Retinoic Acid Induces Abnormal Palate During Embryogenesis in Rat

  • Shin, Jeong-Oh (Department of Anatomy, Embryology Lab., Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine) ;
  • Park, Hyoung-Woo (Department of Anatomy, Embryology Lab., Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine) ;
  • Bok, Jin-Woong (Department of Anatomy, Embryology Lab., Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine) ;
  • Kim, Myoung-Hee (Department of Anatomy, Embryology Lab., Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine)
  • Received : 2009.12.02
  • Accepted : 2010.03.12
  • Published : 2010.03.31


In order to understand the effects of all-trans-RA on palate development, RA was injected into the abdominal cavity of pregnant mice and then the embryos were taken in the following days and analyzed morphologically as well as molecular biologically. When RA was administered at the stage of E11 or E15, the overall craniofacial development was retarded. The length from jaw to eye was shortened, compared to that of normal group. When the E11 embryos were exposed to RA, cleft lip was also found along with the cleft palate. In vitro palate culture experiment also revealed that RA caused cleft palate. When RT-PCR was performed, early stage administration of RA at E11 inhibited the upregulation of Hoxa7 expression at E15 through E17. Whereas in control group, high level of Hoxa7 expression was detected in the palate of E15 to E17. In the case of Bax, the expression was decreased from E16, while remaining constant in control group. When TUNEL analysis was performed following the RA treatment at E15, TUNEL positive cells were detected in the mesenchymal cells as well as epithelial cells of palatal shelves of E16 and in E17 embryos. Whereas in normal control, TUNEL positive cells were observed mostly at the epithelium around the nasal cavity and oral cavity where rugae is made. These results altogether indicate that exposure to RA during palate development causes facial deformity including cleft palate and cleft lip by modulating the expression of homeotic genes such as Hoxa7 as well as an apoptosis-related gene, Bax, and thus malregulating the apoptosis.


Supported by : NRF, RDA


  1. Abbott BD, Harris MW, Birnbaum LS. Etiology of retinoic acid-induced cleft palate varies with the embryonic stage. Teratology. 1989. 40: 533-553.
  2. Balling R, Mutter G, Gruss P, Kessel M. Craniofacial abnonnalities induced by ectopic expression of the homeobox gene Hoxa1.1 in transgenic mice. Cell 1989. 58: 337-347.
  3. Brickell P, Thorogood P. Retinoic acid and retinoic acid receptors in craniofacial development. Semin Cell Dev BioI. 1997. 8: 437-443.
  4. Cheng MS, Yoo BK, Park HW, Kim MH. Effect of retinoic acid on palate formation during rat embryogenesis. Korean J Anat. 2006.39: 331-341.
  5. Cuervo R, Valencia C, Chandraratna RA, Covarrubias L. Programmed cell death is required for palate shelf fusion and is regulated by retinoic acid. Dev BioI. 2002. 245: 145-156.
  6. Ferguson MWJ. Palate development: mechanisms and malformations. Irish J Med Sci. 1987. 156: 309-315.
  7. Gurley JM, Wamsley MS, Sandell LJ. Alterations in apoptosis and epithelial-mesenchymal transformation in an in vitro cleft palate model, Plast Reconstr Surg 2004. 113: 907-914.
  8. Kaiser ME, Merrill RA, Stein AC, Breburda E, Clagett-Dame M. Vitamin A deficiency in the late gastrula stage rat embryo results in a one to two vertebral anteriorization that extends throughout theaxial skeleton. Dev Biol 2003. 257: 14-29.
  9. Keith L. Moore, T.Y.N Persaud. The developing human: clinically oriented embryology. 8th edition; Philadelphia; 2008.
  10. Kessel M, Gruss P. Homeotic transformations of murine vertebrae and concomitant alteration of Hox codes induced by retinoic acid. Cell 1991. 67: 89-104.
  11. Kim S, Kim WJ, Oh C, Kim JC. Cleft lip and palate incidence among the live births in the Republic of Korea. J Korean Med Sci. 2002. 17: 49-52.
  12. Lufkin T, Mark M, Hart CP, Dolle P, LeMeur M, Chambon P. Homeotic transformation of the occipital bones of the skull by ectopic expression of a homeobox gene. Nature 1992. 359: 835-841.
  13. Marazita ML, Field LL, Cooper ME, Tobias R, Maher BS, Peanchitlertkajom S, Liu YE. Nonsyndromic cleft lip with or without cleft palate in China: assessment of candidate regions. Cleft Palate Craniofac J. 2002. 39: 149-156.<0149:NCLWOW>2.0.CO;2
  14. Marshall H, Morrison A, Studer M, Popperl H, Krumlauf R. Retinoids and Hox genes. FASEB J 1996. 10: 969-978.
  15. Martinez-Alvarez C, Tudela C, Perez-Miguelsanz J, O'Kane S, Puerta J, Ferguson MW. Medial edge epithelial cell fate during palatal fusion. Dev Biol 2000. 220: 343-357.
  16. Mclain K, Schreiner C, Yager KL, Stock JL, Potter SS. Ectopic expression of Hox-2.3 induces craniofacial and skeletal malformations in transgenic mice. Mech Dev 1992. 39: 3-16.
  17. Morriss-Kay G. Retinoic acid and development. Pathobiology 1992. 60: 264-270.
  18. Nazarali A, Puthucode R, Leung V, Wolf L, Hao Z, Yeung J. Temporal and spatial expression of Hoxa-2 during murine palatogenesis. Cell Mol Neurobiol 2000. 20: 269-290.
  19. Newall DR, Edwards JR. The effect of vitamin A on fusion of mouse palates. I. Retinyl palmitate and retinoic acid in vivo. Teratology. 1981a. 23: 115-124.
  20. Newall DR, Edwards JR. The effect of vitamin A on fusion of mouse palates. II. Retinyl palmitate, retinol, and retinoic acid in vitro. Teratology. 1981b. 23: 125-130.
  21. Srivastava HC, Rao PP. Movement of palatal shelves during secondary palate closure in rat. Teratology 1979.19: 87-103.
  22. Sulik KK, Cook CS, Webster WS. Teratogens and craniofacial malformations: relationships to cell death. Development. 1988.103 Suppl: 213-231.
  23. Whiting J. Craniofacial abnormalities induced by the ectopic expression of homeobox genes. Mutat Res 1997. 396: 97- 112.
  24. Yu J, Gonzalez S, Martinez L, Diez-Pardo JA, Tovar JA. Effects of retinoic acid onr The neural crest-controlled organs of fetal rats. Pediatr Surg Int 2003. 19: 355-358.