#2 The effects of NLRP3 and ASC on the heart after a permanent myocardial infarction
Introduction:
Recent studies of our group and others showed that the NLRP3/ASC complex plays a significant role in the pathogenesis after an acute MI. However, knowledge on the long-term effects are lacking. Therefore, we are studing the sub-acute to longer-term effects of the NLRP3-complex on remodeling and fibrosis in the heart up to 3 weeks after MI.
Purpose:
In FOTS applications 5926 and 6895 we have partly studied these effects and so far we found that after a myocardial infarction NLRP3 knock out mice have a better survival and an improved remodeling of the heart compared to WT and ASC-/- mice. To be able to find the mechanisms we need to carry out more detailed experiments at day 1, 5 and 21 after infarct induction.
Expected adverse effects:
The mice will undergo myocardial infarction surgery and will be monitored closely thereafter regarding pain/discomfort, especially during the acute phase (first hours/days) as sudden death due to arrhythmia or rupture of the left ventricle might occure. Adverse effects during the study will be moderate.
Expected scientific/societal benefit:
The results from this study will help us to understand more about the role the NLRP3 inflammasome plays during and after a myociardial infarction and will uncover potential treatment effects of NLRP3 and ASC in this process.
Number of mice:
450 mice, WT, NLRP3-/- and ASC-/- (all C57Bl/6J background) 1,5 and 21 days.
Replacement
We want to study the effect of the gene deletions of NLRP3 and ASC. To be able to find the mechanism behind the improved survival and remodeling in the NLRP3 knock out mice we need to study the complex relation in between cardiac remodeling, fibrosis and cardiac dysfunction after a myocardial infarction, and 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 5926, 6895). 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 infarct surgery, anaesthesia and analgesia. In addition, mice will be euthanized if body weight is reduced more than 15% of their original weight or they show signs of severe HF with inactivity and tachopnoea. Furthermore, we follow the guidelines for housing and environmental enrichment applicable to our department.
Recent studies of our group and others showed that the NLRP3/ASC complex plays a significant role in the pathogenesis after an acute MI. However, knowledge on the long-term effects are lacking. Therefore, we are studing the sub-acute to longer-term effects of the NLRP3-complex on remodeling and fibrosis in the heart up to 3 weeks after MI.
Purpose:
In FOTS applications 5926 and 6895 we have partly studied these effects and so far we found that after a myocardial infarction NLRP3 knock out mice have a better survival and an improved remodeling of the heart compared to WT and ASC-/- mice. To be able to find the mechanisms we need to carry out more detailed experiments at day 1, 5 and 21 after infarct induction.
Expected adverse effects:
The mice will undergo myocardial infarction surgery and will be monitored closely thereafter regarding pain/discomfort, especially during the acute phase (first hours/days) as sudden death due to arrhythmia or rupture of the left ventricle might occure. Adverse effects during the study will be moderate.
Expected scientific/societal benefit:
The results from this study will help us to understand more about the role the NLRP3 inflammasome plays during and after a myociardial infarction and will uncover potential treatment effects of NLRP3 and ASC in this process.
Number of mice:
450 mice, WT, NLRP3-/- and ASC-/- (all C57Bl/6J background) 1,5 and 21 days.
Replacement
We want to study the effect of the gene deletions of NLRP3 and ASC. To be able to find the mechanism behind the improved survival and remodeling in the NLRP3 knock out mice we need to study the complex relation in between cardiac remodeling, fibrosis and cardiac dysfunction after a myocardial infarction, and 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 5926, 6895). 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 infarct surgery, anaesthesia and analgesia. In addition, mice will be euthanized if body weight is reduced more than 15% of their original weight or they show signs of severe HF with inactivity and tachopnoea. Furthermore, we follow the guidelines for housing and environmental enrichment applicable to our department.