Establishment of a beagle dog model of oculomotor nerve injury

The oculomotor nerves of beagle dogs received electrical stimulation at 0.3-2.0 V. After recording compound muscle action potentials of the inferior oblique muscle, the oculomotor nerve was quickly cut off and a direct end-to-end anastomosis was then performed. As a result, the stimulating elec-trode was smoothly inserted and placed, and ideal bioelectrical signals of the interior oblique muscle were acquired. After oculomotor nerve injury, compound muscle action potentials of the inferior oblique muscle were significantly decreased in beagle dogs. These findings suggest that an animal model of oculomotor nerve injury was successfully established for electrophysiological studies.

Acute and Sub-chronic Toxicity of Indole Alkaloids Extract from Leaves of Alstonia scholaris (L.) R. Br. in Beagle Dogs

Alstonia scholaris(L.)R.Br.,an evergreen tropical plant rich in indole alkaloids with significant physiological activity,is traditionally used to treat respiratory diseases in China.This study was conducted to establish the toxicity profile of the alkaloid extract(TA)of A.scholaris leaves in non-rodents.After oral administration of a single dose(4 g/kg.bw),a num-ber of transient symptoms,such as unsteady gait,drooling,emesis,and reddening of peri-oral mucosa,were observed,but no treatment-related mortality.A sub-chronic toxicity study with a range of doses of TA(20,60 and 120 mg/kg.bw)was conducted for a 13-week treatment period,followed by 4-week recovery observation.Except for emesis and drooling in majority of animals in 120 mg/kg.bw treatment group,no clinical changes were observed in TA-treated animals.Data from electrocardiography,bone marrow,urine,fecal,hematology and clinical chemistry analyses were comparable between TA-treated and control animals.No significant differences in the relative organ weights and histopathological characteristics were evident between the TA-treated and control groups.Accordingly,the non-observed-adverse-effect-level(NOAEL)of TA was established as 120 mg/kg.bw.Our results add further knowledge to the safety database for indole alkaloid extracts from A.scholaris with potential utility as novel drug candidates.

Effectiveness of two regeneration materials in autogenous tooth transplantation in larger sockets:an experimental study in beagle dogs

Objective： To evaluate the effectiveness of regenerous tissue and bone substitute in autogenous tooth transplantation in the larger recipient socket. Methods：In 3 Beagle dogs, 18 incisors were transplanted to the recipient sockets, 2 mm wider mesio-distally. The regenerous tissue group, the bone substitute group and the control group contained 7, 7 and 4 teeth respectively. No additional material was used in control group. Clinical and radiographic examinations were done every month and were sacrificed 3 months later. Subsequently, decalcified sections were prepared for routine histological evaluation. Ordinal scores for root surface resorption were analyzed using the Kruskal-Wallis test. Results：All donor teeth survived. A statistically significant difference was found among all three treatment groups（P= 0.0001）. The proliferating tissue in space positively affected the periodontal healing without any resorption. Inflammatory resorption of the root surface and formation of new bone were observed in the bone substitute group. Surface resorptions of the roots were found in the control group. Conclusion：Proliferating tissues enhance the regeneration of periodontal tissues in larger recipient sockets and prevent root resorption. Sinbone HT is beneficial for the stabilization of the transplanted teeth in larger sockets.

Pharmacokinetic evaluation of Shenfu Injection in beagle dogs after intravenous drip administration

Shenfu Injection(SFI) is a well-defined Chinese herbal formulation that is obtained from red ginseng and processed aconite root. The main active constituents in SFI are ginsenosides and aconitum alkaloids. In this work, ginsenosides(ginsenoside Rg1, ginsenoside Rb1 and ginsenoside Rc) and aconitum alkaloids(benzoylmesaconine and fuziline) were used as the index components to explore the pharmacokinetic behavior of SFI. A selective and sensitive HPLC–MS/MS method was developed for the quantification of ginsenosides and aconitum alkaloids in dog plasma and was used to characterize the pharmacokinetics of the five index components after intravenous drip of three different dosages of SFI in beagle dogs. The pharmacokinetic properties of the index components were linear over the dose range of2–8 m L/kg.

Pharmacokinetics of propafenone hydrochloride sustained-release capsules in male beagle dogs

This paper describes the development and validation of a liquid chromatography–mass spectrometric assay for propafenone and its application to a pharmacokinetic study of propafenone administered as a new propafenone hydrochloride sustained-release capsule(SR-test), as an instant-release tablet(IR-reference) and as the market leader sustained-release capsule(Rythmol, SR-reference) in male beagle dogs(n ? 8). In Study A comparing SR-test with IR-reference in a crossover design T_(max) and t_(1/2) of propafenone for SR-test were significantly higher than those for IR-reference while C_(max) and AUC were lower demonstrating the sustained release properties of the new formulation. In Study B comparing SRtest with SR-reference the observed C_(max) and AUC of propafenone for SR-test(124.57140.0 ng/m L and612.07699.2 ng·h/m L, respectively) were higher than for SR-reference(78.52772.92 ng/m L and423.67431.6 ng·h/m L, respectively) although the differences were not significant. Overall, the new formulation has as good if not better sustained release characteristics to the market leader formulation.

Pharmacokinetic and Relative Bioavailability of Three Secoiridoid Glycosides in Beagle Dog Plasma After Oral Administration of Conventional and Enteric-Coated Capsules of Gentianella acuta Extract

Objective:To simultaneously investigate the pharmacokinetics of gentiopicroside,sweroside,and swertiamarin,which are constituents of Gentianella acuta,by developing and validating a simple,sensitive,and fast ultra-high-performance liquid chromatography–tandem mass spectrometry method.Materials and Methods:Blood samples were collected from the forward limb veins of six beagle dogs following oral gavage with G.acuta,the whole plant extract(39.90 mg/kg).Plasma samples were processed using liquid–liquid extraction.The analytes and paeoniflorin(internal standard[IS])were separated using an Acquity?UPLC ethylene bridged hybrid amide column(2.1 mm×100 mm,1.7μm)with isocratic elution using a mobile phase consisting of acetonitrile and 0.1%formic acid in water(80:20,v/v)at a flow rate of 0.4 mL/min.Quantification was performed using multiple reaction monitoring of the fragmentation transitions at m/z 401.1→179.0,403.1→195.0,419.1→179.0,and 525.2→449.1 for gentiopicroside,sweroside,swertiamarin,and the IS,respectively.Results:The linearity of the analytical response was good and the calibration curves were linear over concentration ranges of 1.20–192.0,0.40–159.0,and 0.20–209.3 ng/mL for gentiopicroside,sweroside,and swertiamarin,respectively.The extraction recovery was in the range of 84.72%–91.34%,84.58%–93.43%,and 82.75%–91.37%for gentiopicroside,sweroside,and swertiamarin,respectively.Conclusions:The method was successfully used to evaluate the pharmacokinetic parameters of gentiopicroside,sweroside,and swertiamarin in beagle dogs.

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.

Pharmacokinetic Study on Hyperoside in Beagle’s Dogs

Objective To develop and validate a simple, rapid, sensitive, and reproducible HPLC method for determination of hyperoside in plasma of dogs and for the subsequent pharmacokinetic (PK) study. Methods An accurate and reproducible HPLC-UV method was developed and validated for the determination of hyperoside in plasma of dogs, using kaempferol as internal standard. The plasma samples of dogs following ig administration of hyperoside were analyzed for the detection of quercetin after enzymatic hydrolysis treatment with combined β-glucuronidase and sulphatase. The analytes were separated on a Diamonsil C 18 column (250 mm × 4.6 mm, 5 μm). The mobile phase consisted of methanol-buffer solution (0.1 mol/L NH 4 Ac + 0.3 mmol/L EDTA-Na 2 )-acetic acid (60:40:1) and was delivered at a flow rate of 1 mL/min. The UV detector was set at 370 nm and the column temperature was maintained at 35 ℃. The sample injection volume was 20 μL. Data were collected and analyzed using the ANASTAR software. PK parameters were calculated with DAS software (2.0). Results Linear relationships were validated over the range of 0.01-1 μg/mL for hyperoside (r = 0.9997). The intra- and inter-day precision values for all samples were within 10.0%, and the accuracies of intra- and inter-day assays were within the range of 92.4%-102.4%. The validated method was successfully used to determine the hyperoside concentration in plasma of dogs for up to 12 h, after a single ig administration (25 mg/kg). The mean PK parameters for male and female dogs were as follows: C max (0.18 ± 0.05) and (0.16 ± 0.05) μg/mL, AUC 0-∞ (0.79 ± 0.34) and (0.86 ± 0.27) μg/(mL·h), t 1/2(ka) (0.89 ± 0.41) and (0.88 ± 0.28) h, respectively. Statistical analysis on the PK of hyperoside in male and female groups showed that sex had no significant impact on the PK of hyperoside (P > 0.05). Conclusion The method is able and sufficient to be used in drug PK studies of hyperoside.

Induction of intestinal metaplasia in stomach of dogs and expression of tumor-related proteins in animal gastric mucosa lesions

Objective To observe the development and progression of intestinal metaplasia (IM) in dog's stomach and expression of tumor related proteins in gastric mucosa lesions Methods IM animal model was induced in stomach of Beagle dog by combining treatment of oral administration of N methyl N' nito N nitrosoguanidine (MNNG) and ranitidine (R) with X ray irradiation to the target organ Expression of APC, p53, K ras and bcl 2 gene proteins in animal gastric mucosa lesions were determined with immunohistochemical method Results IM animal model was successfully induced and the dynamic pathological changes were observed by means of this model It was confirmed that the progression from normal epithelial cells to IM cells may require several stages, including superficial gastritis, chronic atrophic gastritis, slight focal IM and moderate or severe IM Aberrant bcl 2 protein can be detected in the atrophic mucosa epithelium and the abnormal expression of APC, K ras and bcl 2 can be found in IM of mucosa Conclusions IM model in stomach of Beagle dog can be successfully induced by our method (MNNG+R+ X ray) The progression from normal to IM in dog resembles that of human being and the expression of tumor related proteins (APC, bcl 2, K ras) may play a role in the malignant transformation of IM