At 8 weeks of age, male Mtf1loxP/loxP mice harboring the Mx-cre transgene (Mtf1loxP/loxP Mx-cre, abbr.: Mtf1Mx-cre) and control littermates without transgene (Mtf1loxP/loxP, abbr.: Mtf1loxP) received four intraperitoneal injections each of 300 µg synthetic double-stranded RNA polyinosinic–polycytidylic acid [pI–pC; Sigma; in a volume of 60 µl phosphate-buffered saline (PBS)] at 3 day intervals.