MRC1 and cyst: To study the correlation between CD206+ resident macrophage accumulation at early postnatal time points and the rapid cyst formation observed in juvenile-induced cystic kidney models, we utilized a conditional Pkd2 model (CAG-CreERT2 Pkd2fl/fl, referred to as Cre+ Pkd2 mice or Pkd2 mutant mice) and induced the loss of Pkd2 at two different juvenile time points: P2 and P7.