As the age of adult rats increase, the ability to isolate skeletal muscle progenitor cells decrease. This can be attributed to 1) decrease in number of progenitor cells with increasing age of the animal and 2) the amount of time that is necessary for enzymatic digest increases. Check Henson et al. Histology and Histopathology, 20: 769-784, 2005. His M&M will give you all you need with resepct to supplies, protocols, etc. But you will need to increase the time for digestion dependent on age (weight) of the animals. This is related to the density of the extracellular matrix that the cells are embedded within. And I am speaking of muscle progenitor cells and not the immediate precursors of skeletal muscle, the myosatellite cells.

It is 100% sure the age affects the stem cell number and characterizes....., in skeletal muscle, the number of progenitor is drop with aging and nomovement...make is difficulty to obtain quality progenitors from aged muscle...

I think this depends somewhat on what your intentions are; do you want to isolate them and use them right away or isolate and clone them? Generally, I would think that if you want to compare these cellswith what most other labs have done then isolation within the first 6 months after birth would likely give you the highest yield. However, there is the argument that the properties of the progenitor cells are associated with their "niche" so if you are interested in modeling sarcopenia, maybe a later timepoint even 2 years is better. Good luck

Daniel,

We have isolated satellite cells (progenitor cells, myogenic cells, muscle precursor cells - whatever you want to call them) consistently from 32-mo-old rat skeletal muscle (F344xBNF1 hybrid) with great success. I have also seen in the literature that other labs have isolated muscle cells from 36- and 39-mo-old rats, so I know it is possible, but your yield may decline with older muscle. The key is to make sure you start with plenty of tissue at the beginning of the isolation procedure (similar to RNA isolations - cells beget more cells, if you know what I mean). Hope this helps.

I don't have an experience with that, however the younger rat the better I believe. Maybe you would find helpful information here:

Primary rat muscle progenitor cells have decreased proliferation and myotube formation during passages. S. Machida, E. E. Spangenburg, F. W. Booth

http://www.jove.com/video/2476/purification-of-progenitors-from-skeletal-muscle

Good luck!

With kind regards

Justyna Karolczak

Ron Allen (Arizona) has done alot of satellite cell/progenitor cell isolation from rats - you may want to check his papers.

Thank you all, your answers were very helpful.