2.2. Infection Models and Infection Measurements

Models of intestinal cryptosporidiosis using intestinal epithelial cell lines were employed, as previously described [23,24]. The neonatal murine infection model of intestinal cryptosporidiosis was used for in vivo experiments [12,25]. Neonates (5 days after birth) received C. parvum oocysts by oral gavage (10⁵ oocysts per mice) to develop intestinal cryptosporidiosis. Mice received phosphate buffered saline (PBS) by oral gavage were used as control. At 24, 48, and 72 h after C. parvum oocysts or PBS administration, animals were sacrificed, and ileum intestine tissues were collected. At least five animals from each group were sacrificed and ileum epithelium tissues were obtained for biochemical analyses. Real-time PCR, immunofluorescence microscopy, and immunohistochemistry were used to assess C. parvum infection, as previously reported [24,26]. Anti-PCNA (Proliferating cell nuclear antigen, Abcam, MA, USA) was used to stain proliferating cells.