Protocol for in vivo transfection of mRNA-encapsulated lipid nanoparticles in mouse testis.

Male infertility affects 10%-20% of the population in most countries, with approximately half of the cases attributed to male factors. Here, we present a protocol for in vivo transfection of mRNA-encapsulated lipid nanoparticles (mRNA-LNPs) into the mouse testis. We describe steps for mRNA-LNP preparation, rete testis delivery, and assessment of transfection and spermatogenic rescue. This protocol establishes a relatively safe and efficient testis transfection system, offering a potential therapeutic strategy for patients with spermatogenic failure.