Angiographic investigation of orbital vascular variations in the rabbit and implications for endovascular intra-arterial chemotherapy models

BackgroundThe New Zealand White rabbit (NZWR) is the first small-animal experimental model of intra-arterial chemotherapy (IAC) for retinoblastoma treatment. The NZWR has dual ophthalmic arteries (OA): the external OA (EOA) arises from the external carotid artery and the internal OA (IOA) from the internal carotid artery. We describe the technique that we have refined for OA catheterization in rabbits, and describe the angioanatomical variations in the OA supply to the NZWR eye and implications for IAC delivery, which were identified as part of a larger project exploring IAC effects in a rabbit retinoblastoma model.MethodsWe developed techniques to perform angiography of the external and internal carotid arteries and superselective angiography of the EOA and IOA in NZWR using transfemoral access and a microwire/microcatheter system. EOA and IOA supply to the eye was determined angiographically and recorded before selective OA catheterization and angiography.Results114 rabbits underwent carotid angiographic evaluation and OA catheterization (161 total eyes evaluated, 112 right, 49 left). Most eyes had a single dominant arterial supply; either IOA or EOA. EOA was dominant in 73% (118/161), and IOA was dominant in 17% (27/161). Co-dominant supply was seen in 10% (16/161). Of the rabbits with bilateral OA catheterization, 25/47 (53%) had bilateral dominant EOA.ConclusionSuccessful catheterization of the OA in the NZWR can be readily accomplished with nuanced technique. The external OA is the dominant arterial supply in the majority of NZWR eyes. These findings allow for successful reproduction of OA catheterization studies of IAC for retinoblastoma in NZWR.

Abstract 248: Prospective Study of Ventricular Function and Survival in Acute Phase of Chagas Disease: An Animal Experimental Model

Background: Acute Cardiomyopathy secondary to Chagas disease is often subclinical when related to vector transmission. However, cases related to non-vector transmission as in patients submitted to cardiac transplant may have fatal outcomes. This study aimed to assess survival during the acute phase of Chagas disease and its relation to the ventricular function in an animal experimental model. Methods: Female Syrian hamsters (n=45) were separated in two groups: control group (CG):15 animals injected with saline solution; and infected group (IG): 30 animals inoculated with 3,5x10 4 trypomastigote forms of Trypanosoma cruzi,Y strain . Both groups were monitored daily and submitted to echocardiography with equipment dedicated to small animals (Vevo® 2100) in two different moments: baseline (before infection) and 15 days post infection. Left ventricular ejection fraction (LVEF) and global longitudinal myocardial strain (GLS) of left ventricle were measured. The IG was divided into animals with and without clinical sign (CS+) of disease: weight or fur loss, mucous wounds and lethargy. ANOVA for mixed models was used to compare the ventricular function parameters among groups over time. Survival analysis was studied using Kaplan-Meier curves and logrank test. Results: Total time follow up was 60 days. LVEF in IG was significantly reduced through time (53.80 ± 4.95 to 43.55 ± 12.10%) compared to CG (57.86 ± 7.52 to 59.73 ± 5.87%) (p=0.002). There was also a significant reduction of GLS (-18.97 ± 3.94 to -12.44 ± 4.79%) in the IG compared to CG (-19.58 ± 4.03 to -19.67 ± 4.04%) (p=0.012). Twelve animals from IG died (40.00%,12 out of 30) compared to one from CG (6.66%, 1 out of 15). Eleven out of the 12 dead animals from IG, presented, before, clinical signs (CS+). Survival was significant reduced in the IG compared to CG over time (p=0.02) (Figure 1). Conclusion: Reduced survival during the acute phase of experimental model of Chagas disease is related to the significant reduction of left ventricular function. The mortality rate in the IG is higher in the group which presents CS+.

Effect of Metronidazole on the Oxidoreductive Processes in the Submandibular and Parotid Glands in Experimental Research

Oxidative stress takes part in the pathomechanisms of many diseases, including oral disorders. The imbalance between oxidative and antioxidative processes may lead to periodontitis, osteitis, or oral cancers. Furthermore, many chemotherapeutics, e.g., metronidazole (MTZ), may also cause toxic reactions and affect oxidative reactions. The research focused on MTZ influence on oxidative destruction in the parotid and submandibular gland tissue in animal experimental model. Therefore, the concentrations of enzymatic and nonenzymatic markers of oxidative stress were measured in these two rat glands in the control and experimental MTZ-treated groups. The material for analysis included parotid and submandibular glands of male Wistar rats, which were treated with metronidazole for 7 days by gastric tube in a dose of 100 mg/kg b.w. On day 8, the material was obtained and frozen in temp. −80°C. Then, the following seven enzymatic and nonenzymatic parameters were measured: GPx, TOS, TAS, SOD, LPO, CAT, and GSH. The data were analysed using Statistica 10.0. Metronidazole treatment in the experimental model showed an increase in LPO, TOS, and TOS/TAS and a decrease in CAT, SOD, GPx, and TAS. The conclusions of this research were made. Metronidazole treatment in a dose of 100 mg/kg b.w. caused imbalance between oxidative and antioxidative reactions in the rat parotid and submandibular glands. An increase was observed in LPO, TOS, and TOS/TAS in both glands exposed to metronidazole. Decreased activity of CAT, SOD, GPx, and TAS was noted, which indicates attenuation of the gland antioxidative protective barrier.