As far as I know, there is no way to distinguish M1 from M2 just by morphology. And I'm pretty sure that M1 and M2 are fluid, especially for the infiltrating macrophages. Tissue resident macrophages are more static, but then you are dealing with a whole other issue of lineage.

The only way I can see doing this is you need to stain one set with antibodies, and use that as a guide for the non-stained sets. But you are limited to slices that are adjacent to the stained one.

Your ideal scenario would be a transgenic mouse model where M1 and M2 macrophages are labelled with different fluorescent markers. As far as I know, unfortunately it doesn't exist. And it makes sense coz just like Shen-An Hwang said, the cell subsets are not clearly defined. There is no unique marker that identifies M1/M2 and you always need a bunch of markers to define a macrophage one way or the other. Also, depending on the environment, they may express some or all of the markers for one subset and then decide to switch to the other.

There is a transgenic mouse model where all the macrophages are GFP+ (below). I am sure there are more out there. You would still have to use antibodies if you want to look at individual subsets.

Article Human CD68 promoter GFP transgenic mice allow analysis of mo...

Thank you very much for your answers!

I was thinking at a model in which all macrophages were like gfp+ and then only the cd206+ were expressing another marker (or something similar). Ideally a transgenic mice in which a fluorescent marker was expressed under the promoter of cd206+ (or cd163 or another m2 marker).

Regards

I see what you are trying to do, but understand that the markers by themselves are not restricted to M2. And currently, remember that M2 macrophages are now even subseted themselves. I guess it "might" be possible if you are disease restricted and organ restricted and mouse strain restricted. But the validation process for this model might be more work than your availabe resources.

Good luck.

Thank you!