Dear Zhigang. 

I have worked with a lot of human reproductive tissues, as well as other organ material over the years, and integrity of RNA in tissue samples is most often dependent on the initial collection process.  Tissue samples that are collected and then processed immediately after they are surgically removed (and not left to sit around for hours) are usually very reliable.  At collection they can be either immediately dissected into small pieces and placed in a stabilising solution (RNAlater), or frozen immediately on dry ice.  it sounds like you haven't had control of this collection?  Nor do you say whether the material is human or animal? 

If it is human material, and impossible to get this sort of access to the surgery, another strategy is to see if you can get formalin-fixed (paraffin embedded) material, and then use one of the several kits that are available which in our experience work well on archived materials.  Good luck. 

Simon Riley, University of Edinburgh, Manager - Edinburgh Reproductive Tissues BioBank 

Thanks, Simon. I collected animal sample and stabilized them in RNAlater (according to industry protocol). I collected ovary, testis, brain, and liver at the same time. The integrity of RNA from all others sample are good (RIN 8-10), except from ovary (RIN 4-7). I'm thinking probably it is because of the characteristic of the sample, e.g. ovary contain very high level RNase, rather than collection or isolation process, because I used the same protocol for all the samples. 

Dear Zhigang,

My laboratory routinely uses RNAlater to preserve our ovarian samples and we have been getting good results. At necropsy we collect the ovarian tissue first and process it quickly by chopping the tissue into 1 mm cubes followed by immediate storage in RNAlater (20:1 vol:tissue) at 4 C overnight. Samples are then transferred to the ultracold freezer the next morning where they are stored until analysis. I refer you to our recent publication in Furlong H.C. et al (2015) Biol Reprod. (in press). The text has been upload to Research Gate to make it easy for you to obtain.

Good luck with your samples.

 Thanks Dr. Foster. I will follow your protocol for the future sampling. 

Dear Zhigang

I agree with Warren - chopping up the ovary, which i would describe as "dense", is important to allow the RNAlater to penetrate.  I am not sure if there are any tissue penetration studies, but if RNAlater enters tissue at a similar rate to formalin fixation, it may be penetration of 1-2mm/hr?  It will certainly not be instantaneous. This may provide some insight into how to best optimise you collection and stabilisation of the tissue.  Good luck! Simon

Thanks, Dr. Riley, it is helpful. 

This is the answer to the question. 

Ribosome RNA Profiling to Quantify Ovarian Development and Identify Sex in Fish

Scientific Reports 7(1) · June 2017

DOI: 10.1038/s41598-017-04327-y 

Article Ribosome RNA Profiling to Quantify Ovarian Development and I...