These mice were given a non-muscle injury of LPS and harvested 24 hours after. The cells were from digested muscle and gated for live, CD45+, Ly6G- prior to the other gates. I'm not sure if these cells are a pro-inflammatory or anti-inflammatory state. It seems too early for CD206+ cells to be here.
Dear JJ,
I just briefly wanted to send you a comment on your question. From the information you gave, it's seems your macrophage phenotype looks awfully lot like the phenotype people observed in skeletal muscle of conditionally deleted IGF-1 KO mice, predating tissue regeneration. Please check the attached paper for details.
https://www.cell.com/molecular-therapy-family/molecular-therapy/fulltext/S1525-0016(16)30150-2
In addition, please bear in mind that CD206 expression (even though generally accepted as a marker for anti-inflammatory type 2 (alternatively activated) macrophages), is definitely not restricted to these cells and may be also co-expressed on pro-inflammatory macrophages after a general inflammatory stimulus like LPS injection, whereby tissue resident macrophages might be a whole different beast altogether.
Please see the attached paper, which nicely illustrates plasticity of M1/ M2 markers after LPS stimulation in vitro.
Article Novel Markers to Delineate Murine M1 and M2 Macrophages
I hope that helps at least a little!
All the best & kind regards,
Michael
Hi. Briefly too. I am one of the authors of IGF-1 KO mice and also a similar approach for the heart (see below). We are seeing CD206+ expression roughly peaking between 5-7 days after injury both in Skeletal Muscle Article Monocyte/Macrophage-derived IGF-1 Orchestrates Murine Skelet...
and Heart muscleArticle Cardiac-Restricted IGF-1Ea Overexpression Reduces the Early ...
)In addition to Michael's comments. I would like to add that we found some M0 (CD206+) in both types of muscle even before injury. Specially now due to the amazing current flow cytometry techniques we are capable of detecting tiny ammounts. That is why you should always compare it to the expected peak (in this case 5-6 days) to be sure that the amounts you detect are relevant. Ideally, you should perform a time-course like we did. Note: please also take into account the presence of infiltrating monocytes vs resident macrophage population which have a different embryological origin and expresses CD206 too. Note: It is important to distinguish between CD206 high and low.
I hope it helped, let me know if you need more clarification.
Regards
Enrique