Figure 2: Paneth cell function in unchallenged control and Atg7IEC-KO mice. (a) Histological analysis of Paneth cells by trichromatic staining with alcian blue, PAS, and Elastica van Gieson (top) and by electron microscopy (EM, bottom, 2156x magnification) demonstrates smaller size of granules (black arrows) in Atg7-deficient Paneth cells compared to control Paneth cells. Large autophagosomes (white arrow) were detectable in electron microscopic pictures of IECs derived from control mice but not of IECs derived from Atg7IEC-KO mice. (b) Immunofluorescent staining of distal small intestine for lysozyme (red) reveals decreased levels of lysozyme in Atg7 deficient Paneth cells. Nuclei are shown in blue. (c) Statistical analysis of the number of cells containing granules (granular+) or lysozyme (lysozyme+) at the base of crypts in the distal small intestine of unchallenged control and Atg7IEC-KO mice ( control crypts and Atg7IEC-KO crypts for analysing granular+ cells, control crypts and Atg7IEC-KO crypts for analysing lysozyme+ cells). (d) Detection of bacteria (red) in the distal small intestine of unchallenged control and Atg7IEC-KO mice by fluorescence in situ hybridization (FISH). Nuclei are shown in blue. (e) Quantitative analysis of the transcription of antimicrobial peptide genes in the distal small intestine of unchallenged control and Atg7IEC-KO mice. Data show mean values + SEM ( control mice, Atg7IEC-KO mice).