Rodent ventilator

In order to assess MBG levels in a mouse model of post-myocardial infarction heart failure, left anterior descending (LAD) artery ligation was performed in C57BL6J mice and plasma MBG was assayed after 4 weeks. Briefly, mice were intubated and ventilated with 60% oxygen at 120 breaths per minute with an inspiratory pressure of 16 to 18 cm H₂O using a rodent ventilator (Harvard Apparatus). After sternotomy was performed, the left atrium was retracted for visualization of the proximal LAD using a surgical microscope (Leica M500) and the LAD was ligated with 10-0 prolene suture. Blanching and dysfunction of the anterior wall verified LAD ligation. To directly test for a potential contribution of MBG to promotion of cardiac dysfunction and nitrative stress, osmotic minipumps (Alzet® model 1004) were placed intraperitoneally in order to deliver MBG (0.1 ug/g/day) or vehicle to mice for 4 weeks similar to what we have reported in the rat^{22 (link)}. Quantitative real-time PCR was used to measure gene expression with 18S rRNA used as the internal control (TaqMan®, Life Technologies). These studies were approved by the Cleveland Clinic Institutional Animal Care and Use Committee and the procedures followed were in accordance with institutional guidelines.

Cerebrovascular reactivity was assessed as previously described.^{9 (link)} Briefly, mice were anesthetized with isoflurane and a 4-mm right parietal cranial window was made. After 15 hours’ recovery, mice were re-anesthetized and ventilated with a rodent ventilator (Harvard Apparatus, Holliston, MA). Core body temperature was maintained at 37±0.1°C by a thermo-regulated heating pad. Arterial blood pressure and gases were assessed via femoral catheterization. Leptomeningeal arterioles were visualized using Nikon Eclipse ME600 microscope (Nikon Instruments Inc., Melville, NY) and MetaMorph Image Analysis (Molecular Devices, Sunnyvale, CA). The endothelium-dependent vasodilator acetylcholine (ACh; 100 μM) and the endothelium-independent vasodilator S-nitroso-N-acetyl-penicillamine (SNAP; 500 μM) were infused, followed by artificial CSF until baseline vessel diameter returned. Vessel diameters were quantified via Diamtrak (Tim Neild, Monash University, Melbourne, Australia).