Forsøksdyr: Angiotensin II treatment and C5aR1 inhibition in C3 knock-out, CD14 knock-out, C3CD14 double knock-out mice and the effects on the heart


Godkjenningsdato 28.05.2018

Purpose: Recently we found indications that a part of the complement system can be activated without following the traditionally know complement activation pathway. This so called C3-independent C5a generation is probably mediated through thrombin. Since angiotensin II has been shown to be thrombogenic this indicateds that there is thrombin generation in mice we infused with angiotensin II. Mice are infused with angiotensin II to create a well known hypertension model.

Expected distress for the animals,:
The mice will undergo non invasive blood pressure measurement (mild), non invasive echocardiography (mild), insertion of osmotic mini pumps (moderate) and daily i.p. injections(mild), and blood samples (mild) will be obtained. Mice will be monitored closely after the pump insertion regarding pain/discomfort, especially during the first hours.

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 heart failure and might uncover potential treatment effects in this process.

Number of mice for the total application (4 years): 576 mice, consisting of 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 heart failure 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, 12213). As a result; we can make a better prediction on the number of mice who are needed for this experiment. Furthermore, we have refined the methods for the usage of heart tissue after sacrifice and we can use the same heart for histology, RNA and protein analysis.

Refinement:
The mice are handled by the same, trained researchers, assuming to reduce stress. We will follow well established methods regarding osmotic mini pump surgery, 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.