[Histonet] Need help with interpretation: Gomori Trichrome / MELAS-Syndrom

[V. Neubert]

Hi all,

I'm reading about OXPHOS diseases (defects in mitochondrial protein
subunits of respiratory chain). RFF in MERRF stands for "red ragged
fibers", see:
http://en.wikipedia.org/wiki/File:Ragged_red_fibers_in_MELAS.jpg

I don't get what is stained there exactly. The picture shows a muscle
biopsy stained with Gomori's trichrome stain.. What is stained in these
red fibers?

I'm sure one of you has some experience with that.

Thanks,

V. Neubert