Figure 1
From: TGFβ2-induced senescence during early inner ear development
Senescence in the developing chicken inner ear. SAβG staining in the otic epithelium of chicken embryos at HH17 (A) and at HH20 (B) stages showing intense staining in the otic pore and in the developing endolymphatic duct (arrows). (C) Representative microphotograph of an otic vesicle cryosection SAβG stained. (D–E) SAβG staining in isolated otic vesicles from E10 mouse (D) and HH18 chicken (E) embryos showing specific labelling at the endolymphatic duct. (F) p21, Btg1 and Btg2 mRNA expression levels were measured by RT-qPCR in HH18 (white bars) and HH19 (black bars) otic vesicle explants. Gene expression was calculated as 2−ΔΔCt and normalized to the levels at HH18. The results are expressed as the means ± SEM from three independent experiments performed in triplicate. Statistical significance was determined with the Student’s t-test: **P < 0.01, ***P < 0.005, versus HH18. (G–I) SAβG staining associated to the endolymphatic duct throughout early morphological changes in an otocyst ex vivo culture. Otic vesicles were isolated from HH18 chicken embryos and cultured for 24, 48 and 72 h in free-serum medium (0S). (J) Proliferation was evaluated by EdU incorporation (red) at HH18 otic vesicles cultured ex vivo for 20 h. (K) TUNEL labelling (green) in embryo sections showed the presence of apoptotic cells in the developing endolymphatic duct. (L) Drawing summarizing the localization of senescent, apoptotic and proliferative cells in the otic vesicle. Abbreviations: Ed, endolymphatic duct; OC, otic cup; OP, otic pore; OV, otic vesicle. Orientation: A, anterior; D, dorsal. Scale bar: 80 μm. Representative microphotographs are shown from at least n = 5 otic vesicles per condition.
