13-cis-retinoic acid alters neural crest cells expressing Krox-20 and Pax-2 in macaque embryos

Citation
N. Makori et al., 13-cis-retinoic acid alters neural crest cells expressing Krox-20 and Pax-2 in macaque embryos, ANAT REC, 255(2), 1999, pp. 142-154
Citations number
45
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Experimental Biology
Journal title
ANATOMICAL RECORD
ISSN journal
0003-276X → ACNP
Volume
255
Issue
2
Year of publication
1999
Pages
142 - 154
Database
ISI
SICI code
0003-276X(19990601)255:2<142:1AANCC>2.0.ZU;2-H
Abstract
This study investigates hindbrain and associated neural crest (NCC), otocys t, and pharyngeal arch development in monkey embryos following teratogenic exposure to 13-cis-retinoic acid (cRA), cRA was orally administered (5 mg/k g) to pregnant long-tailed macaques (Macaca fascicularis) between gestation al days (GD) 12 and 27. Embryos were surgically collected at desired stages during treatment, analyzed for external morphological changes, and process ed for immunohistochemistry. Two transiently expressed nuclear proteins, Kr ox-20 and Pax-2, were used as markers for the target cellular and anatomica l structures. Rhombomere (r) expression patterns of Pax-2 (r4/r6) and Krox- 20 (r3/r5) were maintained after cRA treatment, but r4 and r5 were substant ially reduced in size. In untreated embryos, Krox-20 immunoreactive NCC der ived from r5 migrated caudally around the developing otocyst to contribute to the third pharyngeal arch mesenchyme. In cRA-treated embryos, a subpopul ation of NCC rostral to the otocyst also showed Krox-20 immunoreactivity, b ut there was a substantial reduction in Krox-20 post-otic NCC. Pax-2 immuno reactive NCC migrating from r4 to the second pharyngeal arch were substanti ally reduced in numbers in treated embryos. Alteration in the otic anlage i ncluded delayed invagination, abnormal relationship with the adjacent hindb rain epithelium, and altered expression boundaries for Pax-2. cRA-associate d changes in the pharyngeal arch region due to cRA included truncation of t he distal portion of the first arch and reduction in the size of the second arch. These alterations in hindbrain, neural crest, otic anlage, and phary ngeal arch morphogenesis could contribute to some of the craniofacial malfo rmations in the macaque fetus associated with exposure to cRA. Anat Rec 255 :142-154, 1999. (C) 1999 Wiley-Liss, Inc.