Forsøksdyr: Complement and atherosclerosis


Godkjenningsdato 20.08.2018

Purpose: Recently, a novel method of inducing atherosclerosis has been described which involves administration of a viral vector encoding a dominant mutant PCSK9. The mutated PCSK9 targets liver LDLreceptors for degradation. This method makes it possible that mice of any background will become hypercholestrolemic and prone to atherosclerosis. As atherosclerosis is known to be a inflammatory disease we're aiming to investigate the effect of the complement and toll like receptor pathway, both important arms of the innate immune system, in the development of atherosclerosis by using single knock out mice for C3, CD14 and C3CD14 double knock out mice, as well as a complement C5 inhibitor.

Expected distress for the animals,:
The mice will receive a single iv injection with the virus (mild), will receive high fat diet (mild), daily ip injections with the C5 inhibitor (moderate), will undergo non invasive echocardiography (mild), and blood samples (mild) will be obtained.

Expected scientific/societal benefit:
The results from this study will help us to understand more about the specific role the complement system and toll like receptor pathway plays during the development of atherosclerosis, and might uncover potential treatment effects in this process.

Number of mice for the total application: 256 mice, consisting of males and females with the following genotypes: WT, C3 KO, CD14 KO and C3CD14 KO

Replacement:
We want to study the effect of the gene deletions of C3 and CD14, and the inhibition of C5. To be able to investigate the complex complement and toll like receptor signalling pathways in atherosclerosis development we need to study these relations in alive animals as this can not be studied by means of an in vitro experiment.

Reduction:
We have experience with this model and the phenotype of the mice (FOTS number 7783, 8395, 12213). As a result; we can make a better prediction on the number of mice who are needed for this experiment. Furthermore, to minimize the numbers of mice needed, all participants will be trained before the start of this study by the specialist in our department to assure that variation and drop out of animals are as low as possible.

Refinement:
The mice are handled by the same, trained researchers, assuming to reduce stress. We will follow well established methods regarding injection of the virus, anaesthesia and analgesia. In addition, mice will be euthanized if body weight is reduced more than 15% of their original weight or they reach other human end points. Furthermore, we follow the guidelines for housing and environmental enrichment applicable to our department.