Can I ask tip for tissue measuring(especially for RNA preparation)?

Question

I extracted RNA at mouse liver and human blood, but degradation occurs. I think, at mouse liver, too hard to measuring 50mg liver(I am newbie for animal tissue preparation) so spend several minutes. liver is soft but very small, and too hard to keep the weight. (human blood spend time for defreeze, but It degraded, too.)

for example, I want to weight 20mg mouse liver, 1. cut liver by scissors about 10mg after set zero point of scales with ep-tube. 2. cut liver almost 10mg, but it's exceed weight 2~3mg, so I have to cut it 2~3mg. 3. this scale is too small... so I spend for keep the weight for 20mg, like this: 10->23->19->19.3->19.8->21->19.8->20.

I want to ask for advice about how it faster animal tissue measuring and preparation. When preparation genomic DNA, is it OK so DNA is stable than RNA. but, when extract RNA, keep the weight fast and incubate sample at ice for prevent RNA degradation.

Answer 1

I do not have specific experience with liver tissue, but here I would do a couple of things. First, to get around your issues with weighing tissue, set an acceptable range around 20 (say, plus or minus 5mg, so ranging from 15 to 25mg) and then normalize your RNA yield to that starting weight. Second, look into ways to preserve the RNA in your tissue as you're processing it. You could try RNAlater solutions or other chemical means of stopping RNA degradation, or just snap freeze your tissue in liquid nitrogen. Good luck!