Figure 2. Thinner cilia layer and reduced turn-over in the OE of germfree animals.

(A₁) The OE thickness was compared between conventional and germfree animals. The cilia layer thickness was evaluated based on adenylate cyclase III (ACIII) staining, whose expression is restricted to olfactory cilia. Results were expressed as mean of the OE thickness and mean of the ACIII signal area in the OE normalized to conventional animals ± SEM (n = 8). (A_2,3) Representative transmission electron images of olfactory dendritic knob (white arrow) and associated cilia layer (x2000). (A₄) Representative image of ACIII staining in the OE. (B₁) The cellular turn-over of the OE was evaluated by quantifying the areas with cleaved caspase 3 (C3C) and PCNA stainings, taken as indices of apoptosis and proliferation levels, respectively. Results were expressed as mean of the C3C and PCNA signal area in the OE normalized to conventional animals ± SEM (n = 19). Representative image of (B₂) C3C staining with OSN ongoing apoptosis and (B₃) PCNA staining mainly present in basal cells same after (B₂). (C) The level of proliferation was further evaluated by quantification of ki67 and PCNA expression on cDNAs from olfactory mucosa. Their expression levels were normalized to that of β-actin and are given as mean ± SEM (n = 7). (*) P < 0.05.