Angiotensin II Infusion via Osmotic Minipump
Objective: To examine the effects of angiotensin II infusion on atherosclerotic lesion severity and vascular pathology in apoE-deficient mice over a 1-month period
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Equipment1
not specified • not specified • not mentioned • not mentioned
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Protocol Steps
Osmotic minipump implantation
Implant osmotic minipumps containing either Ang II or vehicle into mature apoE-/- mice
Note: Surgical implantation procedure details not provided in text
View evidence from paper
“we infused Ang II or vehicle for 1 month via osmotic minipumps into mature apoE-/-mice”
Continuous infusion period
Allow continuous infusion of Ang II or vehicle through osmotic minipumps
Note: Infusion continues for the entire 1-month period
View evidence from paper
“we infused Ang II or vehicle for 1 month via osmotic minipumps into mature apoE-/-mice”
Measurement of arterial blood pressure
Assess whether Ang II infusion alters arterial blood pressure
Note: Results showed Ang II doses did not alter arterial blood pressure
View evidence from paper
“These doses of Ang II did not alter arterial blood pressure, body weight, serum cholesterol concentrations”
Body weight measurement
Monitor body weight changes during infusion period
Note: Ang II infusion did not alter body weight
View evidence from paper
“These doses of Ang II did not alter arterial blood pressure, body weight, serum cholesterol concentrations”
Serum cholesterol analysis
Measure serum cholesterol concentrations and lipoprotein cholesterol distribution
Note: Ang II did not alter serum cholesterol or lipoprotein distribution
View evidence from paper
“These doses of Ang II did not alter arterial blood pressure, body weight, serum cholesterol concentrations, or distribution of lipoprotein cholesterol”
Aortic atherosclerotic lesion assessment
Examine aortic tissue for atherosclerotic lesion severity and composition
Note: Lesions were predominantly lipid-laden macrophages and lymphocytes
View evidence from paper
“Ang II infusions promoted an increased severity of aortic atherosclerotic lesions. These Ang II-induced lesions were predominantly lipid-laden macrophages and lymphocytes”
Adventitial macrophage quantification
Count and analyze macrophages present in adventitial tissue underlying lesions
Note: Ang II promoted marked increase in adventitial macrophages
View evidence from paper
“Ang II promoted a marked increase in the number of macrophages present in the adventitial tissue underlying lesions”
Abdominal aortic aneurysm assessment
Examine abdominal aorta for presence and characteristics of aneurysms
Note: Pronounced abdominal aortic aneurysms were present in Ang II-infused apoE-/- mice
View evidence from paper
“pronounced abdominal aortic aneurysms were present in apoE-/-mice infused with Ang II”
Sequential sectioning of aneurysmal aorta
Perform serial sectioning of aneurysmal abdominal aorta to characterize structural features
Note: Revealed intact artery surrounded by remodeled adventitia and medial break with dilation
View evidence from paper
“Sequential sectioning of aneurysmal abdominal aorta revealed two major characteristics: an intact artery that is surrounded by a large remodeled adventitia, and a medial break with pronounced dilation”
Control experiment with apoE+/+ mice
Infuse Ang II into apoE+/+ mice to test whether hyperlipidemia is required for aneurysm formation
Note: Ang II infusions into apoE+/+ mice failed to generate aneurysms, demonstrating hyperlipidemia requirement
View evidence from paper
“infusions of Ang II into apoE+/+mice failed to generate aneurysms. The presence of hyperlipidemia was required”