RNA Degradation or DNA Contamination

[burns_newsome]

Hi all,

I have been attempting to extract RNA (RNeasy Micro Kit) from mouse retinal cells collected using laser capture microscopy, but our bioanalyzer results have been quite strange recently. The first time I ran LCM-collected samples through the bioanalyzer I got decent results, collecting somewhere between 200-500 pg/ul RNA (what I would expect given the number of cells I collect) with relatively little degradation. More recently, however, I've been picking up around 2500 pg/ul (way too high - doesn't make sense) and getting very odd bioanalyzer results.

See recent electropherograms here

For the life of me, I can't figure out what's going on. Some have told me that it's DNA contamination and others have said that it's RNA degradation. I've run non-LCM samples through the bioanalyzer and gotten fine results (though these samples have WAY more tissue) and I've tested other people's DNAses and gotten the same result.

Does anyone here have experience with RNA quality like this or know what is going on here?

Thanks,
Burns