title: A histological atlas of the tissues and organs of neotenic and metamorphosed axolotl.
abstract: Axolotl (Ambystoma Mexicanum) has been emerging as a promising model in stem cell and regeneration researches due to its exceptional regenerative capacity. Although it represents lifelong lasting neoteny, induction to metamorphosis with thyroid hormones (THs) treatment advances the utilization of Axolotl in various studies. It has been reported that amphibians undergo anatomical and histological remodeling during metamorphosis and this transformation is crucial for adaptation to terrestrial conditions. However, there is no comprehensive histological investigation regarding the morphological alterations of Axolotl organs and tissues throughout the metamorphosis. Here, we reveal the histological differences or resemblances between the neotenic and metamorphic axolotl tissues. In order to examine structural features and cellular organization of Axolotl organs, we performed Hematoxylin & Eosin, Luxol-Fast blue, Masson's trichrome, Alcian blue, Orcein and Weigart's staining. Stained samples from brain, gallbladder, heart, intestine, liver, lung, muscle, skin, spleen, stomach, tail, tongue and vessel were analyzed under the light microscope. Our findings contribute to the validation of the link between newly acquired functions and structural changes of tissues and organs as observed in tail, skin, gallbladder and spleen. We believe that this descriptive work provides new insights for a better histological understanding of both neotenic and metamorphic Axolotl tissues.
authors.affiliation: Department of Medical Biology, International School of Medicine, İstanbul Medipol University, Istanbul, Turkey; Regenerative and Restorative Medicine Research Center, REMER, Istanbul Medipol University, Istanbul, Turkey. Electronic address: tdemircan@medipol.edu.tr.
authors.forename: Turan
authors.initials: T
authors.lastname: Demircan
authors.affiliation: Regenerative and Restorative Medicine Research Center, REMER, Istanbul Medipol University, Istanbul, Turkey.
authors.forename: Ayşe Elif
authors.initials: AE
authors.lastname: İlhan
authors.affiliation: Department of Histology and Embryology, School of Medicine, Istanbul Medipol University, Istanbul, Turkey; Regenerative and Restorative Medicine Research Center, REMER, Istanbul Medipol University, Istanbul, Turkey.
authors.forename: Nilüfer
authors.initials: N
authors.lastname: Aytürk
authors.affiliation: Regenerative and Restorative Medicine Research Center, REMER, Istanbul Medipol University, Istanbul, Turkey.
authors.forename: Berna
authors.initials: B
authors.lastname: Yıldırım
authors.affiliation: Department of Physiology, International School of Medicine, İstanbul Medipol University, Istanbul, Turkey; Regenerative and Restorative Medicine Research Center, REMER, Istanbul Medipol University, Istanbul, Turkey.
authors.forename: Gürkan
authors.initials: G
authors.lastname: Öztürk
authors.affiliation: Department of Histology and Embryology, School of Medicine, Istanbul Medipol University, Istanbul, Turkey; Regenerative and Restorative Medicine Research Center, REMER, Istanbul Medipol University, Istanbul, Turkey. Electronic address: ilknurkeskin@medipol.edu.tr.
authors.forename: İlknur
authors.initials: İ
authors.lastname: Keskin
mesh_terms: D000558:Ambystoma mexicanum / Q000033:anatomy & histology; D000663:Amphibians / Q000033:anatomy & histology; D000818:Animals; D005704:Gallbladder / Q000033:anatomy & histology*; D008099:Liver / Q000033:anatomy & histology*; D008675:Metamorphosis, Biological / Q000502:physiology*; D012867:Skin / Q000033:anatomy & histology*; D013154:Spleen / Q000033:anatomy & histology*; D013623:Tail / Q000033:anatomy & histology*; D013963:Thyroid Hormones / Q000378:metabolism; D013974:Thyroxine / Q000378:metabolism; D014284:Triiodothyronine / Q000378:metabolism
chemical_list: D013963:Thyroid Hormones; D014284:Triiodothyronine; D013974:Thyroxine
keywords: Axolotl; Histological map; Metamorphosis; Neoteny; Thyroid hormones