Adult Rabbits Research Articles

ST-Segment Alterations in the Electrocardiogram of Acute Pulmonary Thromboembolism: A Rabbit Model

In this study, we investigated the mechanism underlying electrocardiogram (ECG) alterations in a rabbit model of acute pulmonary thromboembolism (PTE). Twelve healthy adult New Zealand white rabbits were used, with eight in the experimental group (PTE group) and four in the control group. After developing the rabbit model of acute PTE, ECG and coronary angiography were performed. HE staining was conducted on the right and left ventricular tissues, and polymerase chain reaction (PCR) was used to determine brain natriuretic peptide (BNP), tumor necrosis factor-alpha (TNF-α), and Troponin I (TNI) mRNA expression in the myocardium. There were considerable changes in the ST segment of the ECG in the PTE group. Coronary angiography revealed the absence of spasm, stenosis, and occlusion. In the plasma of the PTE group, the levels of D-dimer, BNP, TNF-α, and TNI were significantly elevated, and these changes were statistically significant (P<0.05). PCR analysis of ventricular myocardial tissue indicated significantly higher levels of BNP, TNF-α, and TNI mRNA in the PTE group than in the control group. These differences were statistically significant (P<0.05). The ST-T variations on the ECG of rabbits with acute PTE correlate strongly with the temporary changes in right heart volume caused by acute PTE.

The Effect of Gold Nanoparticles and Apricot Kernel Extract on the Osseointegration of Dental Implants - A Rabbit Model

Introduction The osseointegration of dental implants is critical to their longevity and success. Various factors such as surface modifications, both additive and subtractive, systemic drug administration, growth factors, and plasma derivatives can influence osseointegration. Aims and Objectives This study aimed to study the effects of gold nanoparticles and aqueous extract of apricot kernels on the osseointegration of titanium implants in the tibia of rabbits. Materials and Methods Apricot kernels were dried, grounded, and dissolved in water to obtain an aqueous extract. It was filtered and stored in the refrigerator at 4oC. Gold nanoparticles (AuNPs) were prepared by mixing 3 ml of 0.02 mM hydrogen tetrachloroaurate with 1 ml of olive leaf extract. The mixture was stirred vigorously for 15 minutes on a heater stirrer at 50oC. Titanium screw implants were sterilized in an autoclave at 120oC with 15 pounds per square inch for 30 minutes. Sterilized implants were stored in sealed containers until use. The study was carried out at the College of Veterinary Medicine, University of Mosul, Iraq. The ethical approval for the study was obtained from the institutional animal care and use committee, College of Veterinary Medicine, University of Mosul, Mosul, Iraq, on 15/04/2023 on reference no UM.VET.2023.013. Nine healthy male adult white New Zealand rabbits aged between 10-12 months were utilized for the study. Three pure titanium implants, each of a type, were placed in each tibia. The implants were categorized as follows: control group (18 uncoated implants) and experimental group (36 coated implants). The implant placement was divided into three groups: controls with uncoated implants (n=18), AuNPs-coated implants (n=18), and apricot kernel extract-coated implants (n=18). General anesthesia was induced by intramuscular injection of ketamine hydrochloride 50mg (1ml /kg of body weight) plus xylazine 2% (0.2 ml /kg of body weight). The AuNPs-coated implants were implanted in the superior osteotomy site in the tibia. The apricot kernel extract-coated implants were implanted in the inferior osteotomy site and the uncoated implants were implanted in the middle osteotomy sites. Histological and histomorphometric tests were performed on all bone implant blocks at one-week, two-week, and three-week intervals after implant placement. The results were evaluated based on the amount of bone formation, cellular components, and inflammation. Tabulated data were statistically analyzed using SPSS v23.0 (IBM, Armonk, NY) using ANOVA with a statistical significance of p <0.05 Results We observed a significant amount of osteogenesis with reduced inflammation in AuNPs-coated implants and apricot kernel extract-coated implants compared to untreated implants. The osteoclastic activity was significantly higher in untreated implants than the treated implant sites. A statistically significant association was observed between coated implants and untreated implants. Conclusion The application of gold nanoparticles and aqueous extract of apricot kernels appears to be promising in reducing inflammation and improving bone apposition on the titanium implant surface. However, this preliminary investigation warrants further research.

Antibody response of endangered riparian brush rabbits to vaccination against rabbit hemorrhagic disease virus 2.

Rabbit hemorrhagic disease virus 2 (RHDV2; Caliciviridae, Lagovirus europaeus), the cause of a highly transmissible and fatal lagomorph disease, has spread rapidly through the western United States and Mexico, resulting in substantial mortality in domestic and wild rabbits. The disease was first detected in California in May 2020, prompting an interagency/zoo/academia/nonprofit team to implement emergency conservation actions to protect endangered riparian brush rabbits (Sylvilagus bachmani riparius) from RHDV2. Prior to vaccinating wild rabbits, we conducted a vaccine safety trial by giving a single SC dose of Filavac VHD K C+V (Filavie) vaccine to 19 adult wild riparian brush rabbits captured and temporarily held in captivity. Rabbits were monitored for adverse effects, and serum was collected before vaccination, and at 7-10, 14-20, and 60 d post-vaccination. Sera were tested using an ELISA to determine antibody response and timing of seroconversion. Reverse-transcription quantitative real-time PCR (RT-qPCR) was performed on rectal swabs to evaluate infection status. No adverse effects from the vaccine were observed. Before vaccination, 18 of 19 rabbits were seronegative, and RHDV2 was not detected by RT-qPCR on any rectal swabs. After vaccination, all rabbits developed an antibody response, with titers of 1:10-1:160. Seroconversion generally occurred at 7-10 d. The duration of antibody response was ≥60 d in 12 of 13 rabbits. Sixteen animals were released and 4 were recaptured several months later, offering a glimpse into longer duration immune response. Our study has informed vaccination strategies for this species and serves as a model for protecting other vulnerable lagomorphs against RHDV2.

Diffusion- and Perfusion-Weighted Imaging to Detect Neurological Deficits in Acute Focal Cerebral Ischemia in Rabbits.

To investigate the relationship of diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI) parameters with dysfunction in acute focal cerebral ischemia (ACI) rabbits. The model of ACI in the middle cerebral artery was made using 30 adult male New Zealand rabbits. The dysfunction severities of the ACI rabbits were assessed using Purdy's score. A paired-sample rank sum test was adopted to compare the abnormal signal zone (ASZ) volumes from T2 weighted imaging (T2WI), dynamic susceptibility contrast-enhanced (DSC) imaging, and DWI with a relative cerebral blood flow (rCBF) map; correlations were analyzed between the volume of each ASZ and Purdy's score by Spearman's rank correlation coefficient. The degree of necrotic and apoptotic cells was evaluated in the ASZ from DWI and DSC PWI-DWI mismatch (PDM) zone. Correlations were analyzed between the index of cellular damage and Purdy's score, the volume of ASZs by Spearman's rank correlation coefficient. The ASZ volumes from DSC-PWI and the rCBF maps were larger than those from DWI (p < 0.001 and p < 0.001, respectively); those from the rCBF map (Z = 0.959, p < 0.001) and DSC-PWI (Z = 0.970, p < 0.001) were positively correlated with DWI; a positive correlation was found between Purdy's score and the ASZ volumes from DSC-PWI (Z = 0.889, p < 0.001), DWI (Z = 0.921, p < 0.001), and rCBF (Z = 0.891, p < 0.001). A significant difference was observed between the ASZ from DWI and the PDM zone in terms of the degree of necrotic (p < 0.001) and apoptotic cells (p < 0.001). The degree of cellular damage in the ASZ of DWI and PDM zone had no relationship with Purdy's score and the volumes of ASZs. The ASZ volumes from DSC-PWI, rCBF, and particularly DWI reflected the level of dysfunction in rabbits with ACI.

Impact of acute stress disorder on surfactant protein D levels in acute lung injury.

Many people sustain acute lung injuries in road traffic collisions, but few studies have dealt with such injuries in live models. This study aimed to explore the basic pathophysiological and inflammatory changes in adult rabbits following acute thoracic trauma. We randomly assigned 50 rabbits to control and injury groups. Rabbits in the injury group were subjected to right chest pressure (2600g) using a Hopkinson bar. Measurements were taken in the control group and 0, 24, 48, and 72h after injury in the injury group. Injury severity was evaluated in gross view; with haematoxylin and eosin (H&E) staining; and through the serum changes of tumor necrosis factor alpha (TNF-α), surfactant protein D (SP-D), and neutrophils. Secretion changes in SP-D in right lung injured tissues were estimated by western blotting and qPCR. Serum TNF-α levels increased rapidly immediately after injury, gradually recovering after 24, 48, and 72h (p < 0.01). The percentage of neutrophils in the accompanying blood showed a consistent trend. Gross necropsy and H&E staining indicated different levels of bleeding, alveoli exudation, and inflammatory transformation after impact. ELISA depicted the same trend in circulation (F = 22.902, p < 0.01). Western blotting showed that SP-D protein levels in tissues decreased at 0h and increased at 24, 48, and 72h. We demonstrate the feasibility of a model of impact lung injury. Primary impact caused injury without external signs. Inflammation began immediately, and the lungs began recovering at 24, 48, and 72h, as shown by increased SP-D levels in circulation and tissues.With complaints of ALI and inflammation, SP-D may be a potential biomarker after chest trauma.

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.

Impact of Freeze-dried Corticocancellous Bone Allograft Combined with Enamel Matrix Derivative in the Treatment of Critical-sized Calvarial Bone Defects: An Animal Study.

This study compared the quality and quantity of newly formed bone in rabbits' critical-sized calvarial defects filled with enamel matrix derivative (EMD) combined with freeze-dried bone allograft (FDBA) vs FDBA alone. A total of 24 adult male white New Zealand rabbits were included. In each rabbit, three bone defects with a diameter of 8 mm were created on the calvarium bone; the first defect was left untreated, while the second was filled with FDBA, and the third was filled with EMD + FDBA. Twelve rabbits were randomly euthanized after a month, and the remaining 2 month postsurgery. Bone sections were histologically evaluated by hematoxylin and eosin and vascular endothelial growth factor (VEGF), alkaline phosphatase (ALP), osteoprotegerin (OPG), and receptor activator of NF-kappaB (RANK) immune-histochemical staining. An improvement in the newly formed bone percentage was found in the defects filled with EMD + FDBA in comparison with FDBA and control defects at 1 month and 2 months postsurgery. Additionally, the expression of VEGF, ALP, OPG, and RANK showed highly significant differences in the defects filled with EMD + FDBA compared to the FDBA and control ones at 1 month postsurgery (p = 0.001). Meanwhile, VEGF and ALP expression showed a significant decrease in defects filled with EMD + FDBA compared to the FDBA and control ones (p = 0.001), while OPG and RANK expression showed non-significant differences between treated groups at 2 months postsurgery. Enamel matrix derivative combined with FDBA has a synergistic effect on bone formation and graft substitution. This combination accelerates the expression of VEGF, ALP, OPG, and RANK. The combination of EMD and FDBA accelerates and ameliorates the quality of newly formed bone, aiding in maxillofacial reconstruction. How to cite this article: Zakri RN, Grawish ME, Mowafey B, et al. Impact of Freeze-dried Corticocancellous Bone Allograft Combined with Enamel Matrix Derivative in the Treatment of Critical-sized Calvarial Bone Defects: An Animal Study. J Contemp Dent Pract 2024;25(5):424-431.

Integrating myocardial metabolic imaging and stress myocardial contrast echocardiography to improve the diagnosis of coronary microvascular diseases in rabbits.

Persistent challenges associated with misdiagnosis and underdiagnosis of coronary microvascular disease (CMVD) necessitate the exploration of noninvasive imaging techniques to enhance diagnostic accuracy. Therefore, we aimed to integrate multimodal imaging approaches to achieve a higher diagnostic rate for CMVD using high-quality myocardial metabolism imaging (MMI) and myocardial contrast echocardiography (MCE). This combination diagnostic strategy may help address the urgent need for improved CMVD diagnosis. In this study, we established five distinct pretreatment groups, each consisting of nine male rabbit: a fasted group, a nonfasted group, a sugar load group, an acipimox group, and a combination group of nonfasted rabbits administered insulin. Moreover, positron emission tomography-computed tomography (PET/CT) scan windows were established at 30-, 60-, and 90-minute intervals. We developed 10 CMVD models and conducted a diagnosis of CMVD through an integrated analysis of MMI and MCE, including image acquisition and processing. For each heart segment, we calculated the standardized uptake value (SUV) based on body weight (SUVbw), as well as certain ratios of SUV including SUV of the heart (SUVheart) to that of the liver (SUVliver) and SUVheart to SUV of the lung (SUVlung). Additionally, we obtained three coronary SUVbw uptake values. To clarify the relationship between SUVbw uptake values and echocardiographic parameters of the myocardial contrast agent more thoroughly, we conducted a comprehensive analysis across different pretreatment protocols. Receiver operating characteristic (ROC) curve analysis was employed to evaluate the diagnostic accuracy of each parameter in the context of CMVD. In the context of MMI, the nonfasted-plus-insulin group, as observed during the 60-minute examination, exhibited a noteworthy total 18F-fluorodeoxyglucose (18F-FDG) uptake of 47.44±6.53 g/mL, which was found to be statistically different from the other groups. To ascertain the reliability of the results, two double-blind investigators independently assessed the data and achieved a good level of agreement, according to the intraclass correlation coefficient (ICC) (0.957). The SUVbw of the nonfasted-plus-insulin group exhibited a moderate correlation with the microvascular blood flow reserve (MBFR) parameters derived from the MCE examination, as evidenced by a r value of 0.686. For the diagnosis of CMVD disease, the diagnostic accuracy of the combined diagnostic method [area under the curve (AUC) =0.789; 95% confidence interval (CI): 0.705-0.873] was significantly higher than that of the MBFR (AUC =0.697; 95% CI: 0.597-0.797) and SUVbw (AUC =0.715; 95% CI: 0.622-0.807) methods (P<0.05). Our study demonstrated the feasibility of a simple premedication approach involving free feeding and intravenous insulin in producing high-quality gated heart 18F-FDG PET/CT images in adult male New Zealand white rabbits. This technique holds considerable potential for ischemic heart disease research in rabbits and can enhance CMVD diagnosis via the comprehensive assessment of myocardial metabolism and perfusion.

The addition of mesenchymal stem cells in a bioabsorbable scaffold does not enhance tendon healing after a repair of rotator cuff tear.

The purpose of the study is to evaluate the healing potential of a full-thickness tendon defect in the rotator cuff of rabbits using a bioabsorbable scaffold impregnated with bone marrow-mesenchymal stem cells (BM-MSCs) or rotator cuff-derived mesenchymal stem cells (RC-MSCs). Sixteen adult rabbits were subjected to a full-thickness rotator cuff deficit. Rabbits were randomly assigned to four groups of four animals. In Group 0 (control), the deficit was left untreated. In Group 1, the deficit was treated with a single synthetic scaffold alone. In Group 2, the deficit was treated with the previous scaffold loaded with allogeneic BM-MSCs. In Group 3, the deficit was treated with the previous scaffold loaded with allogenic RC-MSCs. After animal sacrifice, tissue samples were subjected to histological and immunohistochemical analysis. Group 1 showed the highest mean tendon maturing score (15.3 ± 0.9) postoperatively, being significantly higher, in comparison to groups 0, 2 and 3 (p = 0.01, 0.02 and 0.01, respectively). Group 1 showed the highest mean collagen I/collagen III ratio (1.4 ± 0.8) postoperatively but without any statistical significance. The utilization of MSCs in rotator cuff repair in a rabbit model has not been associated with an enhancement in tendon healing in 16 weeks postoperatively, in comparison to controls and bioabsorbable scaffolds. The addition of MSCs does not result in better rotator cuff healing. Not applicable. This is an animal study.

Gingivo-Periosteal Expansion of Edentulous Jaw Crest with An Osmotic Self-Inflatable Expander: A Preclinical in Vivo Study.

This study examined the biocompatibility and expansion volume of tissue expanders utilizing rabbits and beagles as experimental models. The self-inflatable expander was provided using a Tissue balloon® (Neobiotech Co., Seoul, Korea). In 9 adult rabbits, a Tissue balloon® was placed under the lateral mandibular periosteum via an extraoral approach. After 2, 3, and 4 weeks (n=3), the expanders were removed, and soft tissue and bone samples were collected for analysis. Histomorphometric analysis and measurements of expander characteristics were performed. In 5 Beagles, all premolars were extracted. Three months after extraction, tissue expanders were placed in the maxilla and mandible, adjacent to dental extraction sites, and removed after 3 weeks. Gingival parameters were measured before and after expansion. Blood perfusion in the oral mucosa was assessed using a laser Doppler flowmeter at different time points. After three weeks, dogs were euthanized, and tissue samples were collected for histologic analysis, focusing on inflammatory response, bone formation, and gingival thickness changes. In the rabbit study, measurements of size, weight, and volume showed significant increases over 4 weeks. Swelling peaked at 2 weeks postimplantation and then gradually stabilized. Histologic examination revealed no signs of inflammation, and expanders were covered by collagen-rich capsules. Some bone resorption was noted due to pressure from the expanders, but the resorption was not significant. In the beagle study, twenty tissue expanders were implanted; 1 expander was lost, and 9 wounds dehisced during soft tissue healing. However, no signs of infection were noted. Histologic evaluation showed bone atrophy, attributed to swelling pressure, at the recipient site. Gingival thickness was not decreased. Perfusion measurements indicated that expansion did not affect microvascular circulation adversely. Overall, both studies suggest that tissue expanders demonstrate biocompatibility and successful expansion volume in vivo, with minimal adverse effects on surrounding tissues and microvascular circulation.

Osteoproductivity of Injectable Bone Grafts with and without Ostrich Eggshell Membrane Protein in Rabbit Femur.

The aim of this study was to evaluate the biocompatibility and effectiveness in terms of osseointegration of dental implants composed of novel injectable bone grafts with and without ostrich eggshell particles and membrane protein in rabbit femur. Sixteen adult male New Zealand rabbits were used in this study. A bone defect was created in each animal's right and left femur, and a dental implant was placed adjacent to the defect. Two graft materials were prepared, one containing the membrane protein and the other not. In two groups, the defects were filled with these materials. In the negative control group (NC, (n:8)), the defects were left empty. A commercial product of biphasic calcium sulfate was used as a positive control material (PC, n = 8). The graft groups were defined as the group with the membrane protein (MP+, (n:8)), and without the membrane protein (MP-, n:8). The animals were euthanized at the 12th week after surgery. The samples were investigated using histology, histomorphometry, and micro-computed tomography. Data were statistically analyzed using one-way ANOVA and Tukey's tests (p = 0.05). Both the PC and MP+ groups had similar newly formed bone areas, and the mean values of these groups were significantly (p < 0.05) higher than those of the MP- and NC groups. The PC group had the highest amount of unresorbed material, while the MP- group had the lowest amount of unresorbed material. The bone-implant contact (BIC) scores of the PC and MP+ groups were significantly higher (p < 0.05) than that of the NC group. The connective tissue area of the PC group was the lowest, which was significantly lower than the other groups (p < 0.05). The grafts produced are highly biocompatible and also showed osteoproductivity. Their cost-effectiveness and osteoproductive activity require further investigation.

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.

Beneficial normalization of cardiac repolarization by carnitine in transgenic short QT syndrome type 1 rabbit models.

Short QT syndrome type 1 (SQT1) is a genetic channelopathy caused by gain-of-function variants in human-ether-a-go-go (HERG) underlying the rapid delayed-rectifier K+ current (IKr), leading to QT-shortening, ventricular arrhythmias, and sudden cardiac death. Data on efficient pharmacotherapy for SQT1 are scarce. In patients with primary carnitine-deficiency, acquired-short QT syndrome (SQTS) has been observed and rescued by carnitine supplementation. Here, we assessed whether carnitine exerts direct beneficial (prolonging) effects on cardiac repolarization in genetic SQTS. Adult wild-type (WT) and transgenic SQT1 rabbits (HERG-N588K, gain of IKr) were used. In vivo electrocardiograms (ECGs), ex vivo monophasic action potentials (APs) in Langendorff-perfused hearts, and cellular ventricular APs and ion currents were assessed at baseline and during L-Carnitine/C16-Carnitine-perfusion. Two-dimensional computer simulations were performed to assess re-entry-based ventricular tachycardia-inducibility. L-Carnitine/C16-Carnitine prolonged QT-intervals in WT and SQT1, leading to QT-normalization in SQT1. Similarly, monophasic and cellular AP duration (APD) was prolonged by L-Carnitine/C16-Carnitine in WT and SQT1. As underlying mechanisms, we identified acute effects on the main repolarizing ion currents: IKr-steady, which is pathologically increased in SQT1, was reduced by L-Carnitine/C16-Carnitine and deactivation kinetics were accelerated. Moreover, L-Carnitine/C16-Carnitine decreased IKs-steady and IK1. In silico modelling identified IKr changes as the main factor for L-Carnitine/C16-Carnitine-induced APD-prolongation. 2D simulations revealed increased sustained re-entry-based arrhythmia formation in SQT1 compared to WT, which was decreased to the WT-level when adding carnitine-induced ion current changes. L-Carnitine/C16-Carnitine prolong/normalize QT and whole-heart/cellular APD in SQT1 rabbits. These beneficial effects are mediated by acute effects on IKr. L-Carnitine may serve as a potential future QT-normalizing, anti-arrhythmic therapy in SQT1.

In vivo and in vitro efficacy of the ithmid kohl/zinc-oxide nanoparticles, ithmid kohl/Aloe vera, and zinc-oxide nanoparticles/Aloe vera for the treatment of bacterial endophthalmitis

The aim of this study was to investigate the efficacy of the ithmid kohl/zinc-oxide nanoparticles (ZnONPs), ithmid kohl/Aloe vera, and ZnONPs/Aloe vera in the treatment of bacterial endophthalmitis. The endophthalmitis model was prepared by contaminating both eyes of 24 healthy adult male albino rabbits with a clinical isolate of Klebsiella pneumoniae. The animals were randomly divided into eight groups (A-H) according to the treatment. Group A received 1 ml of ithmid kohl/ZnONPs ointment, group B received 1 ml of ithmid kohl/Aloe vera gel ointment, group C received 1 ml of ZnONPs/Aloe vera gel ointment, and groups D, E, and F were treated with 1 ml of ithmid kohl solution (0.5 g/ml in distilled water), 1 ml of ZnONPs (0.5 g/ml) colloidal dispersion, and 1 ml of Aloe vera gel, respectively. Group G received 100 μl of a tetracycline antibiotic solution (final concentration: 16 µg/ml), and group H received sterile distilled water (no treatment). In vitro antibacterial activity was evaluated against K. pneumoniae using the agar well diffusion. The combination of ithmid kohl/ZnONPs was the most effective formulation for treating endophthalmitis model in infected rabbits within 2 days. In vitro antibacterial assay confirmed the potential of the ithmid kohl/ZnONPs formulation, which had the largest zone of inhibition (31 mm) among the compounds tested. The preparation of the ithmid kohl/ZnONPs formulation and its in vivo experiment in albino rabbits for the treatment of bacterial endophthalmitis was an innovative approach that has shown promise and may potentially serve as a viable alternative in clinical practice.

Effect of Mesenchymal Stem Cells-Derived Exosomes on Healing of a Rabbit Model of Corneal Alkali Burn. Histological and Immunohistochemical Study

Abstract Introduction Corneal alkali burn is one of the most severe ophthalmic emergencies that requires prompt treatment. Recently, the attention of researchers has been attracted to the use of exosomes as a novel non-cell therapy for treatment of corneal alkali burn. Aim to evaluate the possible role of mesenchymal stem cells (MSCs)-derived exosomes on healing of experimentally induced corneal alkali burn in rabbits by histological and immunohistochemical techniques. Materials and Methods Forty-five adult male New Zealand white rabbits were divided into three groups: group I (control group); group II in which corneal alkali burn was left for spontaneous healing, and group III (exosomes treated group): in which rabbits received a sub-conjunctival injection of 100 μg MSCs-exosomes after one hour from corneal alkali burn induction. Injection of exosomes was repeated every other day. All groups were further subdivided into two subgroups; subgroup A and B, where corneal specimens were collected after 7 days and 14 days, respectively. Characterization of exosomes was done using transmission electron microscope. Gross examination of the cornea was done at days 0, 1, 4,7,10 and 14. At the end of experiment, corneal specimens were collected and subjected to hematoxylin and eosin, Masson`s trichrome, periodic acid Schiff, transforming growth factor-beta and vascular endothelial growth factor immunohistochemical techniques. Histo-morphometric study and statistical analysis were also done. Results Administration of MSCs-derived exosomes in group III improved healing of corneal alkali burn by inhibiting angiogenesis and inflammation, enhancing corneal reepithelization, and providing better organization of newly formed stromal collagen fibers. Conclusion Sub-conjunctival injection of MSCs-derived exosomes could be effective in the healing of corneal alkali burn in adult rabbits.

Effects of Different Scleral Photo-Crosslinking Modalities on Scleral Stiffness and Hydration.

The purpose of this study was to evaluate the biomechanical and hydration differences in scleral tissue after two modalities of collagen cross-linking. Scleral tissue from 40 adult white rabbit eyes was crosslinked by application of 0.1% Rose Bengal solution followed by 80 J/cm2 green light irradiation (RGX) or by application of 0.1% riboflavin solution followed by 5.4 J/cm2 ultraviolet A irradiation (UVX). Posterior scleral strips were excised from treated and untreated sclera for tensile and hydration-tensile tests. For tensile tests, the strips were subjected to uniaxial extension after excision. For hydration-tensile tests, the strips were dehydrated, rehydrated, and then tested. Young's modulus at 8% strain and swelling rate were estimated. ANOVAs were used to test treated-induced differences in scleral biomechanical and hydration properties. Photo-crosslinked sclera tissue was stiffer (Young's modulus at 8% strain: 10.7 ± 4.5 MPa, on average across treatments) than untreated scleral tissue (7.1 ± 4.0 MPa). Scleral stiffness increased 132% after RGX and 90% after UVX compared to untreated sclera. Scleral swelling rate was reduced by 11% after RGX and by 13% after UVX. The stiffness of the treated sclera was also associated with the tissue hydration level. The lower the swelling, the higher the Young's modulus of RGX (-3.8% swelling/MPa) and UVX (-3.5% swelling/MPa) treated sclera. Cross-linking with RGX and UVX impacted the stiffness and hydration of rabbit posterior sclera. The Rose Bengal with green light irradiation may be an alternative method to determine the efficacy and suitability of inducing scleral tissue stiffening in the treatment of myopia.

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.

Establishment of a Rabbit Model of Adjacent Intervertebral Disk Degeneration After Lumbar Fusion and Fixation and Evaluation of Autophagy Factor Expression in Nucleus Pulposus Cells.

The objectives of this research were to establish an animal model of adjacent segment degeneration (ASD) bordering lumbar fusion and to investigate the expression of autophagy factors in nucleus pulposus cells of adjacent intervertebral disks. Twenty-four adult New Zealand white rabbits were enrolled and divided into two groups: group A (n=12) and group B (n=12). Posterolateral fusion and fixation were performed after intervertebral disk degeneration occurred in group A, and the rabbits were monitored for 6 months. Group B was the control group and did not undergo fusion surgery. These rabbits were monitored for 6 months. Real-time quantitative polymerase chain reaction and immunohistochemistry were performed to detect the mRNA and protein expressions of PTEN-induced kinase 1 (PINK1), Parkin, ADAMTS-4, and MMP-3. An external database, the GEO database, was used to examine the expression of these genes and analyze them for differential expression. After lumbar fusion in rabbits, the animal model of ASD exhibited gradual degeneration of adjacent intervertebral disks over time. Group A displayed significantly higher mRNA and protein expressions of PINK1 and MMP-3 but lower expression of ADAMTS-4 compared with group B (P<.05). The results analyzed in the GEO database showed that the expression of PINK1 was higher in group A than in group B, while the expression of ADAMTS-4 was lower in group A than in group B. After posterolateral lumbar fusion in rabbits, the animal ASD model showed gradual deterioration of adjacent intervertebral disks with prolonged follow-up. The findings indicate the important role of autophagy in the apoptosis of nucleus pulposus cells in adjacent intervertebral disks. [Orthopedics. 2024;47(4):e167-e173.].

Effects of graded dose of probiotics on packed cell volume, live body weight and gonadal and extragonadal sperm reserves of rabbit buck

Probiotics are live microorganisms, and when administered in sufficient amounts they grant health benefits to the host. This study was designed to determine the effects of a graded dose of probiotics on packed cell volume (PCV) live body weight and semen characteristics of the rabbit buck. Twelve healthy adult rabbit bucks were purchased and kept in the Laboratory Animal Research Unit of the Large Animal Clinic, Faculty of Veterinary Medicine, University of Maiduguri. The animals were randomly grouped into four A, B, C and D. Groups A, B and C rabbits were supplemented in their feeds with probiotics at the dose of 300 g, 200 g, and 100 g respectively. Group D, served as control and fed only a basal diet without probiotics throughout the research period. Drinking water was provided ad libitum throughout the study period. Thereafter, blood samples were collected aseptically via the ear vein once every week for six weeks and the live body weight of each rabbit in all the groups was measured with weighing balance once every week for six weeks. At the end of the six weeks, the rabbit bucks were aseptically prepared for orchidectomy and their testes were used for evaluation of gonadal and extragonadal sperm reserves. The results reveal that the (PCV) and the live body weight were significant (P ˂ 0.05) among the treated groups when compared to the control (group D). However, the Gonadal morphometric gonadal and extragonadal sperm reserves were not significant (p ˃ 0.05) among the treated groups when compared to the control (group D). In conclusion, Probiotics have the potential and influence on the (PCV) and live body weight of the rabbits in a dose-dependent manner, with no significant effects on the semen characteristics of the rabbits bucks.

Effects of graded dose of probiotics on packed cell volume, live body weight and gonadal and extragonadal sperm reserves of rabbit buck

Probiotics are live microorganisms, and when administered in sufficient amounts they grant health benefits to the host. This study was designed to determine the effects of a graded dose of probiotics on packed cell volume (PCV) live body weight and semen characteristics of the rabbit buck. Twelve healthy adult rabbit bucks were purchased and kept in the Laboratory Animal Research Unit of the Large Animal Clinic, Faculty of Veterinary Medicine, University of Maiduguri. The animals were randomly grouped into four A, B, C and D. Groups A, B and C rabbits were supplemented in their feeds with probiotics at the dose of 300 g, 200 g, and 100 g respectively. Group D, served as control and fed only a basal diet without probiotics throughout the research period. Drinking water was provided ad libitum throughout the study period. Thereafter, blood samples were collected aseptically via the ear vein once every week for six weeks and the live body weight of each rabbit in all the groups was measured with weighing balance once every week for six weeks. At the end of the six weeks, the rabbit bucks were aseptically prepared for orchidectomy and their testes were used for evaluation of gonadal and extragonadal sperm reserves. The results reveal that the (PCV) and the live body weight were significant (P ˂ 0.05) among the treated groups when compared to the control (group D). However, the Gonadal morphometric gonadal and extragonadal sperm reserves were not significant (p ˃ 0.05) among the treated groups when compared to the control (group D). In conclusion, Probiotics have the potential and influence on the (PCV) and live body weight of the rabbits in a dose-dependent manner, with no significant effects on the semen characteristics of the rabbits bucks.