Would very much agree with Tiago Oliveira above. I was facing some problems with RNA isolation and would like to add that you examine the curves from the nanodrop before you run it on the gel. Good curves on nanodrop should look good on denaturing gel. All the best!
Did you try DNAse treatment after isolation?. Just to be sure there are no DNA traces in your samples. Also as Tiago already sugested denaturing electroporesis or maybe increasing the concentration of your AGE may improve resolution of your bands.
Load about 500ng of denatured (in RNA loading buffer containing formamide) on 1% agarose gels prepared in MOPS buffer. On the other hand try to interpret the nanodrop readings and curves according to the the following article
run a Formaldehyde agarose RNA gel, TRizol should give u a good RNA.. if still the problem persists maybe there could be DNA contamination.. did you do DNAse treatment