The mode of anesthesia influences outcome in mouse models of arterial thrombosis

Abstract

Background Arterial thrombosis models are important for preclinical evaluation of antithrombotics but how anesthetic protocol can influence experimental results is not studied. Objectives We studied how three most commonly used rodent anesthetics affect the induction of thrombosis and thrombus resolution with antiplatelet agent integrilin (Eptifibatide). Methods The Folts, electrolytic, and FeCl 3 models of carotid artery thrombosis were evaluated. The extent of blood flow reduction required to elicit cyclic flow reductions ( CFR ) was examined in the Folts model. The occlusion time and stability following electrolytic or FeCl 3 injury was assessed. The efficacy of Eptifibatide was studied in each cohort and clot composition following FeCl 3 application was assessed histologically. Results Isoflurane and ketamine‐xylazine (ket‐x) elicited higher basal blood flow velocities. For reliable CFR in the Folts model, a higher degree of blood flow reduction was required under ket‐x and isoflurane. For the FeCl 3 and electrolytic models, injury severity had to be increased in mice under ket‐x anesthesia to achieve rapid occlusion. FeCl 3 ‐injured artery sections from ket‐x and isoflurane‐treated mice showed vessel dilatation and clots that were more fibrin/red‐cell rich compared to pentobarbitone. Integrilin led to cycle abolishment for all three Folts‐injury cohorts but for the electrolytic model a 2.5‐fold higher dose was required to restore blood flow under pentobarbitone. Integrilin after FeCl 3 arterial injury was partially ineffective in isoflurane‐treated mice. Conclusions Anesthesia impacts rodent carotid artery occlusion experiments and alters integrilin efficacy. It is important to consider anesthetic protocols in animal experiments involving pharmacological agents for treatment of atherothrombosis.

The Combination of Tissue-Engineered Blood Vessel Constructs and Parallel Flow Chamber Provides a Potential Alternative to In Vivo Drug Testing Models

“…This inhibitory effect could artefactually alter the size and structure of thrombi seen in current animal thrombosis models, potentially leading to an overestimation of the effectiveness of putative anti-platelet therapies. This is consistent with previous findings that show that the use of different anaesthetics differentially impacts the efficacy of integrin αIIbβ3 blockers in murine thrombosis models [ 39 ], thus providing initial evidence that our model system is a potential alternative to current in vivo studies. A more detailed side-by-side comparison examining the impact of different anaesthetics on the thrombotic response in current in vivo models, and in the TEBV model presented here, will be required to fully validate the model system.…”

“…In our experiments, we observed that ketamine almost completely inhibits thrombus formation upon the TEML construct. It is possible that this effect is caused by the inhibition of dense granule secretion by ketamine, as autocrine signalling molecules released from here are known to be crucial to the recruitment of circulating platelets onto the surface of forming thrombi [ 7 , 39 ]. This inhibitory effect could artefactually alter the size and structure of thrombi seen in current animal thrombosis models, potentially leading to an overestimation of the effectiveness of putative anti-platelet therapies.…”

Wall shear rates in human and mouse arteries: Standardization of hemodynamics for in vitro blood flow assays: Communication from the ISTH SSC subcommittee on biorheology

“…All data for mice were obtained in experiments performed under general anesthesia, using isoflurane, ketamine–xylazine, and pentobarbital sodium, which are known to affect the cardiorespiratory system including but not limited to peripheral perfusion, vessel diameter, and heart rate 14 . Although the effects are moderate, and do not affect general validity of the comparisons between vessels and applicability of the data to ex vivo models (the same anesthesia and young mice are typically used for in vivo thrombosis experiments, unless specific efforts are undertaken to counter this at least partially), these conditions should be noted as an important source of systemic changes for in vivo thrombosis studies 15 . Furthermore, the data provided are average values for healthy (when possible) vessels of humans and of young mice.…”

Early Endothelial Activation in a Mouse Model of Graft vs Host Disease Following Chemotherapy

“…Unlike the paper by Qiao et al, we did not see altered enzyme levels in mice receiving chemotherapy alone ( 19 ). Carstairs staining is routinely for histological detection of platelets/fibrin/collagen/red cells in thrombi ( 28 ). Automated image quantitation of the fibrin-rich areas revealed a significant increase in fibrin deposits in the BM+T cells cohort.…”

“…Histopathological changes in the liver, intestine and skin were quantified in randomly selected 20x micrographs from 3 different 5 µm sections (10 images per mouse) by a 0-3-point score by a trained pathologist blinded to experimental groups. Liver sections stained with Carstairs stain by the Monash Histology Platform; Carstairs staining was quantified as published ( 28 ).…”