of female fertilities increased in the second group (DXN-Spr.) compared to the other groups. There was also a significant increase in birth weight and fertility rate in this group compared to the control and group No. 3 groups. We conclude that oral dosed spirulina (0.5 g/kg body weight) acts as a natural antioxidant that improves reproductive efficiency and reproductive hormones.

Oxidative stress induced cardiomyocytes injury by Tamoxifen and abrogates by zinc supplement in adult female rabbits

Tamoxifen (TAM) is used in breast cancer chemotherapy since its approval by the Food and Drug Administration in 1977. However, TAM therapy is accompanied with cardiomyocytes apoptosis. Oxidative stress and inflammation are the major implicated mechanisms contributing to TAM apoptosis. In this study, we explored whether zinc (Zn) supplementation could prevent TAM-induced cardiomyocytes injury in adult female rabbits. Rabbits were received zinc orally (0.3 mg/ kg body weight / day for 42 days) in zinc group, Tamoxifen group were received orally (0.25 mg/ kg body weight for 42 days), and combination (Zn+Tam) group were received equal dose from zinc and tamoxifen. To study the effect of the tamoxifen (selective estrogen receptor modulator) on the cardiac muscle. Results showed of histopathological study of heart taken from zinc treated group not showed any important abnormalities in histological appearance, tamoxifen group in heart tissue showed a massive necrotic tissue and a huge inflammatory cell infiltration to damaged area and combination group lesion showed active inflammatory process which included blood vessels congestion, edema formation, inflammatory cell aggregation especially macrophage and Myocyte vacuolization. As a consequence, the finding of the research Tam induction over production of reactive oxygen species (ROS) within cardiac cell and the imbalance between the ROS generating system and the antioxidant system can lead to a potentially harmful to tissues and cells.

P06-15 Exposure to a complex and human-relevant mixture of eight environmental toxicants during folliculogenesis alters ovarian follicular populations in the young adult female rabbit

P06-15 Exposure to a complex and human-relevant mixture of eight environmental toxicants during folliculogenesis alters ovarian follicular populations in the young adult female rabbit

Ovarian, uterine, and luteal vascular perfusions during follicular and luteal phases in the adult cyclic female rabbits with special orientation to their histological detection of hormone receptor

Understanding the does reproductive hemodynamic changes during the estrous cycle is crucial for improving reproductive competence and fertility potential in this species. The objective of this study is to investigate the hemodynamic variations in ovarian (OA) and uterine (UA) arteries, histological and morphometric changes in ovarian and uterine tissues throughout the follicular (FP) and luteal (LP) phases in rabbits and determine estrogen (ER), progesterone (PR) receptors, and vascular endothelial growth factor (VEGF) distributions using immunohistochemistry.Fourteen adults pluriparous New Zealand rabbits were divided into rabbits at the FP (Day − 1; n = 7) and those at the LP (Day 9; n = 7). Animals were subjected to Doppler, hormonal (estrogen [E2], progesterone [P4], insulin-like growth factor [ILGF], and VEGF), histological, and immunohistochemical analyses. In LP, OA Doppler indices were significantly increased, whereas peak systolic velocity (PSV) was decreased compared with that in FP. UA Doppler indices were significantly decreased in the LP, whereas PSV was increased (P < 0.05). E2 levels were increased in the FP, whereas P4 levels were increased in the LP. The morphometric analysis of uterine tissues during the LP revealed an increase in the mean uterine endometrium length, endometrial connective tissue area percentage (%), endometrial glands number, myometrial area (%) and thickness. Furthermore, ovarian follicles and corpus luteum (CL) displayed strong positive immunoreactivity for ER, PR, and VEGF-A during both phases. The ovarian sections displayed a substantial (P < 0.05) increase in the area % of VEGF-A in the ovarian follicles during FP while in the CL during LP. Conversely, area percentage of VEGF-A immunoreactivity in the uterine luminal and glandular epithelia during the FP and LP revealed no differences. However, the number of VEGF-A–stained blood capillaries revealed an increase during LP than FP. In conclusion, this study demonstrated for the first time the changes in both ovarian and uterine arteries during two different phases of the rabbit cycle in relation to the histo-morphometric analysis and distribution of ER, PR, and VEGF-A, which regulate uterine functions that play a role in reproduction.

Method of measuring effects of study procedures in single and pair housed New Zealand White rabbits (Oryctolagus cuniculus)

Social housing of laboratory rabbits is encouraged and thought to improve animal welfare due to the social nature of this species. However, there is limited published information comparing the physiologic and cardiovascular (CV) effects of paired and single housed adult female rabbits in commonly used laboratory caging. This study describes measurement of heart rate, systolic blood pressure, activity level, body temperature and pairing methods in four female New Zealand White rabbits that were previously implanted with M10 cardiovascular telemetry devices. Data was collected in single housed rabbits having no history of social housing while they were undisturbed in the home cage, during restraint, intramuscular injections and intravenous blood collection. The same animals were then placed in compatible pairs and housed in conventional Allentown caging. As expected, we found increased activity in paired rabbits but no significant differences in body temperatures, and CV parameters in single and paired rabbits undergoing the same procedures. These data suggest that paired rabbits can be used for safety pharmacology studies with minimal impact to data, while supporting improved animal welfare.

370 Developing a Digitally Integrated Endotracheal Tube for Neonates to Improve Safety and Respiratory Function

OBJECTIVES/GOALS: Neonatal endotracheal tubes (ETTs) are usually uncuffed to avoid subglottic stenosis and other complications, but cuffed ETTs allow better ventilation. Our goal was to detect and control pressure in the cuff below the limit of occluding venous flow to minimize the risk of subglottic stenosis. METHODS/STUDY POPULATION: We designed a pressure sensor to fit on a 2.5 ETT for prototype testing in 8 age adult female rabbits. Eight uncuffed age- and sex- matched rabbits served as control. Study duration was 2 hours during which pressure in the cuff was limited by novel sensor (intervention) or auscultation (control). Anesthesia was maintained with sevoflurane. Ventilation was provided mechanically. Subsequently the tracheae were removed, sectioned crosswise, and compared histologically for mucosal damage. RESULTS/ANTICIPATED RESULTS: Preliminary data demonstrated an almost 30% greater amount of intact mucosa in the intervention group. The sensor also provided data on heart rate and respiratory rate, although this signal was not optimal. After filing an invention disclosure and provisional patent, we are refining our device to include multiple compartments for local control of cuff pressure and applying for a STTR Phase I/II application. DISCUSSION/SIGNIFICANCE: Ventilation in neonates with uncuffed ETTs can be suboptimal due to leak around the tube, but cuffed ETTs pose the threat of subglottic stenosis and other complications. We have designed a prototype cuffed ETT with a sensor to maintain low cuff pressure while preventing leaks and largely avoiding damage to the tracheal mucosa.