Japanese White Rabbits Research Articles

Maxillary sinus floor augmentation using sponge- and cotton-like graft materials in a rabbit model

ObjectivesBone graft materials commonly used for maxillary sinus floor augmentation (MSFA), including hydroxyapatite (HAp) and β-tricalcium phosphate (β-TCP), are mostly granular and have poor handleability. HAp/collagen composite material (HAp/Col) and β-tricalcium phosphate (β-TCP)/poly(L-lactide-co-glycolide) (PLGA) have shown promise but their application in MSFA as bone graft materials remains unclear. Here, we investigated the bone-forming behavior of HAp/Col and β-TCP/PLGA in an MSFA rabbit model. MethodsMale Japanese white rabbits were used. HAP/Col or β-TCP/PLGA was randomly applied to the MSFA model. The specimens were harvested at 4 weeks (W), 8W, 16W, and 24W after surgery, and the augmented regions were evaluated using micro-computed tomography and histological analyses. ResultsThe graft materials were retained up to 16W in the HAp/Col group and 24W in the β-TCP/PLGA group. The augmented volume detected in the HAp/Col group at 4W was substantially reduced at subsequent time points. However, in the β-TCP/PLGA group, the volume observed at 4W was maintained up to 24W. In the HAp/Col group, the bone mineral content (BMC) at 4W was significantly lower than that at 8W (p=0.03716), and this elevated BMC was significantly decreased at 16W (p=0.00185) and 24W (p=0.00236). In the β-TCP/PLGA group, the BMC tended to increase from 4W to 16W and then decreased. ConclusionsBoth HAp/Col and β-TCP/PLGA are useful for MSFA because of their ability to form new bone and good handleability. The appropriate graft material should be selected depending on the application needs while understanding the properties of the newly formed bone.

Mechanism research of elastic fixation promoting fracture healing based on proteomics and fracture microenvironment.

This study aimed to demonstrate the promoting effect of elastic fixation on fracture, and further explore its mechanism at the gene and protein expression levels. A closed tibial fracture model was established using 12 male Japanese white rabbits, and divided into elastic and stiff fixation groups based on different fixation methods. Two weeks after the operation, a radiograph and pathological examination of callus tissue were used to evaluate fracture healing. Then, the differentially expressed proteins (DEPs) were examined in the callus using proteomics. Finally, in vitro cell experiments were conducted to investigate hub proteins involved in this process. Mean callus volume was larger in the elastic fixation group (1,755 mm3 (standard error of the mean (SEM) 297)) than in the stiff fixation group (258 mm3 (SEM 65)). Pathological observation found that the expression levels of osterix (OSX), collagen, type I, alpha 1 (COL1α1), and alkaline phosphatase (ALP) in the callus of the elastic fixation group were higher than those of the stiff fixation group. The protein sequence of the callus revealed 199 DEPs, 124 of which were highly expressed in the elastic fixation group. In the in vitro study, it was observed that a stress of 200 g led to upregulation of thrombospondin 1 (THBS1) and osteoglycin (OGN) expression in bone marrow mesenchymal stem cells (BMSCs). Additionally, these genes were found to be upregulated during the osteogenic differentiation process of the BMSCs. Elastic fixation can promote fracture healing and osteoblast differentiation in callus, and the ability of elastic fixation to promote osteogenic differentiation of BMSCs may be achieved by upregulating genes such as THBS1 and OGN.

The electrophysiological effects of Tongyang Huoxue granules on the ignition phase during hypoxia/reoxygenation injury in sinoatrial node cells.

This study was undertaken to explore the potential therapeutic effects of Tongyang Huoxue Granules (TYHX) on sinoatrial node (SAN) dysfunction, a cardiac disorder characterized by impaired impulse generation or conduction. The research question addressed whether TYHX could positively influence SAN ion channel function, specifically targeting the sodium-calcium exchanger (I NCX) and L-type calcium channel (I CaL) of the SAN. Sinoatrial node cells (SANCs) were isolated and cultured from neonatal Japanese big-eared white rabbits within 24h of birth. The study encompassed five groups: Control, H/R (hypoxia/reoxygenation), H/R+100μg/mL TYHX, H/R+200μg/mL TYHX, and H/R+400μg/mL TYHX. The H/R model, simulating hypoxia/reoxygenation stress, was induced within 5days of culture. Whole-cell patch clamp technique was employed to record currents following a 3-min perfusion and stabilization period with TYHX. TYHX administration demonstrated improvements in the ignition phase of impaired SANCs. The half-maximal effective dose of TYHX, as determined by SANC beating frequency, was found to be 323.63μg/mL. Inward current density of I NCX increased in response to TYHX (200 and 400μg/mL), while TYHX enhanced I CaL current density in H/R SANCs, with 400μg/mL exhibiting greater efficacy. Additionally, TYHX regulated the gating mechanisms of I CaL by right-shifting the steady-state inactivation curve and accelerating recovery from inactivation. Notably, TYHX increased the activation time constant under 200 and 400μg/mL, prolonged the fast inactivation time constant τ1 with 400μg/mL, and extended the slow inactivation time constant τ2 with 100 and 400μg/mL. The findings suggest that TYHX may hold promise as a therapeutic intervention for sinus node dysfunction, offering potential avenues for drug development aimed at safeguarding SAN function.

Comparative study on the establishment efficacy of four types of animal models of rectovaginal fistula in rabbits

Various surgical methods have so far been developed for treating rectovaginal fistula (RVF), each with its own advantages and disadvantages. The lack of standardized animal models of RVF is a major reason for the failure to establish a unified and effective surgical method for the treatment of RVF. This study aimed to explore the feasibility of an RVF animal model by magnetic compression and compare it with the traditional modeling method. Thirty-two female Japanese white rabbits were randomly divided into four groups: A, B, C, and D, based on how the rectovaginal septum was treated. The operation time, intraoperative blood loss, and model success rate of each group were determined. The experimental animals were euthanized 2 weeks after the operation. Their rectovaginal septum specimens were obtained. RVF was observed by the naked eye. The fistula size was measured. Histological changes of fistula were observed by hematoxylin and eosin and Masson staining. All rabbits completed the RVF model and survived 2 weeks after the operation. Groups A and B had no bleeding, while groups C and D had < 0.5 mL of bleeding. The magnet detached in 4–6 days in group A, while it remained in place for 2 weeks after surgery in group B. Only one group D rabbit had a plastic hose for 2 weeks after surgery. The RVFs of groups A and C healed by themselves. In group B, the fistula was well formed. In group D, fistula healing was observed in three animals and the diameter of the fistulas was only 2.82–4.64 mm in the other four animals. Groups B and D had a scar on the inner surface of fistulas. Our study shows that the magnetic compression technique based on the T-shaped magnet is a highly useful method to establishing a continuous and stable RVF model in rabbits.

Mandibular Endochondral Growth Is Specifically Augmented by Nutritional Supplementation with Myo-Inositol Even in Rabbits.

Mandibular retrognathism occurs by insufficient mandibular growth and causes several issues, such as respiratory difficulty and diminished masticatory function. At present, functional orthodontic appliances are used for stimulating mandibular growth in pediatric cases. However, the effectiveness of functional appliances is not always stable in daily practices. A more effective, reliable, and safer therapeutic method for mandibular growth promotion would be helpful for growing mandibular retrognathism patients. As we previously discovered that nutritional supplementation of myo-inositol in growing mice specifically increases mandibular endochondral growth, we performed preclinical animal experiments in rabbits in this study. Briefly, six-week-old male Japanese white rabbits were fed with or without myo-inositol supplementation in laboratory chow until 25 weeks old, and 3D image analysis using micro CT data and histological examinations was done. Myo-inositol had no systemic effect, such as femur length, though myo-inositol specifically augmented the mandibular growth. Myo-inositol increased the thickness of mandibular condylar cartilage. We discovered that the nutritional supplementation of myo-inositol during the growth period specifically augmented mandibular growth without any systemic influence, even in rabbits. Our results suggest the possibility of clinical use of myo-inositol for augmentation of the mandibular growth in growing mandibular retrognathism patients in the future.

Femtosecond Laser Irradiation to Zirconia Prior to Calcium Phosphate Coating Enhances Osteointegration of Zirconia in Rabbits.

Calcium phosphate (CaP) coating of zirconia and zirconia-based implants is challenging, due to their chemical instability and susceptibility to thermal and mechanical impacts. A 3 mol% yttrium-stabilized tetragonal zirconia polycrystal was subjected to femtosecond laser (FsL) irradiation to form micro- and submicron surface architectures, prior to CaP coating using pulsed laser deposition (PLD) and low-temperature solution processing. Untreated zirconia, CaP-coated zirconia, and FsL-irradiated and CaP-coated zirconia were implanted in proximal tibial metaphyses of male Japanese white rabbits for four weeks. Radiographical analysis, push-out test, alizarin red staining, and histomorphometric analysis demonstrated a much improved bone-bonding ability of FsL-irradiated and CaP-coated zirconia over CaP-coated zirconia without FsL irradiation and untreated zirconia. The failure strength of the FsL-irradiated and CaP-coated zirconia in the push-out test was 6.2-13.1-times higher than that of the CaP-coated zirconia without FsL irradiation and untreated zirconia. Moreover, the adhesion strength between the bone and FsL-irradiated and CaP-coated zirconia was as high as that inducing host bone fracture in the push-out tests. The increased bone-bonding ability was attributed to the micro-/submicron surface architectures that enhanced osteoblastic differentiation and mechanical interlocking, leading to improved osteointegration. FsL irradiation followed by CaP coating could be useful for improving the osteointegration of cement-less zirconia-based joints and zirconia dental implants.

Increased serum levels of high-mobility group box 1 protein and the location characteristics in the patients of intracranial aneurysms

ObjectiveInflammation-related factors play a crucial role in intracranial aneurysms (IA) initiation, progression, and rupture. High mobility group box 1 (HMGB-1) serves as an alarm to drive the pathogenesis of the inflammatory disease. This study aimed to evaluate the role of HMGB-1 in IA and explore the correlation with other inflammatory-related factors. MethodsA total of twenty-eight adult male Japanese white rabbits were included in with elastase-induced aneurysms, n = 18) and the control group (normal rabbits, n = 10). To assess the expression of HMGB-1, both reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA) was performed on serum samples obtained from human subjects (10 patients with IA and 10 healthy donors) as well as from rabbits (aneurysm group and control group). Immunohistochemistry and immunofluorescence were employed to evaluate the expression levels of elastic fibers, HMGB-1, tumor necrosis factor-alpha (TNF-α), and triggering receptor expressed on myeloid cells-1 (TREM-1). ResultsThe expression of HMGB-1 was found to be significantly higher in the IA group compared to the control group, both at the mRNA and protein levels (P < 0.0001). Similar findings were observed in the rabbit aneurysm model group compared to the control group (P < 0.0001). HMGB-1 expression was observed to be more abundant in the inner wall of the aneurysm compared to the external wall, whereas in the control group, it was rarely scattered. Additionally, the localization patterns of TNF-α and TREM-1 exhibited similar characteristics to HMGB-1. ConclusionOur findings demonstrate that HMGB-1 is highly expressed in both IA patients and rabbit aneurysm models. Furthermore, the similar localization patterns of HMGB-1, TNF-α, and TREM-1 suggest their potential involvement in the inflammatory processes associated with IA. These results highlight the potential of HMGB-1 as a novel therapeutic target for IA.

The Responses of Arterial Stiffness Parameter Beta-Derived Index of the Aorta and Illiac-Femoral Artery to Acute Hypovolemia in Rabbits

Introduction: Acute hemorrhage decreases blood pressure (BP) and sometimes causes hypovolemic shock. At this time, peripheral arteries are supposed to contract and increase peripheral vascular resistance to raise BP. However, there has not been an adequate index of a degree of arterial stiffness. We assessed changes in arterial stiffness during rapid bleeding using new BP-independent vascular indices, aBeta and ifBeta, determined by applying the cardio-ankle vascular index theory to the elastic (aorta) and muscular (common iliac-femoral) arteries, respectively, in rabbits. Methods: Eleven Japanese white male rabbits were fixed at the supine position under pentobarbital anesthesia. Fifteen percent of the total blood volume was depleted at a rate of 2 mL/kg/min for 6 min; 15 min later, the withdrawn blood was re-transfused at the same rate. Pressure waves at the origin of the aorta (oA), distal end of the abdominal aorta (dA), distal end of the left common iliac artery (fA), and flow waves at oA were measured simultaneously. Beta was calculated using the following formula: beta = 2ρ/PP × ln(SBP/DBP) × PWV2, where ρ, SBP, DBP, and PP are blood density, systolic, diastolic, and pulse pressures, respectively. aBeta, ifBeta, and aortic-iliac-femoral beta (aifBeta) were calculated using aPWV, ifPWV, and aifPWV, respectively. Results: BP declined significantly at oA, dA, and fA during the acute bleeding. aBeta and aifBeta increased significantly from 3.7 and 5.0 before the bleeding (control) to 5.0 (about 34%) and 6.3 (about 26%) on average, while ifBeta decreased significantly from 20.5 before the bleeding to 17.1 (about 17%) after the completion of the bleeding. Reverse reactions of those indices were observed by transfusing the removed blood. Conclusion: Total arterial stiffness (aifBeta) increased; however, the elastic and muscular arteries stiffened and softened during the bleeding, respectively. These results would give useful diagnostic information during fall in BP.

Histological differences in cartilage layer growth at various tendon and ligament insertions in rabbits.

Objectives: Histological differences in cartilage layer growth in Achilles tendon (AT), quadriceps tendon (QT), patellar tendon (PT), and anterior cruciate ligament (ACL) insertion are unclear. Therefore, this study aimed to investigate the differences in cartilage layer growth in AT, QT, PT, and ACL insertions. Materials and Methods: Forty-eight male Japanese white rabbits were used. Six animals were euthanized at different stages (day 1 and 1, 2, 4, 6, 8, 12, and 24 weeks). Safranin O-stained glycosaminoglycan (GAG) production area, chondrocyte count, and insertion width were investigated. Results: A two-way analysis of variance (ANOVA) revealed a significant difference in the main effects of time and insertion for all parameters. In addition, the time × insertion interaction was significant. Multiple comparisons showed a significant difference between the ACL insertion and all other variables; however, the GAG production area was not significantly different for the QT, PT, and AT insertions. AT insertions were significantly different from all other groups; however, the number of chondrocytes and insertion width were not significantly different for ACL, QT, and PT insertions. Conclusion: Cartilage layer growth differed between the AT, QT, PT, and ACL insertions. The differences between the insertions may also be due to the differences in their structures, locations, and mechanical environments.

Rabbits as Animal Models for Anti-Tick Vaccine Development: A Global Scenario.

Studies evaluating candidate tick-derived proteins as anti-tick vaccines in natural hosts have been limited due to high costs. To overcome this problem, animal models are used in immunization tests. The aim of this article was to review the use of rabbits as an experimental model for the evaluation of tick-derived proteins as vaccines. A total of 57 tick proteins were tested for their immunogenic potential using rabbits as models for vaccination. The most commonly used rabbit breeds were New Zealand (73.8%), Japanese white (19%), Californians (4.8%) and Flemish lop-eared (2.4%) rabbits. Anti-tick vaccines efficacy resulted in up to 99.9%. Haemaphysalis longicornis (17.9%) and Ornithodoros moubata (12.8%) were the most common tick models in vaccination trials. Experiments with rabbits have revealed that some proteins (CoAQP, OeAQP, OeAQP1, Bm86, GST-Hl, 64TRP, serpins and voraxin) can induce immune responses against various tick species. In addition, in some cases it was possible to determine that the vaccine efficacy in rabbits was similar to that of experiments performed on natural hosts (e.g., Bm86, IrFER2, RmFER2, serpins and serine protease inhibitor). In conclusion, results showed that prior to performing anti-tick vaccination trials using natural hosts, rabbits can be used as suitable experimental models for these studies.

Droperidol lowers the shivering threshold in rabbits.

Perioperative shivering is common and can occur as a result of hypothermia or changes in the threshold of thermoregulation. Droperidol usage for anesthesia is currently limited to its sedative and antiemetic effects. We investigated the effects of high and low doses of droperidol on the shivering threshold in rabbits. Forty-two male Japanese white rabbits were anesthetized with isoflurane and randomly assigned to the control, high-dose, or low-dose group. Rabbits in the high-dose group received a 5mg/kg droperidol bolus followed by continuous infusion at 5mg/kg/h, those in the low-dose group received a 0.5mg/kg droperidol bolus, and those in the control group received the same volume of saline as the high-dose group. Body temperature was reduced at a rate of 2-3°C/h, and the shivering threshold was defined as the subject's core temperature (°C) at the onset of shivering. The shivering thresholds in the control, high-dose, and low-dose groups were 38.1°C ± 1.1°C, 36.7°C ± 1.2°C, and 36.9°C ± 1.0°C, respectively. The shivering thresholds were significantly lower in the high-dose and low-dose groups than in the control group (P < 0.01). The thresholds were comparable between the high-dose and low-dose groups. Droperidol in high and low doses effectively reduced the shivering threshold in rabbits. Droperidol has been used in low doses as an antiemetic. Low doses of droperidol can reduce the incidence of shivering perioperatively and during the induction of therapeutic hypothermia.

Pharmacological effects and mechanism of Kaihoujian Throat Spray (children's type) in the treatment of pediatric acute pharyngitis and tonsillitis

ContextKaihoujian Throat Spray children's type (KHJSC) is a Chinese medicine prescription for treating pediatric acute pharyngitis and tonsillitis (APT). However, its relevant mechanisms remain unclear. ObjectiveTo investigate the pharmacological effects of KHJSC on APT in vitro and in vivo, and explore the possible mechanism and target proteins. Materials and methodsThe antiviral and antibacterial effects in vitro were evaluated by IC50 and MICs. Thirty-six Japanese white rabbits were averagely divided into control group, model group, amoxicillin group and 3 dose groups of KHJSC (720, 540 and 360 μL/kg/d). The model rabbits were injected with β-hemolytic Streptococcus solution into the tonsils for 2 consecutive days. KHJSC treatment started on the third day. The whole blood, serum, tonsil tissues and pharyngeal mucosa tissues were collected for routine blood tests, proteomic, ELISA and other tests on the sixth day. ResultsThe IC50 of KHJSC on HCoV-229E, influenza PR8 and Ad3 were 1.99, 1.99 and 4.49 mg/mL, respectively; MICs of MDR-PA, MRSA and β-hemolytic Streptococcus were 350, 350, and 175 mg/mL. KHJSC markedly decreased the number of white blood cells, lymphocytes, neutrophils, and the level of IL-1β, IL-5, IL-6, IL-18, TNF-α and MCP-1; increased the content of IL-2 and IFN-γ. Proteomic analysis and ELISA revealed that PI3K-Akt signaling pathway, NF-κB signaling pathway and Toll-like receptor signaling pathway were the potential mechanisms of KHJSC against APT. Discussion and conclusionThese results provided the reference and scientific basis for the application of KHJSC in clinic and further mechanisms study.

Novel oviduct endoscope combining optical coherence tomography with intratubal ultrasonography for fallopian tube exploration: An in vivo rabbit pilot study

Background and study aimCurrently, several limitations exist in the examination of the oviduct. In this study, the usefulness and feasibility of a novel ultrafine dual-modality oviduct endoscopy device for in vivo assessment of the oviduct were evaluated. MethodsFive Japanese white rabbits were selected to undergo oviduct probing using a combination of optical coherence tomography (OCT) and intratubal ultrasonography. The feasibility of the procedure was evaluated through 152 pairs of clear, clinically interpretable images obtained using spiral scanning via the pull-back method. OCT images were compared with the oviduct histopathology sections. ResultsVisualization of the oviduct using both OCT and ultrasound revealed a differentiated three-layer tissue; however, ultrasound showed a poorer clarity than OCT. By comparing OCT images with the histological morphology of the oviduct, the inner low-reflective layer of the oviduct corresponds to the mucosal layer, the middle high-reflective layer corresponds to the fibrous muscle layer, and the outer low-reflective layer corresponds to the connective tissue layer. Postoperatively, the general condition of the animals was good. ConclusionThis study demonstrated the feasibility and potential clinical value of the novel ultrafine dual-modality oviduct endoscope. Dual-modality imaging of OCT and intratubal ultrasonography can provide clearer microstructure of the oviduct wall.

Low Replication Efficiency of a Japanese Rabbit Hepatitis E Virus Strain in the Human Hepatocarcinoma Cell Line PLC/PRF/5.

A Japanese rabbit hepatitis E virus (HEV) strain, JP-59, has been identified in a feral rabbit. When this virus was transmitted to a Japanese white rabbit, it caused persistent HEV infection. The JP-59 strain shares an <87.5% nucleotide sequence identity with other rabbit HEV strains. Herein, to isolate JP-59 by cell culture, we used a 10% stool suspension recovered from a JP-59-infected Japanese white rabbit and contained 1.1 × 107 copies/mL of the viral RNA and using it to infect a human hepatocarcinoma cell line, PLC/PRF/5. No sign of virus replication was observed. Although long-term virus replication was observed in PLC/PRF/5 cells inoculated with the concentrated and purified JP-59 containing a high titer of viral RNA (5.1 × 108 copies/mL), the viral RNA of JP-59c that was recovered from the cell culture supernatants was <7.1 × 104 copies/mL during the experiment. The JP-59c strain did not infect PLC/PRF/5 cells, but its intravenous inoculation caused persistent infection in rabbits. The nucleotide sequence analyses of the virus genomes demonstrated that a total of 18 nucleotide changes accompanying three amino acid mutations occurred in the strain JP-59c compared to the original strain JP-59. These results indicate that a high viral RNA titer was required for JP-59 to infect PLC/PRF/5 cells, but its replication capability was extremely low. In addition, the ability of rabbit HEVs to multiply in PLC/PRF/5 cells varied depending on the rabbit HEV strains. The investigations of cell lines that are broadly susceptible to rabbit HEV and that allow the efficient propagation of the virus are thus needed.

Involvement of α- and β-Adrenergic Receptors in Skeletal Muscle Blood Flow Changes During Hyper-/Hypocapnia in Anesthetized Rabbits.

This study investigated the involvement of α1- and β2-adrenergic receptors in skeletal muscle blood flow changes during variations in ETCO2. Forty Japanese White rabbits anesthetized with isoflurane were randomly allocated to 1 of 5 groups: phentolamine, metaproterenol, phenylephrine, butoxamine, and atropine. Heart rate (HR), systolic blood pressure (SBP), common carotid artery blood flow (CCBF), masseter muscle tissue blood flow (MBF), and quadriceps muscle tissue blood flow (QBF) were recorded and analyzed at 3 periods: (1) baseline, (2) during hypercapnia (phentolamine and metaproterenol groups) or hypocapnia (phenylephrine, butoxamine, and atropine groups), and (3) during or after receiving vasoactive agents. MBF and QBF decreased during hypercapnia. The decrease in MBF was smaller than that in QBF. SBP and CCBF increased, while HR decreased. Both MBF and QBF recovered to their baseline levels after phentolamine administration. MBF became greater than its baseline level, while QBF did not fully recover after metaproterenol administration. MBF and QBF increased during hypocapnia. The increase rate in MBF was larger than that in QBF. HR, SBP, and CCBF did not change. Both MBF and QBF decreased to ∼90% to 95% of their baseline levels after phenylephrine or butoxamine administration. Atropine showed no effects on MBF and QBF. These results suggest the skeletal muscle blood flow changes observed during hypercapnia and hypocapnia may mainly involve α1-adrenergic but not β2-adrenergic receptor activity.

Effect of acupotomy intervention on the expressions of proteoglycans in lumbar intervertebral disc of rabbits with lumbar intervertebral disc degeneration

To observe the effect of acupotomy intervention on the expressions of biglycan(BGN), decorin(DCN) and Caspase-3 in lumbar intervertebral disc of rabbits with lumbar intervertebral disc degeneration (LIDD), so as to explore its possible mechanism in relieving LIDD. Thirty male Japanese white rabbits were randomly divided into normal, model and acupotomy groups, with 10 rabbits in each group. The LIDD model was established by axial compression method, and magnetic resonance imaging (MRI) was used to judge whether the model was successful or not. After modeling, the acupotomy was applied to lumbar (L)4-L5 spinous process space and bilateral transverse processes for loosening, twice a week for 4 weeks. The structural changes of L4-L5 intervertebral disc were observed by MRI. The morphological changes of lumbar spine were observed by HE staining. The expression of Caspase-3 in nucleus pulposus was observed by immunohistochemistry, and the protein expressions of DCN and BGN in intervertebral disc were detected by Western blot, separatively. After mode-ling, the rabbits showed slow movement, stiff back muscles with cords or nodules, the fibrous ring structure of lumbar intervertebral disc was disordered, the number of nucleus pulposus cells was reduced, and the signal intensity of L4-L5 intervertebral disc was decreased in the model group relevant to the normal group. At the same time, the expression of Caspase-3 in nucleus pulposus was increased significantly (P<0.05), and the expression levels of DCN and BGN in intervertebral disc were decreased significantly (P<0.05). After acupotomy treatment, the modeling induced slow movement, stiff back muscles and disordered structure of lumbar intervertebral disc were significantly improved. The number of nucleus pulposus cells was increased, the signal intensity of L4-L5 intervertebral disc was enhanced, the expression of Caspase-3 in nucleus pulposus was decreased significantly (P<0.05), and the expression levels of DCN and BGN in intervertebral disc were increased significantly (P<0.05) compared with the model group. Acupotomy intervention can inhibit cell apoptosis, reduce the degradation of extracellular matrix in nucleus pulposus of intervertebral disc, and restore the normal force balance and dynamic balance of lumbar spine, which may be one of its mechanisms underlying improving LIDD.

Combination of violet light irradiation and collagenase treatments in a rabbit model of keratoconus.

We evaluated the use of collagenase treatment to generate a rabbit model of keratoconus and the impact of violet light (VL) irradiation on the disease model in six Japanese White rabbits. After epithelial debridement, the collagenase group was treated with a collagenase type II solution for 30 min; the control group was treated with a solution without collagenase. Three rabbits also underwent VL irradiation (375 nm, irradiance 310 μW/cm2) for 3 h daily for 7 days after topical collagenase application. Slit-lamp microscopy results, steep keratometry (Ks), corneal astigmatism, central corneal thickness, and axial length were examined before and after the procedure. The corneas were obtained on day 7 for biomechanical evaluation. A significant increase in Ks and corneal astigmatism was observed in the collagenase and VL irradiation groups compared with the control group on day 7. No significant difference was found in the change in corneal thickness between the groups. The elastic modulus at 3, 5, and 10% strain was significantly lower in the collagenase group than in the control group. There was no significant difference in the elastic modulus at any level of strain between the collagenase and VL irradiation groups. The average axial length at day 7 was significantly longer in the collagenase and VL irradiation groups than in the control group. Collagenase treatment induced a model of keratoconus by steepening the keratometric and astigmatic values. There was no significant difference in the observed elastic behavior of normal and ectatic corneas under physiologically relevant stress levels. VL irradiation did not cause regression of corneal steepening in a collagenase-induced model during short-term observation.

Polymerization Properties of n-Butyl Cyanoacrylate Mixed with Ethiodized Oil in the Lymphatic System: In Vivo Investigation in a Rabbit Model

PurposeTo evaluate the polymerization properties of a mixture of n-butyl cyanoacrylate (nBCA) and ethiodized oil in the lymphatic system using an animal model. Materials and MethodsNineteen male Japanese White rabbits underwent 28 lymphatic embolization procedures under fluoroscopic guidance using manually injected mixtures of nBCA and ethiodized oil at ratios of 1:2 (nBCA density of 33%), 1:4 (20%), 1:6 (14%), and 1:8 (11%) via the popliteal lymph node. The time required for polymerization and the distance traveled by the mixture were evaluated and compared among the groups using the Kruskal-Wallis test. Histopathologic intergroup comparisons and time-course changes were also evaluated using embolized lymph nodes. ResultsAmong 23 successful procedures, the mean polymerization times were 14 ± 3, 88 ± 93, 331 ± 292, and 932 seconds ± 540 and the mean distances traveled were 13 ± 10, 31 ± 44, 85 ± 89, and 108 mm ± 35 in the 33% (n = 5), 20% (n = 6), 14% (n = 6), and 11% (n = 6) groups, respectively. The 11% group demonstrated a significantly longer polymerization time than the 33%, 20%, and 14% groups and distance traveled than the 33% group. Pathologically, the embolized lymph nodes showed inflammatory changes and massive necrosis regardless of the nBCA density. ConclusionsPolymerization times and distances traveled were increased when nBCA was diluted with increasing quantitites of ethiodized oil in this rabbit model of lymphatic embolization. These relationships should be considered when dilution is prescribed for clinical use.

Antibacterial effect and biological reaction of calcium phosphate cement impregnated with iodine for use in bone defects.

Calcium phosphate cement (CPC) is often used to repair bone defects that occur after bone tumor and fracture treatment. To address bone defect cases with a high infection risk, developing CPCs with a longlasting wide-spectrum antibacterial effect is critical. Povidone-iodine has a wide antibacterial spectrum. Though there have been some reports of CPC containing antibiotics, no report of CPC with iodine has been described. In this study, the antibacterial effect and biological reaction of CPC impregnated with iodine was investigated. Iodine release from CPC and bone cement with various iodine contents (2.5, 5, and 20%) was evaluated, and 5 %-iodine CPC retained more iodine than the other CPCs after one week. Antibacterial activity against Staphylococcus aureus and Escherichia coli was also investigated, showing that 5 %-iodine had an antibacterial effect for up to eight weeks. Cytocompatibility was assessed, and 5 %-iodine CPC showed the same amount of fibroblast colony formation as control samples. CPCs with varying iodine contents (0, 5, and 20%) were then inserted into lateral femora of Japanese white rabbits for histological analysis. Osteoconductivity was evaluated using scanning electron microscopy, and hematoxylin-eosin staining. Consecutive bone formation was observed around all CPCs at eight weeks. These results indicate that CPC impregnated with iodine exhibits antimicrobial activity and cytocompatibility, and therefore, it may be effective for bone defect cases with high infection risk.

Discrimination between normal and necrotic small intestinal tissue using hyperspectral imaging and unsupervised classification.

Objective and automatic clinical discrimination of normal and necrotic sites of small intestinal tissue remains challenging. In this study, hyperspectral imaging (HSI) and unsupervised classification techniques were used to distinguish normal and necrotic sites of small intestinal tissues. Small intestinal tissue hyperspectral images of eight Japanese large-eared white rabbits were acquired using a visible near-infrared hyperspectral camera, and K-means and density peaks (DP) clustering algorithms were used to differentiate between normal and necrotic tissue. The three cases in this study showed that the average clustering purity of the DP clustering algorithm reached 92.07% when the two band combinations of 500-622 and 700-858 nm were selected. The results of this study suggest that HSI and DP clustering can assist physicians in distinguishing between normal and necrotic sites in the small intestine in vivo.