(A, B) Transfection distance and total tdTomato+; DAPI+ cells in striatal injected samples (A), and hippocampal injected samples (B). (C, D) Quantification of tdTomato+; DAPI+ cells in every 12th brain slice in striatal injected samples (C), and hippocampal injected brain samples (D). Saline (n = 3 mice), low dose of Cre mRNA (0.125 μg μL−1; Cre mRNA 1X; n = 2 mice), high dose of Cre mRNA (0.250 μg μL−1; Cre mRNA 2X; n = 2 mice), low dose of MC3 LNP Cre mRNA (0.125 μg μL−1; MC3 Cre mRNA 1X; n = 3 mice), and high dose of MC3 LNP Cre mRNA (0.250 μg μL−1; MC3 Cre mRNA 2X; n = 2 mice).