Here is the protocol that I used to extract bacterial RNA from tissue culture

http://emerald.tufts.edu/~mcourt01/Documents/Trizol_protocol.pdf

Good luck

Triturate the tissue and try the Tri-reagent method (Trizol)

you can follow these references 

1. Chomczynski, P., and Sacchi, N. (1987) Anal. Biochem. 162, 156.

2. Chomczynski, P. (1993) Biotechniques 15, 532.

3. Ausubel, F.M., et.al, eds. (1990) Current Protocols in Molecular Biology, Vol.2, Greene

Publishing Assoc. and Wiley-Interscience, New York, p.A.1.5.

4. Simms, D., Cizdziel, P.E., Chomczynski, P. (1993) FOCUS® 15, 99.

5. Bracete, A.M., Fox, D.K., and Simms, D. (1998) FOCUS 20, 82).