Formation In Rabbits Research Articles

Dissolving magnesium hydroxide implants enhance mainly cancellous bone formation whereas degrading RS66 implants lead to prominent periosteal bone formation in rabbits

Bone fractures often require internal fixation using plates or screws. Normally, these devices are made of permanent metals like titanium providing necessary strength and biocompatibility. However, they can also cause long-term complications and may require removal. An interesting alternative are biocompatible degradable devices, which provide sufficient initial strength and then degrade gradually. Among other materials, biodegradable magnesium alloys have been developed for craniofacial and orthopaedic applications. Previously, we tested implants made of magnesium hydroxide and RS66, a strong and ductile ZK60-based alloy, with respect to biocompatibility and degradation behaviour. Here, we compare the effects of dissolving magnesium hydroxide and RS66 cylinders on bone regeneration and bone growth in rabbit condyles using microtomographical and histological analysis. Both magnesium hydroxide and RS66 induced a considerable osteoblastic activity leading to distinct but different spatio-temporal patterns of cancellous and periosteal bone growth. Dissolving RS66 implants induced a prominent periosteal bone formation on the medial surface of the original condyle whereas dissolving magnesium hydroxide implants enhance mainly cancellous bone formation. Especially periosteal bone formation was completed after 6 and 8 weeks, respectively. The observed bone promoting functions are in line with previous reports of magnesium stimulating cancellous and periosteal bone growth and possible underlying signalling mechanisms are discussed. Statement of significanceBiodegradable magnesium based implants are promising candidates for use in orthopedic and traumatic surgery. Although these implants are in the scientific focus for a long time, comparatively little is known about the interactions between degrading magnesium and the biological environment. In this work, we investigated the effects of two degrading cylindrical magnesium implants (MgOH2 and RS66) both on bone regeneration and on bone growth. Both MgOH2 and RS66 induce remarkable osteoblastic activities, however with different spatio-temporal patterns regarding cancellous and periosteal bone growth. We hypothesize that degradation products do not diffuse directionless away, but are transported by the restored blood flow in specific spatial patterns which is also dependent on the used surgical technique.

Effect of carboxymethyl cellulose, icodextrin and hyaluronic acid solutions on postoperative intraabdominal adhesion formation in rabbits and the role of cytokines in intraabdominal adhesion formation

In this study, the aim was to investigate the effects of 1% CMC, 4% ICO and 0.4% HA solutions in preventing postoperative IAs and their contribution to peritoneal wound healing, as well as the relationship of cytokines with the formation of postoperative IAs in rabbits. The material of the study consisted of 32 healthy rabbits. Rabbits underwent median laparotomy following general anesthesia. Serosal abraded was created at the antimesenteric border of the cecum. Next, a 3 × 2 cm peritoneum was excised on the right abdominal wall and the defect was closed using with a 2/0 silk suture. The rabbits were randomly assigned to either of the following four treatment groups: CNT (0.9% NaCl), ICO (4% icodextrin), HA (0.4% hyaluronic acid) and CMC (1% carboxymethyl cellulose). Both cecum and peritoneal surfaces were treated with 20 ml each of treatment solutions. On the 7th postoperative day, the rabbits were euthanized with a lethal dose of sodium pentobarbital and the degree of adhesion was evaluated. Samples taken from the peritoneal defect were examined histopathologically and tissue hydroxyproline levels were measured. Serum TNF-α, IL-1 and IL-6 levels were measured from blood samples taken before the surgery and at 1, 6, 24 and 48 hours after the surgery. It was observed that the adhesion grade in the HA group (p < 0.05) and CMC group (p < 0.01) was significantly lower than the control group. Although peritoneal tissue hydroxyproline levels were lower in the other groups compared to the control group, they were not statistically significant (p > 0.05). In rabbits with adhesion formation, it was determined that TNF-α levels increased at the 6th postoperative hour (p < 0.05), and IL-6 levels increased at the 6th, 24th and 48th postoperative hours (p < 0.001) compared to preoperative. In this study, treating tissues with 0.4% HA and 1% CMC solutions suppressed peritoneal inflammation, and this resulted in an increase in the levels of proinflammatory cytokines TNF-α and IL-6. It has been determined that the application of these solutions reduces postoperative adhesion formation. It was concluded that TNF-α and especially IL-6, which are proinflammatory cytokines, can be a non-invasive biomarker in determining postoperative IA formation and evaluating the adhesive process.

Qingguang'an-induced autophagy in TFs inhibits scar formation: A follow-up in vivo mechanistic investigation

PurposeTo investigate the mechanism by which Qingguang'an inhibits scar formation in rabbits administered glaucoma filtering surgery (GFS). MethodsCombined trabeculectomy was performed in 100 rabbits diagnosed with glaucoma, which were assigned to five groups, including the no surgery, surgery only, mitomycin C (MMC; positive control), Qingguang'an (experimental) and PBS (negative control) groups. The animals were followed up at postoperative days 1–28. Ultrastructure was observed under a transmission electron microscope (TEM). Real-Time Polymerase Chain Reaction (RT-PCR), Western blot, Hematoxylin and Eosin (H&E) staining, Masson's trichrome staining and Immuno-histochemistry (IHC) were performed to assess the harvested blocks. ResultsIn the Qingguang'an group, intraocular pressure (IOP) on postoperative D28 was significantly lower than values in the no surgery, surgery only and PBS groups (P < 0.05). Its blebs kept better filtering function and less complications in follow-up, which be detected to have less fibroblasts and collagen deposition histologically. Compared with the PBS group, ATG5, Beclin1 and LC3-II mRNA levels were significantly increased while P62 was downregulated in the Qingguang'an group (P < 0.05). Correspondingly, ATG5 and Beclin1 protein amounts in the Qingguang'an group were increased while P62 was downregulated. The LC3-II/Ⅰ ratio tended to rise to the process of autophagy. Abundant autophagosomes were captured under TEM in this condition. ConclusionsQingguang'an granules can inhibit scar formation in rabbits after GFS and restrain IOP increase by inducing autophagy in TFs.

Exploring the Potential of Hesperidin in Preventing Hypertrophic Scars: Insights from a Rabbit Ear Model.

Hypertrophic scars, commonly occurring after trauma or surgery in critical areas like the head and joints, pose significant challenges to both physical and mental health due to their impact on skin function and aesthetics. While the complex pathogenesis involves fibroblast activation and collagen deposition, effective treatments are lacking, underscoring the importance of exploring pathogenesis and targeted therapies. Hesperidin, a bioactive compound in citrus fruits with diverse health benefits, including anti-fibrotic and anti-angiogenic effects, is the focus of this study with the aim of investigating its impact on hypertrophic scar formation, given its potential to promote blood flow and improve skin microcirculation. This study aimed to observe the inhibitory effect of topical hesperidin on hypertrophic scars in rabbits. A total of 8 healthy adult New Zealand white rabbits were used to establish a rabbit hypertrophic scarring animal model. Five wounds were created on each rabbit's two ears, with three wounds on the left ear (groups A, B, and C) and two wounds on the right ear (groups D and E). After six days of wound drying postoperatively, the wounds were locally treated with medication as followed: group A, 0.1% hesperidin; group B, 1% hesperidin; group C, 1% triamcinolone acetonide; group D, Vaseline; and group E, blank control without any medication. After 28 days, the scar tissue samples were collected for histological examination. The results showed that the scar texture of groups B and C was softer and lighter in color, and the number of fibroblasts, capillaries, and inflammatory cells in the tissue was significantly less than those in the other three groups. The hypertrophic scar indices of groups B and C were significantly smaller than those of groups A, D, and E, and the difference was statistically significant (P < 0.05). There were no significant difference between groups B and C. Topical application of hesperidin demonstrated promising potential for reducing hypertrophic scar formation in rabbits.

Effects of Calcitonin Administration on the Amount of Bone Formation After Sutural Expansion Using Micro-CT.

Calcitonin injections were used in this investigation to see whether they influenced the quantity of bone formation after a rabbit model was subjected to micro-computed tomography expansion. Research was conducted on a total of 16 white male rabbits. Randomly, 4 groups of 4 rabbits each had their bone-borne expanders triggered by the Hyrax appliances as follows: In the first group (the control), the expansion was (0.5) mm per day for 12 days. In the second group, the same expansion protocol was used with 3 subcutaneous injections of calcitonin). In the third group, the expansion was (2.5) mm per day for 7 days followed by (0.5) mm per day for 7 days. In the fourth group, the same expansion protocol was used with 3 subcutaneous injections of calcitonin. As a result, all groups had their Hyrax devices expanded by 6mm in total. Sutural separation and new bone growth were examined by micro-computed tomography after 6 weeks of retention. To end the experiment, the rabbits were given a high dosage of phenobarbitone (90mg/kg). In the calcitonin-receiving group, there was a significant increase in anterior and posterior sutural separation, when compared with non-calcitonin-receiving groups. In the (2.5) mm instant expansion protocol, there was a significant increase in anterior and posterior sutural separation, when compared with the (0.5) mm instant expansion protocol. Calcitonin and the instant expansion protocol enhance new bone formation in rabbits.

Prolonged cyclical loading induces Haversian remodeling in mandibles of growing rabbits.

Bone adaptation to mechanical loading happens predominantly via modeling and remodeling, but the latter is poorly understood. Haversian remodeling (cortical bone replacement resulting in secondary osteons) is thought to occur in regions of low strain as part of bone maintenance or high strain in response to microdamage. However, analyses of remodeling in primates have revealed an unappreciated association with the number of daily load cycles. We tested this relationship by raising 30 male domestic rabbits (Oryctolagus cuniculus) on disparate diets from weaning to adulthood (48 weeks), facilitating a naturalistic perspective on mandibular bone adaptation. A control group consumed only rabbit pellets and an 'overuse' group ate hay in addition to pellets. To process hay, which is tougher and stiffer, rabbits increase chewing investment and duration without increasing bite force (i.e. corpus mean peak strain is similar for the two foods). Corpus remodeling in overuse rabbits was ∼1.5 times that of controls, measured as osteon population density and percentage Haversian bone. In the same subjects, there was a significant increase in overuse corpus bone formation (ratio of cortical area to cranial length), consistent with previous reports on the same dietary manipulation and bone formation in rabbits. This is the first evidence that both modeling and remodeling are simultaneously driven by the number of load cycles, independent of strain magnitude. This novel finding provides unique data on the feeding apparatus, challenges traditional thought on Haversian remodeling, and highlights the need for experimental studies of skeletal adaptation that examine mechanical factors beyond strain magnitude.

Evaluation of Two Configurations of Hydroxyapatite and Beta-Tricalcium Phosphate in Sinus Grafts with Simultaneous Implant Installation: An Experimental Study in Rabbits.

This study aimed to evaluate peri-implant bone formation in rabbits after sinus grafting mediated by hydroxyapatite and beta-tricalcium phosphate (HA + β-TCP) in granule or paste configurations, concomitant with immediate implant installation. Thirty-four rabbit maxillary sinuses were grafted with HA + β-TCP, half of which were applied in a granule and half in a paste composition. Implant placement was performed simultaneously. At 7 and 40 days postoperatively, the animals were euthanized, and samples were prepared for tomographic, microtomographic, histological, histometric (hematoxylin and eosin staining, HE), and immunohistochemical (labeling of transcription factor Runx-2 [RUNX2], vascular endothelial growth factor [VEGF], osteocalcin [OCN], and tartrate-resistant acid phosphatase [TRAP]) analysis. Implant removal torque was also measured. On tomography, maintenance of sinus membrane integrity was observed in both the groups. Higher values of morphometric parameters evaluated by micro-CT were found in the "paste group" after seven days. At 40 days, there were no significant differences between the groups in most of the microtomographic parameters evaluated. In histological sections stained with HE, a higher percentage of newly formed bone was observed in the "granule group" after 40 days. Similar positive immunolabeling was observed for both RUNX2 and OCN in both the experimental groups. TRAP immunolabeling was similar in both groups as well. VEGF labeling increased in the "granule group", indicating a higher osteoconductive potential in this biomaterial. Similar removal torque values were observed in both groups. Thus, the two HA + β-TCP configurations showed similar healing patterns of simultaneously installed implants adjacent to sinus floor elevation. However, significantly higher bone values were observed for the "granule configuration". The HA + β-TCP granules and paste presentations showed favorable long-term healing results, with bone formation in similar quantities and quality adjacent to the implants.

Histological observation on cardiogenesis during second trimester of domestic rabbit's fetuses (Oryctolagus Cuniculus)

The present work was designed to investigate the histological developmental characteristics of heart in the local rabbit fetuses. It which included the detection of timing of heart beat onset and studied morphohistogenesis of heart components. The study was performed on 35 rabbit fetuses distributed at seven groups according to the following ages: (9, 10, 12, 14, 16, 18, 20) days gestational age. The results of the current study showed that differentiation and formation of the heart began between 9th and 10th day of pregnancy in which the smooth-walled heart loop had an outer myocardial mantle, cardiac jelly and present of endocardium by histological study for serial section in each stage. The histological structures for each age showed that the heart passed through different sequential morphological stages in embryonic life represented by heart tube, looping heart, chamber formation and cardiac septation. The purpose of our study was to provide a more complete histological description of the stages of heart formation in rabbits during prenatal development.

Osteopontin (SPP1) expression on gallstone formation in rabbits fed with a lithogenic diet.

This research was designed to assess the influence of the administration of a lithogenic diet, hydrogen peroxide, and vitamin AD3E on rabbits' gallstone formation and to envisage the expression of osteopontin (OPN) in their hepatic tissues. Twenty-four healthy local mature rabbits of both genders were divided into four equal groups. At the end of the feeding period, samples of blood were taken from all rabbits after they had fasted overnight to estimate the serum lipid profile. And some of the hepatic tissue has been preserved at -28°C for molecular analysis and gene expression. The gallstones were formed 100% in the GIII and 50% in the GIV. The mRNA OPN expression showed a significant increase in the GIII when compared with other groups. In Groups III and II, the serum levels of total cholesterol, Triglyceride, L-C, low-density lipoprotein-choles, and VLDL-C were significantly increased when compared with GI, while in GIII, the serum level of high-density lipoprotein-cholesterol was significantly decreased when compared with GI. It was concluded that the expression of the mRNA OPN was increased in the hepatic tissue of gallstone-formed rabbits.

The role of systemic diseases and local conditions as risk factors.

The role of systemic diseases and local conditions as risk factors.

Развитие симптомокомплекса у кроликов при получении антисыворотки против возбудителя бактериальной почечной болезни лососевых рыб (BKD)

Bacterial kidney disease (BKD) is widespread in the world, for the first time in Russia it was revealed in 2016 by the staff of the Laboratory of Ichthyopathology of the FSC VIEV. To study the properties of the pathogen and develop diagnostic methods, an experiment was conducted on immunization of rabbits with the production of hyperimmune sera. During its implementation, the general condition of the animals was recorded, deviations of physiological indicators were noted. During the experiment, rabbits had a vivid manifestation of the symptom complex, discussed in detail in this article, and an analysis of the relationship between the manifestation of symptoms and the process of antibody formation in rabbits was carried out.

Radiographic and Histopathologic Evidences of Movement versus Immobilization Effects on Enthesis Formation in Rabbits

Enthesis joins tendon, ligament, or joint capsule to the bone, which are two very different tissues. As a result, it is more prone to stress and increased risk of rupture. The purposes of this study were to evaluate the role of limb movement or immobilization in enthesis healing after surgical repair and found out if radiography could be a reliable method for determining its prognosis. Fourteen New Zealand white rabbits were randomly divided into two groups. After detaching the Achilles tendon from the bone surface, the tendon was re-attached to the bone with a modified Kessler suture pattern. The limb of group 1 rabbits was externally fixed with the fiberglass cast. In group 2, however, no cast was used. Radiographs were taken after surgery and in weeks 2, 4, 6, and 8 post-operation. Samples were taken from the area after 8 weeks and stained by the hematoxylin-eosin method. The results were reported descriptively. Bone growth, increased chondrocytes in the cartilaginous region, and increased fibroblasts and fibrocytes were seen in group 1. While erosion, collagen fibers regularity, and tissue maturity were more predominant in group 2. Although early limb movement during the enthesis healing period helps to increase the regularity of collagen fibers in the tendinous zone of the enthesis, it does not increase the amount of callus in the bone and increases the risk of bone erosions and even fractures. While stabilizing the limb in the first two months of enthesis healing protects the bone against the forces and helps bone formation, which has a positive role in healing the enthesis.

Polypropylene mesh inhibits post-laminectomy compressive scar formation in rabbits: Histopathological and computational morphometric evaluation

We evaluated the effect of polypropylene mesh placement on post-laminectomy compressive scar formation in rabbits. Twenty-two white male New Zealand rabbits were distributed into two groups (n = 11). In the control group, the animals underwent lumbosacral laminectomy, whereas in the mesh group, the rabbits were submitted to lumbosacral laminectomy followed by the attachment of a polypropylene mesh to the vertebrae by the application of N-butyl cyanoacrylate. After eight weeks, the rabbits were euthanized, and the laminectomy area was collected for macro- and microscopic analyses. Macroscopically, we evaluated the (1) vertebral canal height; (2) laminectomy width and (3) length; and (4) fibrosis width, (5) height, and (6) length. Microscopically, we evaluated (7) fibroblasts; (8) the thickness of the dura-mater; and (9) the distance between the dura-mater and the laminectomy area. Macroscopically, there were no differences between the groups regarding vertebral canal height; width and length of the laminectomy; and fibrosis width. However, the height, and length of fibrosis were smaller in the mesh group. Microscopically, there were no differences in dura mater thickness and the distance between the dura mater and laminectomy area, but fewer fibroblasts were observed in the mesh group. This indicated that the polypropylene mesh improved tissue repair, with greater tissue organization. The results demonstrate that the use of a polypropylene mesh in the treatment of post-laminectomy wounds in rabbits reduces the severity of compressive fibrous scar formation. Polypropylene mesh is presented as a good alternative to reduce complications associated with laminectomy surgeries.

Comparison of the Effects of Acellular Dermal Matrix and Montelukast on Radiation-Induced Peri-implant Capsular Formation in Rabbits.

Capsular contracture (CC) is a troublesome complication after breast surgery with breast implants, and the risk increases in breast cancer patients after radiotherapy. Studies investigating leukotriene antagonists (eg, montelukast, zafirlukast) found that the acellular dermal matrix (ADM) can help prevent CC. We aimed to compare the effects of ADM and montelukast on CC after irradiation. Eighteen New Zealand white rabbits were randomly divided into 3 groups of 6 each. Miniature cohesive gel implants were inserted into the pocket under the latissimus dorsi muscle. The lateral part was uncovered by the latissimus dorsi muscle. Six animals were included in the control group. In experimental group A (EG-A) (n = 6), the site was partially wrapped with ADM but not covered with muscle. Montelukast (Singulair, 0.2 mg/kg) was administered in experimental group B (EG-B) (n = 6) daily. Groups were irradiated at postoperative day 21 with Co-60 γ rays (25 Gy, single fraction) at the peri-implant area. Rabbits were sacrificed 12 weeks after surgery; implants with peri-implant capsule were harvested. Capsule thickness, collagen pattern, myofibroblast, and transforming growth factor (TGF) β1/2 levels in the peri-implant capsule were evaluated. On histological evaluation, the capsule was thinner on the lateral aspect (covered with ADM) in EG-A (P = 0.004) and the entire capsule in EG-B (P = 0.004) than in the control group. However, there was no significant difference between EG-A and EG-B (P = 0.073). The collagen distribution pattern was more parallel with low density in the lateral capsular aspect in EG-A, but in the entire capsule in EG-B. The myofibroblast amount (EG-A, P = 0.031; EG-B, P = 0.016) and levels of TGF-β1 and TGF-β2 were reduced in the experimental groups (TGF-β1, EG-A, P = 0.019; TGF-β1, EG-B, P = 0.045; TGF-β2, EG-A, P = 0.018; TGF-β2, EG-B, P = 0.022). There was no significant difference between EG-A and EG-B (myofibroblast, P = 0.201; TGF-β1, P = 0.665; TGF-β2, P = 0.665). Acellular dermal matrix and montelukast have a prophylactic effect for CC even when the breast is irradiated. There was no significant difference between ADM and montelukast in preventing capsular formation. The difference is that ADM will only have the effect of covering the capsular formation with ADM and montelukast can cause systemic effects or complications.

Immunization with the Gly1127-Cys1140 amino acid sequence of the LRP1 receptor reduces atherosclerosis in rabbits. Molecular, immunohistochemical and nuclear imaging studies.

Background: The LRP1 (CR9) domain and, in particular, the sequence Gly1127-Cys1140 (P3) plays a critical role in the binding and internalization of aggregated LDL (agLDL). We aimed to evaluate whether immunization with P3 reduces high-fat diet (HFD)-induced atherosclerosis.Methods: Female New Zealand White (NZW) rabbits were immunized with a primary injection and four reminder doses (R1-R4) of IrP (irrelevant peptide) or P3 conjugated to the carrier. IrP and P3-immunized rabbits were randomly divided into a normal diet group and a HFD-fed group. Anti-P3 antibody levels were determined by ELISA. Lipoprotein profile, circulating and tissue lipids, and vascular pro-inflammatory mediators were determined using standardized methods while atherosclerosis was determined by confocal microscopy studies and non-invasive imaging (PET/CT and Doppler ultrasonography). Studies treating human macrophages (hMΦ) and coronary vascular smooth muscle cells (hcVSMC) with rabbit serums were performed to ascertain the potential impact of anti-P3 Abs on the functionality of these crucial cells.Results: P3 immunization specifically induced the production of anti-P3 antibodies (Abs) and did not alter the lipoprotein profile. HFD strongly induced cholesteryl ester (CE) accumulation in the aorta of both the control and IrP groups, and their serum dose-dependently raised the intracellular CE of hMΦ and hcVSMC, promoting TNFR1 and phospho-NF-kB (p65) overexpression. These HFD pro-inflammatory effects were dramatically decreased in the aorta of P3-immunized rabbits and in hMΦ and hcVSMC exposed to the P3 rabbit serums. Microscopy studies revealed that P3 immunization reduced the percentage of lipids, macrophages, and SMCs in the arterial intima, as well as the atherosclerotic extent and lesion area in the aorta. PET/CT and Doppler ultrasonography studies showed that the average standardized uptake value (SUVmean) of the aorta and the arterial resistance index (ARI) of the carotids were more upregulated by HFD in the control and IrP groups than the P3 group.Conclusions: P3 immunization counteracts HFD-induced fatty streak formation in rabbits. The specific blockade of the LRP1 (CR9) domain with Anti-P3 Abs dramatically reduces HFD-induced intracellular CE loading and harmful coupling to pro-inflammatory signaling in the vasculature.

Traditional Chinese patent medicine Zhixiong Capsule (ZXC) alleviated formed atherosclerotic plaque in rat thoracic artery and the mechanism investigation including blood-dissolved-component-based network pharmacology analysis and biochemical validation

Ethnopharmacological relevanceChinese patent medicine Zhixiong Capsule (ZXC) is the equal mixture of the extract of leech, Ligusticum chuanxiong Hort., Salvia miltiorrhiza Bunge, Leonurus japonicus Houtt., and Pueraria lobate (Willd.) Ohwi, which have been long used against inflammation, hyperlipidemia or blood stasis. In our previous study, ZXC showed good efficacy in preventing atherosclerosis (AS) plaque formation in rabbits. Aim of the studyIn actual clinic practice, patients are more likely to receive treatments after AS plaque formation. Therefore, the efficacy of ZXC on formed AS plaques and the underlying mechanisms were further investigated in this study. Materials and methodsSimvastatin (positive control) and ZXC (420 mg/kg and 840 mg/kg) were administrated to rats which first received long-term high fat diet administration (12 weeks). The blood lipid profiles of rats were monitored during the whole experiment, and the thoracic arteries were collected at the end of experiment for AS assessment (18th week). The blood-dissolved ZXC components were determined using an UPLC-QTOF-MS method, and the attained components were then used for network pharmacology analysis to predict the key ZXC components and targets. At last, the predicted targets were validated by ELISA and western blot methods. ResultsZXC administration showed good blood lipid-lowering effect by significantly reduced LDL-C and TC levels in rats while significantly increased HDL-C level. Compared with model group, simvastatin, low- and high-dose of ZXC administration decreased the ratio of intimal area and medial area by 81.1%, 71.1% and 71.4%, respectively (p < 0.01), and significantly alleviated collagen deposition and mineralization in rat arteries. It was found by network pharmacology analysis that leech and four components (namely daidzein, 4-methylenemiltirone, isorhamnetin and 2-isopropyl-8-methylphenanthrene-3,4-dione) are vital components for the anti-AS efficacy of ZXC. Combing the results from biochemical validation, IL-4, IL-13, MAPK1, MAPK14, JUN and P53 were confirmed as key targets of ZXC. ConclusionIt could be concluded that ZXC has value as an anti-AS agent in clinical treatment against formed AS plaque at the current application dosage.

The Effects of Autologous Platelet-Rich Plasma on the Bone Fracture Healing in Rabbits

The purpose of this study was to evaluate the effects of an autologous platelet rich-plasma on femoral fracture healing in experimentally induced rabbits’ model. In this study, 34 local breed rabbits, around 2-2.5 kg body weight, were divided into two equal groups randomly; Group A: platelet-rich plasma (PRP) and Groups B: Control group. Rabbits in both groups underwent a complete mid-shaft transverse osteotomy of the femur by a fine electrical saw. After fracture induction, the rabbits in group A (PRP group) were treated by application of 0.5 ml of autologous PRP at the site of the fractured bone, while in group B (control), rabbits were injected with distilled water. Samples from the fractured femur were collected at 10th, 20th, 30th days post operation for radiological evaluation and at 10th, 14th, 20th, and 30th days for histopathological evaluation. In radiological study, it was found that the rate of callus formation in rabbits treated with PRP (Group A) were faster than the control group (Group B) at different periods. Similarly, in histological finding it found that the stages of healing were faster in Group A when compared with Group B. It was concluded that using autologous PRP has beneficial effect to enhance the process of bone healing in the rabbit’s model.

Vitamin E Promotes Bone Formation in a Distraction Osteogenesis Model.

The long consolidation period of distraction osteogenesis (DO) may lead to complications such as pain, infection, fracture, scar formation, malunion and delayed union. The aim of this study was to evaluate the effect of systemic Vitamin E application during mandibular DO on new bone regeneration in a rabbit model. 16 adult male 8 months old New Zealand rabbits underwent mandibular lengthening with a distractor for the study. After the latency period of 5 days, the distractor was activated at a rate of 0.5 mm/12 hours for 7 days. Experimental animals received 200 mg/kg injections of α-tocopherol intraperitoneally for 7 days starting with the operation. After the consolidation period of 30 days, rabbits were sacrificed. Lengthened mandibles were obtained and subjected to dual-energy X-ray absorptiometry (DXA), radiologic and histomorphometric analysis. Statistically, bone mineral density and bone mineral content values were found to be significantly higher in the experimental group than the control group during DXA analysis. Rabbits in the experimental group had statistically higher scores in terms of osteoblast, osteoclast, vessel numbers and newly formed bone area than the control group. Results of the present study showed that systemic Vitamin E application during DO may stimulate new bone formation in rabbits and thus results in shortened treatment time.

Bone marrow concentrate-induced mesenchymal stem cell conditioned medium facilitates wound healing and prevents hypertrophic scar formation in a rabbit ear model

BackgroundHypertrophic scars (HSs) are formed via an aberrant response to the wound healing process. HSs can be cosmetic or can result in functional problems. Prolonged proliferation and remodeling phases disrupt wound healing, leading to excessive collagen production and HS formation. However, there are currently no satisfactory drugs to prevent HS formation. Mesenchymal stem cell (MSC) conditioned medium (CM) has therapeutic effects on wound healing and preventing HS formation. Bone marrow concentrate (BMC) contains various growth factors and cytokines that are crucial for regeneration and has been applied in the clinical setting. In this study, we evaluated the effects of BMC-induced MSC CM on HS formation in a rabbit ear model.MethodsWe established a rabbit ear wound model by generating full-thickness wounds in the ears of rabbits (n = 12) and treated wounds with MSC CM, BMC CM, or BMC-induced MSC CM. Dermal fibroblasts from human hypertrophic scar were stimulated with transforming growth factor beta 1 (TGF-β1) for 24 h and cultured in each culture medium for 72 h. We measured the hypertrophic scar (HS) formation during the skin regeneration by measuring the expression of several remodeling molecules and the effect of these conditioned media on active human HS fibroblasts.ResultsOur results showed that BMC-induced MSC CM had greater antifibrotic effects than MSC CM and BMC CM significantly attenuated HS formation in rabbits. BMC-induced MSC CM accelerated wound re-epithelization by increasing cell proliferation. Additionally, BMC-induced MSC CM also inhibited fibrosis by decreasing profibrotic gene and protein expression, promoting extracellular matrix turnover, inhibiting fibroblast contraction, and reversing myofibroblast activation.ConclusionsBMC-induced MSC CM modulated the proliferation and remodeling phases of wound healing, representing a potential wound healing agent and approach for preventing HS formation.

Assessment of Effects of Thyrotoxicosis on Gallstone Formation in Rabbits

Assessment of Effects of Thyrotoxicosis on Gallstone Formation in Rabbits