Use of a Low-flow Digital Anesthesia System for Mice and Rats

Modified Protocol for A Mouse Heart Failure Model Using Minimally Invasive Transverse Aortic Constriction

Here, we present a modified protocol for a mouse heart failure (HF) model using minimally invasive transverse aortic constriction (miTAC). miTAC is a more effective method in mice than the standard open-chest transverse aortic constriction (TAC) to generate an HF model. miTAC does not require the cutting of the ribs or tracheal intubation with artificial ventilation; it also has a higher survival rate. The successful outcome of the HF model can be verified using transthoracic echocardiography and histology. For complete details on the use and execution of this protocol, please refer to Hu et al. (2003) and Richards et al. (2019).

Use of an Integrated Low-Flow Anesthetic Vaporizer, Ventilator, and Physiological Monitoring System for Rodents

Low-flow digital vaporizers commonly utilize a syringe pump to directly administer volatile anesthetics into a stream of carrier gas. Per animal welfare recommendations, animals are warmed and monitored during procedures requiring anesthesia. Common anesthesia and physiological monitoring equipment include gas tanks, anesthetic vaporizers and stands, warming controllers and pads, mechanical ventilators, and pulse oximeters. A computer is also necessary for data collection and to run equipment software. In smaller spaces or when performing field work, it can be challenging to configure all this equipment in limited space. The goal of this protocol is to demonstrate best practices for use of a low-flow digital vaporizer using both compressed oxygen and room air, along with an integrated mechanical ventilator, pulse oximeter, and far infrared warming as an all-inclusive anesthesia and physiological monitoring suite ideal for rodents.

A genetic mouse model of severe iron deficiency anemia reveals tissue-specific transcriptional stress responses and cardiac remodeling

Iron is a micronutrient fundamental for life. Iron homeostasis in mammals requires sustained postnatal intestinal iron absorption that maintains intracellular iron concentrations for central and systemic metabolism as well as for erythropoiesis and oxygen transport. More than 1 billion people worldwide suffer from iron deficiency anemia (IDA), a state of systemic iron insufficiency that limits the production of red blood cells and leads to tissue hypoxia and intracellular iron stress. Despite this tremendous public health concern, very few genetic models of IDA are available to study its progression. Here we developed and characterized a novel genetic mouse model of IDA. We found that tamoxifen-inducible deletion of the mammalian iron exporter ferroportin exclusively in intestinal epithelial cells leads to loss of intestinal iron absorption. Ferroportin ablation yielded a robust phenotype of progressive IDA that develops in as little as 3 months following disruption of intestinal iron absorption. We noted that, at end-stage IDA, tissue-specific transcriptional stress responses occur in which the heart shows little to no hypoxic and iron stress compared with other peripheral organs. However, morphometric and echocardiographic analysis revealed massive cardiac hypertrophy and chamber dilation, albeit with increased cardiac output at very low basal heart rates. We propose that our intestine-specific ferroportin knockout mouse model of end-stage IDA could be used in future studies to investigate IDA progression and cell-specific responses to hypoxic and iron stress.