I want to block miRNA in rat uterus to find its effect on embryo implanttaion. I want to know the method of injection of miRNA inhibitor and its concentration.
You should use the same method as people transfer embryos. In your case, go via vagina en route to uterine horn and use a blunt needle. Or surgically, make a small slit on dorsolateral side and locate uterine horn and inject. It should be pretty easy.