I have rat retinae (from a transgenic rat model) prealably fixed and included in OCT after sucrose impregnation.

I would like to genotype these samples, because we had abnormal results in our controls and suspect that our breeding was wrong, but the animals were sacrificed without keeping some tissue. I only have these OCT samples. Do you think that PFA and OCT can be a problem for extracting the DNA?

Thank you in advance for you answer.