Figure 3.

Sensory deprivation inhibits complete replacement of newly generated OSNs after methimazole-induced injury. A, Time course of the experimental design. Methimazole administration (intraperitoneal, i.p.) and unilateral nostril occlusion (unilateral n.o.) were performed at day 0 (d 0) and fixation (fix.) was conducted on days 3 (d3), 7 (d7), 14 (d14), and 28 (d28). (B) Photomicrographs of representative coronal sections through the nasal septum on days 3, 7, 14, and 28 after methimazole-induced injury and unilateral nostril occlusion (injury + n.o.). Top, Lower magnification images; bottom, higher magnification of the portion of the OE depicted in top photographs indicated by the square. Left side of the image corresponds to the open side and the right side to the occluded side. Scale bars, 100 μm at low magnification, 20 μm at higher magnification. C–E, Thickness of the OE (C), number of olfactory sensory neurons OSNs (D), and number of supporting cells (E) on days 3, 7, 14, and 28 after methimazole-induced injury and unilateral nostril occlusion (injury + n.o.) and on days 14 and 28 after methimazole-induced injury only (injury only). On days 14 and 28 after injury + n.o, the OE thickness and number of OSNs in the occluded side are reduced significantly compared with those in the open side (*p < 0.05; ***p < 0.001; n.s., not significant; Mann–Whitney test). On days 14 and 28 after injury + n.o, the thickness of the OE and the number of OSNs in the OE are restored to those levels on the same days after methimazole-induced injury only (n.s., not significant; Mann–Whitney test). F, Photomicrographs of representative coronal sections stained with anti-OMP antibody through the nasal septum in the open (left) and the occluded side (right) on days 3, 7, 14, and 28 after methimazole-induced injury and unilateral nostril occlusion (injury + n.o.). Scale bar, 20 μm. G, Number of OMP-positive cells on days 3, 7, 14, and 28 after methimazole-induced injury and unilateral nostril occlusion (injury + n.o.) and on days 14 and 28 after methimazole-induced injury (injury only). On days 14 and 28 after injury + n.o., the number of OMP-positive cells on the occluded side is significantly reduced compared with that on the open side (***p < 0.001; Mann–Whitney test). On days 14 and 28 after injury + n.o, the number of OMP-positive cells is restored to those levels observed after methimazole-induced injury only at the corresponding periods (n.s., not significant; Mann–Whitney test). H, Immunohistological staining of the anti-neutrophil antibody in the OE (right) and bone marrow (left) on day 28 after methimazole-induced injury and unilateral nostril occlusion for both open and occluded sides. The OE is not stained with anti-neutrophil antibody, whereas the bone marrow as a positive control tissue is stained. Scale bars, 20 μm. I, Photomicrographs of representative coronal sections of the OE on day 28 after methimazole-induced injury and unilateral nostril occlusion (injury + n.o.). Left, Lower magnification; right, higher magnification images of the areas indicated by the squares in the left image. Left and right sides of the lower magnification image correspond to the open and occluded sides, respectively. Scale bars, 200 μm at low magnification, 20 μm at higher magnification. J–L, Thickness of the OE (J), number of OSNs (K), and number of OMP-positive cells (L) obtained in each area (l1, l2, m1, and m2) on day 28 after methimazole-induced injury and unilateral nostril occlusion (injury + n.o.). The OE is thinner and the number of OSNs and OMP-positive cells are significantly fewer on the occluded side in all subareas compared with those on the open side (*p < 0.05; **p < 0.01; ***p < 0.001; Mann–Whitney test).