A preliminary study of the mechanical properties of 3D-printed personalized mesh titanium alloy prostheses and repair of hemi-mandibular defect in dogs.

This study is a preliminary investigation exploring the mechanical properties of three-dimensional (3D)-printed personalized mesh titanium alloy prostheses and the feasibility of repairing hemi-mandibular defects. The ANSYS 14.0 software and selective laser melting (SLM) were used to produce personalized mesh titanium alloy scaffolds. Scaffolds printed using different parameters underwent fatigue property tests and scanning electron microscopy (SEM) of the fracture points. Models of hemi-mandibular defects (encompassing the temporomandibular joint) were created using beagle dogs. Freeze-dried allogeneic mandibles or 3D-printed personalized mesh titanium alloy prostheses were used for repair. Gross observation, computed tomography (CT), SEM, and histological examinations were used to compare the two repair methods. The prostheses with filament diameters of 0.5 and 0.7 mm could withstand 14,000 times and >600,000 cycles of alternating stresses, respectively. The truss-structure scaffold with a large aperture and large aperture ratio could withstand roughly 250,000 cycles of alternating forces. The allogeneic mandible graft required intraoperative shaping, while the 3D-printed mesh titanium alloy prostheses were personalized and did not require intraoperative shaping. The articular disc on the non-operated sides experienced degenerative changes. No liver and kidney toxicity was observed in the two groups of animals. The 3D-printed mesh titanium alloy prostheses could effectively restore the shape of the mandibular defect region and reconstruct the temporomandibular joint.

Preliminary study of a new magnetic compression technique for circumcision in dogs: An experimental animal model.

Introduction: Traditional/ritual/medical circumcision can be associated with considerable intraoperative blood loss and a prolonged postoperative healing course. This study investigated the feasibility of the magnetic compression technique (MCT) for circumcision in beagle dogs. Methods: A set of magnetic rings including a daughter magnetic ring (DMR) and a parent magnetic ring (PMR) were designed for circumcision. In eight beagle dogs as the animal model, the DMR was placed between the penis and the foreskin through the glans, and then the PMR was placed outside the penis. The DMR and PMR automatically attracted together to compress the foreskin. The necrosis of the prepuce of the anterior penis was observed daily. The operation time and time to magnetic ring shedding were recorded. Healing of the foreskin stump was visually observed. Results: The magnetic rings were successfully installed in all eight dogs, and the operation process was without complication. The average operation time was 3.13 ± 0.92 min (range, 2-4.5 min). Postoperative X-rays showed good attraction of the magnetic rings. Daily post-operative observation showed progressive ischemic necrosis of the anterior foreskin and mild edema of the proximal foreskin. The dogs were generally in good condition and urinated freely. The magnetic rings fell off spontaneously 8-12 days after the operation, and the stump of the foreskin healed well. Conclusion: The MCT may be a new approach for circumcision in a canine model, which suggests its potential for use in humans.

H3N2 canine influenza virus-like particle vaccine with great protection in beagle dogs.

In 2016, a distinct branch of H3N2 canine influenza virus (CIV) emerged, which has mutations related to mammalian adaptation and has replaced previously prevalent strains. This branch poses a risk of zoonotic infection. To prevent and control H3N2 CIV, an H3N2 virus-like particle (VLP) vaccine based on the insect cell baculovirus expression system has been developed in the study. The H3N2 VLP vaccine induced high titers of hemagglutination inhibition (HI) antibodies in nasal and muscular immunized beagle dogs. Meanwhile, the VLP vaccine provided effective protection against homologous virus challenge comparable to inactivated H3N2 canine influenza virus. In addition, the intranasal H3N2 VLP vaccine induced significantly higher Th1, Th2, and Th17 immune responses, respectively (p,0.05). Importantly, intramuscular injection of VLP and inactivated H3N2 virus has complete protective effects against homologous H3N2 virus attacks. Nasal immunization with H3N2 VLP can partially protect beagles from H3N2 influenza. IMPORTANCE: A new antigenically and genetically distinct canine influenza virus (CIV) H3N2 clade possessing mutations associated with mammalian adaptation emerged in 2016 and substituted previously circulating strains. This clade poses a risk for zoonotic infection. In our study, intramuscular injection of the H3N2 virus-like particle (VLP) vaccine and inactivated H3N2 CIV confer completely sterilizing protection against homologous H3N2 canine influenza virus challenge. Our results provide further support for the possibility of developing VLP vaccines that can reliably induce immunity in animal species.

13-Week Repeated Oral Toxicity and Toxicokinetic Studies of Rabeprazole Sodium and Sodium Bicarbonate Combination in Dogs.

The subchronic toxicity and toxicokinetics of a combination of rabeprazole sodium and sodium bicarbonate were investigated in dogs by daily oral administration for 13 consecutive weeks with a 4-week recovery period. The dose groups consisted of control (vehicles), (5 + 200), (10 + 400), and (20 + 800) mg/kg of rabeprazole sodium + sodium bicarbonate, 20 mg/kg of rabeprazole sodium only, and 800 mg/kg of sodium bicarbonate only. Esophageal ulceration accompanied by inflammation was observed in only one animal in the male (20 + 800) mg/kg rabeprazole sodium + sodium bicarbonate group. However, the severity of the ulceration was moderate, and the site of occurrence was focally extensive; thus, it was assumed to be a treatment-related effect of rabeprazole sodium + sodium bicarbonate. In the toxicokinetics component of this study, systemic exposure to rabeprazole sodium (AUClast and Cmax at Day 91) was greater in males than females, suggesting sex differences. AUClast and Cmax at Day 91 were increased compared to those on Day 1 in a dose-dependent manner. A delayed Tmax and no drug accumulation were observed after repeated dosage. In conclusion, we suggest under the conditions of this study that the no-observed-adverse-effect level (NOAEL) of the combination of rabeprazole sodium + sodium bicarbonate in male and female dogs is (10 + 400) and (20 + 800) mg/kg, respectively.

Preventing High Fat Diet-Induced Obesity and Related Hepatic Steatosis by Chlorin e6-Mediated Photodynamic Therapy.

Obesity and its associated hepatic steatosis have become a global concern, posing numerous health hazards. Photodynamic therapy (PDT) is a unique approach that promotes anti-obesity by releasing intracellular fat. Chlorin e6 (Ce6)-PDT was tested for its anti-obesity properties in male ovariectomized (OVX) beagle dogs, as well as male C57BL/6 and Balb/c mice. The 12 OVX beagles were randomly assigned to one of four groups: high-fat diet (HFD) only, Ce6 only, Ce6 + 10 min of light-emitting diode light (LED) treatment, and Ce6 + 15 min of light treatment. We assessed several parameters, such as body weight, adipose tissue morphology, serum biochemistry, and body fat content analysis by computed tomography (CT) scan in HFD-fed beagle dogs. At the end of the study period, dogs that were treated for 35 days with Ce6 and exposed to LED irradiation (660 nm) either for 10 min (Ce6 + 10 min of light) or for 15 min (Ce6 + 15 min of light) had decreased body weight, including visceral and subcutaneous fats, lower aspartate transaminase (AST)/alanine transaminase (ALT) ratios, and a reduction in the area of individual adipocytes with a concomitant increase in the number of adipocytes. Furthermore, C57BL/6 male mice following an HFD diet were effectively treated by Ce6-PDT treatment through a reduction in weight gain and fat accumulation. Meanwhile, Ce6-PDT attenuated hepatocyte steatosis by decreasing the epididymal adipose tissue and balloon degeneration in hepatocytes in HFD-fed Balb/c mice. Taken together, our results support the idea that Ce6-PDT is a promising therapeutic strategy for the recovery of obesity and obesity-related hepatic steatosis.

The stereoselective pharmacokinetics of the desmethyl-phencynonate hydrochloride in beagle dogs.

The aim of this study was to investigate the chiral inversion and the stereoselective pharmacokinetic profiles of desmethyl-phencynonate hydrochloride after administration of the single isomer and its racemate to beagle dogs. A liquid chromatography with tandem mass spectrometry (LC-MS/MS) method was established for determination of the stereoisomers on chiral columns in beagle dog plasma, which met all the requirements. The chiral inversion in dogs of the desmethyl-phencynonate hydrochloride were studied after administration of the single isomer or the racemic modification. The stereoselective pharmacokinetic profiles of the desmethyl-phencynonate hydrochloride were studied by assays for simultaneous isomers after administration of the racemic modification. The results showed that the absorption of the R-configuration dosed as the single isomer was higher than it dosed as the racemic modification. The AUC(0-t), AUC(0-∞), and Cmax of the S-configuration were much higher than those of R-configuration after oral administration of the racemic desmethyl-phencynonate hydrochloride. The chiral inversion of desmethyl-phencynonate isomers could not occur in dogs after administration of the R-configuration.

Establishment of a spontaneous ventilation anesthesia model for beagle dogs.

While spontaneous ventilation (SV) anesthesia is in use for clinical patients, there is still little systematic experimental research into its basic aspects. The rabbit SV model that we established previously has some limitations including the model being too small, differences in anesthetic drugs and anesthesia procedures, so we set out to establish an SV anesthesia model for beagle dogs.•Single lumen tracheal intubation was performed on beagles connecting a ventilator, and the anesthetic dosage was adjusted for spontaneous ventilation before surgery.•5 mL of 1 % lidocaine was applied as a local infiltration anesthesia at the surgical incision.•After thoracotomy, 5 mL of 1% lidocaine was sprayed onto the surface of the lungs and a T3-T7 intercostal nerve block (1:1 2 % lidocaine:0.75 % ropivacaine) was performed.

Herb-drug interactions of silybinin and cilofexor in beagle dogs based on pharmacokinetics by UPLC-MS/MS.

Objective: A remarkably sensitive, accurate, and efficient ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) approach was developed as a facile and expeditious method for measuring cilofexor concentration in beagle dogs, the herb-drug interactions between silybinin and cilofexor was explored based on pharmacokinetics. Methods: The plasma sample protein of the beagles were rapidly sedimented with acetonitrile, and cilofexor and tropifexor (internal standard, ISTD) were separated by gradient elution using a 0.1% formic acid aqueous solution and acetonitrile as the mobile phase. The concentrations were detected using positive ion multiple reaction monitoring (MRM) mode. Mass transfer pairs were m/z 587.91→267.91 for cilofexor and m/z 604.08→228.03 for ISTD, respectively. A two-period self-controlled experimental design was adopted for the HDIs experiment. In the first period (Group A), six beagle dogs were orally administered cilofexor at a dose of 1 mg/kg. In the second period (Group B), silybinin (3 mg/kg) was orally administered to the six beagle dogs twice a day for seven consecutive days, after which cilofexor was orally administered. The cilofexor concentration in beagle dogs was determined, and HDIs were evaluated based on their pharmacokinetics. Results: The accuracy and precision of cilofexor were both less than 15%, and the recoveries, matrix effects, and stability met the relevant requirements. The Cmax of cilofexor in group B was 49.62% higher than that in group A, whereas the AUC(0-t) and AUC(0-∞) of cilofexor in group B were 47.85% and 48.52% higher, respectively, than those in group A. Meanwhile, the t1/2 extended from 7.84 h to 9.45 h, CL and Vz decreased in Group B. Conclusion: A novel UPLC-MS/MS approach was successfully applied for the measurement of cilofexor in beagle dog plasma. Silybinin can alter the pharmacokinetics of cilofexor in beagle dogs, thereby increasing plasma exposure to cilofexor.

Toxicity and Toxicokinetics of a Four-Week Repeated Gavage of Levamisole in Male Beagle Dogs: A Good Laboratory Practice Study.

Levamisole (LVM) is considered an immunomodulatory agent that has the potential to treat various cancer and inflammation diseases. However, there is still much debate surrounding the toxicokinetic and toxicological information of LVM. Therefore, it is crucial to assess its toxicity to provide useful data for future human LVM risk assessments. In this study, a barrier environment was established under the guidance of good laboratory practice (GLP) at the Fujian Center for New Drug Safety Evaluation. Male beagle dogs were orally administered with 5, 15, and 30 mg/kg of LVM daily for four weeks. Toxicity assessment was based on various factors such as mortality, clinical signs, food and water consumption, body weight, body temperature, electrocardiogram, ophthalmological examination, hematology, serum biochemistry, organ/body coefficients, histopathological study, and toxicokinetic analysis. The results of this study showed that LVM did not exhibit any significant toxicological effects on beagle dogs at the exposure levels tested. A no observed adverse effect level (NOAEL) of LVM was set at 30 mg/kg/day for male beagle dogs, which is equivalent to a 12-fold clinical dose in humans. Moreover, the repeated exposure to LVM for four weeks did not lead to any bioaccumulation. These findings provide valuable insights for future human LVM risk assessments.

Effect and mechanical mechanism of spontaneous breathing on oxygenation and lung injury in mild or moderate animal ARDS.

OBJECTIVE: The present study aimed to determine the effect and mechanical mechanism of spontaneous breathing during mechanical ventilation on oxygenation and lung injury using Beagles dogs mild or moderate acute respiratory distress syndrome (ARDS) model. METHODS: After inducing mild or moderate ARDS by infusion of oleic acid, Eighteen Beagles dogs were randomly split into Spontaneous breathing group (BIPAPSB, n = 6), and Complete muscle paralysis group (BIPAPPC, n = 6),Six Beagles without ventilator support comprised the control group. Both groups were ventilated for 8 h under BIPAP mode. High-pressure was titrated TV to 6 ml/kg. A multi-pair esophageal balloon electrode catheter was used to measure respiratory mechanics and electromyogram. End-expiratory lung volume (EELV), gas exchange and respiratory variables were recorded in the process of mechanical ventilation. The contents of Interleukin (IL)-6 and IL-8 in lung tissue were measure using qRT-PCR. Besides, lung injury score was calculated in the end of mechanical ventilation. RESULTS: Based on the comparable setting of ventilator, BIPAPSB group exhibited higher safety peak transpulmonary pressure, abdominal pressure, EELV and P/F(PaO2/FiO2) than BIPAPPC group, whereas mean transpulmonary pressure, the mRNA levels of the IL-6 and IL-8 in the lung tissues and lung injury score in BIPAPSB group were lower than those in BIPAPPC group. CONCLUSION: In mild to moderate ARDS animal models, during mechanical ventilation, SB may improve respiratory function and reduce ventilator-induced lung injury. The mechanism may be that spontaneous inspiration up-regulates peak transpulmonary pressure and EELV; Spontaneous expiration decreases mean transpulmonary pressure by up-regulating intra-abdominal pressure, thereby reducing stress and strain.

A Novel Deformable Self-Assembled Magnetic Anastomosis Ring (DSAMAR) for Esophageal Stenosis Recanalization without Temporary Gastrostomy in Beagle Dogs.

BACKGROUND: To assess the feasibility of a deformable self-assembled magnetic anastomosis ring (DSAMAR) in the treatment of esophageal stenosis in beagle dogs via transoral access without temporary gastrostomy. METHODS: Experimental esophageal stenosis was created in 10 beagle dogs by partial cervical esophageal ligation. The DSAMAR was inserted into the distal esophagus via the narrow section of the esophagus using a gastroscope. A circular DSAMAR was placed in the proximal esophagus. The magnetic rings on both sides of the experimental stenosis automatically attracted each other. We then recorded the operation time, postoperative complications, anastomotic formation time, and magnetic ring discharge time. The dogs were euthanized 4 weeks postoperatively; subsequently, we obtained the esophageal anastomotic specimens and observed the anastomotic formation via the naked eye and by light microscopy. RESULTS: Our esophageal stenosis model produced reproducible stenoses in all dogs, which was confirmed via endoscopy and esophagography. DSAMAR was successfully implanted in all experimental animals under endoscopic and X-ray monitoring, and all linear DSAMARs were successfully transformed into rings. The magnets at both ends of the esophageal stenosis were automatically attracted. All animals survived until euthanasia. No complications, including esophageal perforation, bleeding, and gastrointestinal obstruction, were noted during the perioperative period. The mean operation time of endoscopic magnetic anastomosis was 15.6 ± 2.41 (range, 12-19) min. The mean esophageal anastomotic formation time was 8.8 ± 1.03 (range, 7-10) days, and the mean expulsion time of DSAMAR was 13.94 ± 2.88 (range, 10-19) days. Gastroscopy and esophagography were performed at 4 weeks postoperatively; the esophageal patency was good. Macroscopic observation of the esophageal anastomotic specimens revealed that the esophageal mucosal layer of the anastomosis had good continuity and the anastomosis was smooth. CONCLUSION: DSAMAR is a feasible option for magnetic recanalization of esophageal stricture via transoral access without temporary gastrostomy.

Oral treatment with the all-d-peptide RD2 enhances cognition in aged beagle dogs - A model of sporadic Alzheimer's disease.

Disease-modifying therapies to treat Alzheimer's disease (AD) are of fundamental interest for aging humans, societies, and health care systems. Predictable disease progression in transgenic AD models favors preclinical studies employing a preventive study design with an early pre-symptomatic treatment start, instead of assessing a truly curative approach with treatment starting after diagnosed disease onset. The aim of this study was to investigate the pharmacokinetic profile and efficacy of RD2 to enhance short-term memory and cognition in cognitively impaired aged Beagle dogs - a non-transgenic model of truly sporadic AD. RD2 has previously demonstrated pharmacodynamic efficacy in three different transgenic AD mouse models in three different laboratories. Here, we demonstrate that oral treatment with RD2 significantly reduced cognitive deficits in cognitively impaired aged Beagle dogs even beyond the treatment end, which suggests in combination with the treatment dependent CSF tau oligomer decrease a disease-modifying effect of RD2 treatment.

Modulation of long noncoding RNA (lncRNA) and messenger RNA (mRNA) expression in the liver of Beagle dogs by Toxocara canis infection.

BACKGROUND: Long non-coding RNAs (lncRNAs) and messenger RNAs (mRNAs) play crucial roles in regulating various physiological and pathological processes. However, the role of lncRNAs and mRNAs in mediating the liver response during Toxocara canis infection remains incompletely understood. METHODS: In the present study, the expression profile of lncRNAs and mRNAs was investigated in the liver of Beagle dogs infected by T. canis using high-throughput RNA sequencing. RESULTS: Compared with the control groups, 876 differentially expressed (DE) lncRNAs and 288 DEmRNAs were identified at 12 h post-infection (hpi), 906 DElncRNAs and 261 DEmRNAs were identified at 24 hpi, and 876 DElncRNAs and 302 DEmRNAs were identified at 36 days post-infection (dpi). A total of 16 DEmRNAs (e.g. dpp4, crp and gnas) were commonly identified at the three infection stages. Enrichment and co-localization analyses identified several pathways involved in immune and inflammatory responses during T. canis infection. Some novel DElncRNAs, such as LNC_015756, LNC_011050 and LNC_011052, were also associated with immune and inflammatory responses. Also, LNC_005105 and LNC_005401 were associated with the secretion of anti-inflammatory cytokines, which may play a role in the healing of liver pathology at the late stage of infection. CONCLUSIONS: Our data provided new insight into the regulatory roles of lncRNAs and mRNAs in the pathogenesis of T. canis and improved our understanding of the contribution of lncRNAs and mRNAs to the immune and inflammatory response of the liver during T. canis infection.

Preclinical evaluation of the effect of periodontal regeneration by carbonate apatite in a canine one-wall intrabony defect model.

Objective: This study aimed to histologically compare periodontal regeneration of one-wall intrabony defects treated with open flap debridement, ß-tricalcium phosphate (ß-TCP), and carbonate apatite (CO3Ap) in dogs. Methods: The mandibular third premolars of four beagle dogs were extracted. Twelve weeks after the extraction, a one-wall bone defect of 4 mm × 5 mm (mesio-distal width × depth) was created on the distal side of the mandibular second premolar and mesial side of the fourth premolar. Each defect was randomly allocated to open flap debridement (control group), periodontal regeneration utilizing ß-TCP, or CO3Ap. Eight weeks after the surgery, histologic and histometric analyses were performed. Results: No ankylosis, infection, or acute inflammation was observed at any of the experimental sites. Newly formed bone and cementum were observed in all experimental groups. The mineral apposition rate of the alveolar bone crest was higher in the CO3Ap group than in the control and ß-TCP groups. The ratio of the new bone area was significantly higher in the CO3Ap group than in the control group (P < 0.05). The bone contact percentage of the residual granules was significantly higher in the CO3Ap group than in the ß-TCP group (P < 0.05). Conclusion: Although this study has limitations, the findings revealed the safety and efficacy of CO3Ap for periodontal regeneration in one-wall intrabony defects in dogs, and CO3Ap has a better ability to integrate with bone than ß-TCP.

Comparison of fecal microbiota of SPF and non-SPF Beagle dogs.

Microbial colonization of animal intestine impacts host metabolism and immunity. The study was aimed to investigate the diversity of the intestinal microflora in specific pathogen free (SPF) and non-SPF Beagle dogs of different ages by direct sequencing analysis of the 16S rRNA gene. Stool samples were collected from four non-SPF and four SPF healthy Beagle dogs. From a total of 792 analyzed Operation taxonomic units, four predominant bacterial phyla were identified: Firmicutes (75.23%), Actinobacteria (10.98%), Bacteroidetes (9.33%), and Proteobacteria (4.13%). At the genus level, Streptococcus, Lactobacillus, and Bifidobacterium were dominated. Among which, Alloprevotella, Prevotella_9, and Faecalibacterium were presented exclusively in non-SPF beagles, with potentially anti-inflammatory capability, which could protect non-SPF beagles from complex microbial environment. The number and diversity of intestinal flora for non-SPF Beagle dogs were the highest at birth and gradually decreased with growth, whereas the results for the SPF beagle samples were the opposite, with the number and diversity of intestinal microbiota gradually increases as beagles grow. In a nutshell, the microbial complexity of the rearing environment can enrich the gut microbiota of beagles, many of which are anti-inflammatory microbiota with the potential to increase the adaptability of the animal to the environment. However, the gut microbiota of SPF beagles was more sensitive to environmental changes than that of non-SPF beagles. This study is of great significance for understanding the bionomics of intestinal microflora in non-SPF and SPF beagles, improving the experimental accuracy in scientific research.

Necroptosis plays a crucial role in the exacerbation of retinal injury after blunt ocular trauma.

Retinal injury after blunt ocular trauma may directly affect prognosis and lead to vision loss. To investigate the pathological changes and molecular mechanisms involved in retinal injury after blunt ocular trauma, we established a weight drop injury model of blunt ocular trauma in male Beagle dogs. Hematoxylin-eosin staining, immunofluorescence staining, western blotting, and TUNEL assays were performed to investigate retinal injury within 14 days after blunt ocular trauma. Compared with the control group, the thicknesses of the inner and outer nuclear layers, as well as the number of retinal ganglion cells, gradually decreased within 14 days after injury. The number of bipolar cells in the inner nuclear layer began to decrease 1 day after injury, while the numbers of cholinergic and amacrine cells in the inner nuclear layer did not decrease until 7 days after injury. Moreover, retinal cell necroptosis increased with time after injury; it progressed from the ganglion cell layer to the outer nuclear layer. Visual electrophysiological findings indicated that visual impairment began on the first day after injury and worsened over time. Additionally, blunt ocular trauma induced nerve regeneration and Müller glial hyperplasia; it also resulted in the recruitment of microglia to the retina and polarization of those microglia to the M1 phenotype. These findings suggest that necroptosis plays an important role in exacerbating retinal injury after blunt ocular trauma via gliosis and neuroinflammation. Such a role has important implications for the development of therapeutic strategies.

A rapid and sensitive UPLC-MS/MS method for the determination of zanubrutinib in beagle plasma and its application in pharmacokinetics.

A reliable and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed for the determination of zanubrutinib in the plasma of beagle dogs. The column used was an Acquity BEH C18 column (2.1 mm × 50 mm, 1.7 µm), maintained at 40°C with an injection volume of 2 µl. The gradient elution program was as follows: 0-1 min, 10-10% A; 1-1.1 min, 10-90% A; 1.1-2.1 min, 90-90% A; 2.1-2.2 min, 90-10% A; 2.2-3.0 min, 10-10% A. Mobile phase A was 0.1% formic acid, B was acetonitrile, and the total analysis time was 3 min. The mass spectrometry was performed in positive ion mode, and the scanning mode was multi-reaction monitoring mode with electrospray ionization as the ion source; m/z 472.2 → 455.01 for zanubrutinib and m/z 441.03 → 137.99 for ibrutinib (internal standard). The plasma samples were processed by protein precipitation. The standard curve showed good linearity (r2 = 0.999 8) in the range of 1.0-1,000 ng/ml (zanubrutinib) with a low limit of quantification of 1 ng/ml. Also, the intra-day and inter-day precision (RSD) was <5.88% and the accuracy (RE) ranged from -1.56 to 1.08%; the recoveries of zanubrutinib in beagle plasma ranged from 90.12 to 93.53% (RSD 1.67-6.42%) and the ME values of zanubrutinib were 98.70-101.06% (RSD 5.37-8.49%, n = 6). All values meet US Food and Drug Administration requirements. A rapid, highly selective and sensitive method for the determination of zanubrutinib concentration in plasma by UPLC-MS/MS was successfully developed. This method is suitable for pharmacokinetic studies in beagle dogs by following oral administration of zanubrutinib.

Development of na HPLC-MS/MS method for the determination of ginsenosides Rg1 and Rb1 from 'Shenmai' Injection in beagle dogs after single and multiple doses and application in pharmacokinetics.

Shenmai Injection (SMI), which tonifies Qi and prevents exhaustion, nourishes Yin and generates body fluid, is usually used in the treatment of shock with deficiency of Qi and Yin, coronary artery disease, viral myocarditis, granulocytopenia and chronic pulmonary heart disease clinically. Ginsenosides Rg1 and Rb1 are the main active ingredients of SMI. In this study, high-performance liquid chromatography tandem mass spectrometry methods for quantification of Rb1 and Rg1 in beagle dogs were developed and validated according to international regulatory guidelines. The methods were applied to measure the pharmacokinetics parameters of the two ginsenoside after intravenous administration. The linear ranges of the analytes were 3.9-1,000 ng/ml for Rg1 and Rb1. After injection of single and multiple doses of SMI (1 ml/kg), the plasma concentration-time profiles of Rg1 and Rb1 met the characteristics of one-compartment and typical two-compartment intravenous injection.

28-day repeated dose toxicity and toxicokinetics study on new melatonergic antidepressant GW117 in beagle dogs.

GW117 is new melatonergic antidepressant being developed to show better antidepressant action than agomelatine. The purpose of this study was to evaluate the toxicity and to determine potential target organs after oral (gavage) administration of the test article GW117 for 28 days and to assess the reversibility after a 4-week recovery phase in beagle dogs. Toxicokinetics was also evaluated. Four groups were designed in this study, including the vehicle control group and the GW117 50, 150 and 500 mg/kg/day groups, with 5 dogs/sex/group. Body weight, hematology, clinical chemistry, gross necropsy, organ weight, histopathology, and other indicators were examined. Results showed that animals dosed at ≥150 mg/kg/day showed gastrointestinal reactions (watery feces and dark green/red brown feces), with a dose-response relationship in the incidence and severity grade. Female dogs at 500 mg/kg/day had an increase in organ weight and ratios of the liver at the end of the dosing phase. Histopathology examination showed that some animals at 500 mg/kg/day, especially female animals, had minimal centrilobular hepatocyte hypertrophy in the liver, which reversed after 28-day recovery. With the exception of the above, no GW117-related abnormality was noted. Meanwhile, there were no sexual differences in drug exposure and accumulation after the first and last dosing. The no observed adverse effect dose level (NOAEL) was 150 mg/kg/day, under which mean Cmax and AUC0 → t were 583.5 and 2767.0 ng/ml*h for females and 663.2 and 4046.3 ng/ml*h for males on Day 28.

Astragalus polysaccharide (APS) supplement in beagle dogs after castration: Effects on the haematology and serum chemistry profiles, immune response, and oxidative stress status.

BACKGROUND: Castration is one of the most common surgical procedures performed in dogs. However, based on increasing evidence, male animals experience significant pain after castration. Astragalus polysaccharide (APS), one of the main bioactive components in A. membranaceus bunge, has been widely used as part of Fu-Zheng therapy to enhance natural defense mechanisms. INTRODUCTION: This study was carried out to determine the effects of supplementing different doses of Astragalus polysaccharide (APS; control, 0 mg/kg; APSL, 400 mg/kg; and APSH, 800 mg/kg) for 8 weeks on the haematology and serum chemistry profiles, immune response, and oxidative stress status in weanling beagle dogs. METHODS: After adapting to the experimental environment for 1 week, 18 male beagle dogs (Sichuan Institute of Musk Deer Breeding, China; average initial weight, 3.80 ± 0.43 g; age, 3-month-old) were randomly allotted to diets supplemented with three doses of APS (Control, 0 mg/kg; low, 400 mg/kg; and high, 800 mg/kg), referred to as control, APSL, and APSH, respectively; six dogs were assigned to each treatment. The dogs were fed the respective diets twice daily at 08:30 and 16:30 h in sufficient quantity to supply the metabolizable energy requirements for 8 weeks. On day 43 (19 weeks old), the dogs were castrated. On days 42 (prior to castration, 19 weeks old), 50 (day 7 after castration, 20 weeks old), and 57 (day 14 after castration, 21 weeks old) to measure the haematology, blood chemistry, immune response, and oxidative stress status parameters. RESULTS: Based on our findings, the APSH diet decreased weight gain and increased the feed to gain ratio in dogs (P < 0.05). At 14 days after castration, the wound was almost closed, slightly swollen, dry, and clean in the groups supplemented with APS. In addition, optimal APS supplementation was found to decrease erythrocyte count (RBC), haematocrit (HCT), alkaline phosphatase (ALP), alanine aminotransferase (ALT), C-reactive protein (CRP), interleukin 1ß (IL-1ß), and tumor necrosis factor-α (TNF-α) levels, and cortisol and protein carbonyl (PC) concentrations (P < 0.05). Moreover, the mean corpuscular haemoglobin (MCH) and platelet (PLT) levels, interleukin 10 (IL-10) and glutathione (GSH) content, and Cu/Zn superoxide dismutase (SOD1), catalase (CAT), and glutathione peroxidase (Se-GPx) activities were increased in the APS supplemented groups (P < 0.05) CONCLUSION: This study demonstrated that supplementing weanling beagle dogs with optimum APS could positively affect wound healing by improving their haematological profile (decreased RBC and HCT content, increased MCH and PLT levels), serum biochemical parameters (decreased ALP and ALT content), immune status (decreased CRP, IL-1ß, and TNF-α levels; increased IL-10 content), and antioxidant defense (decreased cortisol and PC content; increased GSH content, and SOD1, CAT, and Se-GPx activities). However, the detailed mechanism whereby APS regulates these changes requires further investigation. In addition, the results of this study suggest that 400 mg/kg diet is the optimum APS dose for beagle dogs.