The Effects Of The Receptors Of WGA,RCA-â…  And ECL On The Development Of Normal Nerve Tube And Nerve Tube Defects Induced By Excess Retionoid Acid In Mouse

Objective:Morphogenesis of tissues and organs is a complicated process, involving morphologic change of the cells, cell movement, the recognition and adhesion among cells, cell proliferation and apoptosis. The formation and development of the neural tube is also a complicated biological process, including cell proliferation, apoptosis, differentiation, recognition, migration, function expression, and so on. The studies of recent years have proved that the development of the neural tube had not only been controlled by genes, but also involved in many regulatory factors secreted by the embryo and neural epithelium. Lectin receptors are one of the regulatory factors among them.Lectin receptors, which can combine with the specific lectins, are glycoproteins, glycolipids or glycoconjugates located on the cells.They take important roles in cell growth, differentiation, recognition and adhesion among cells. To explore the effects of the receptors of WGA,RCA-I and ECL on the development of normal nerve tube and nerve tube defects,we used Kunming mice as model systems to examine the distribution and changes of the receptors mentioned above in normal nerve tube and abnormal nerve tube induced by excess retinoid acid (RA) in mice with affinity cytochemistry. Methods:The mature female mice were mated with mature male mice. Females were checked daily for vaginal plugs (midday of plug as E0.5d). The pregnant mice were drenched vitamin A acid (30mg/kg) diluted with peanut oil in the seventh day at 18:30 after fertilization. The pregnant mice in the normal development and the pregnant mice drenched vitamin A acid were killed on day 7.5, 8.5, 9.0,9.5,10.5,11.5,12.5 of pregnancy by neck dislocation. The uteri were excised. The oncoides parts of uteri were obtained. A part of the mice embryos of pregnancy 11.5 and 12.5 day were obtained. The uteri and mice embryos were fixed with Bouin fixatire, embedded in wax, finally the specimens were sliced into section of 5μm in thickness. The distribution of WGA, RCA-I, ECL receptors on neural tube were examined with affinity cytochemistry. Results:1 The results of WGA staining: The recopors of WGA is expressed in the luminal surface and basal surface of the neural tube, and plasmalemma and cytoplasm of neurepithelium cells from day 7.5 to day 12.5. The general tendency of the exprsssin of WGA is decreaseing first, then rising, and the lowest point appears on day 9.0. The level of the expression of WGA receptor, in the cranial and caudal parts of the murine neural tube is always higher than that in the trunk of the neural tube from day 9.5 to day 12.5. In RA treated groups, the recepors of WGA is mainly expressed in the luminal surface of the neural tube, and the level of the expression of the receptors of WGA is decreasing in other parts of the neural tube. The level of the expression of the receptors of WGA in the RA treated groups is lower than that in the normal control groups.2 The results of RCA-I staining: The recopors of RCA-I is expressed in the luminal surface and basal surface of the neural tube, and plasmalemma and endochylema of neurepithelium cells from day 7.5 to day 12.5. The general tendency of the exprsssin of RCA is rising from day 7.5 to day 9.0. The general tendency of the exprsssin of RCA-I in the cranial and caudal parts of the murine neural tube is rising, but in the trunk of the neural tube is decreasing from day 9.5 to day 12.5. Thereby, the level of the expression of RCA-I receptor, in the cranial and caudal parts of the murine neural tube is always higher than that in the trunk of the neural tube from day 9.5 to day 12.5. In RA treated groups, the recepors of RCA is mainly expressed in the luminal surface of the neural tube, and the level of the expression of the receptors of RCA is decreasing in other parts of the neural tube. Moreover, the level of the expression of the receptors of RCA in the dorsum of the malformed neural tube is also very high.The level of the expression of the receptors of RCA-I in RA treated groups, is higher than that in the normal control groups.3 The results of ECL staining: The recopors of ECL is mainly expressed in the luminal surface and basal surface of the neural tube from day 7.5 to day 12.5, but the coloration of ECL in plasmalemma and cytoplasm of neurepithelium is faint or negative. The general tendency of the exprsssin of ECL is decreaseing, then rising, and the lowest point appears on day 9.0. Coloration of ECL in the malformed neural tube is essentially the same as that in the normal neural tube, but the level of the expression of the receptors of ECL in the dorsum of the malformed neural tube is very high from day 11.5 to day 12.5. The level of the expression of the receptors of ECL in the specfic stage and sites of the malformed neural tube is lower than that in the normal neural tube. Conclusion:1 The distribution ang expressing intensity of the three kinds of lectin receptors are different in the normal and developmental neural tube.2 The tendency of the exprsssin of the three kinds of lectin receptors has conspicuous difference between the neural tube from day 7.5 to 9.0 and that from day 9.5 to 12.5.This may be related to the morphology events of the neural tubeclosing.3 The expression of the three kinds of lectin receptors present regular changes.Theymay regulate the development of the neural tube.4 The decrease of expression level of the three kinds of lectin receptors, especiallythat of the WGA and RCA receptors, is interrelated with the development of nerve tube defects induced by retinoid acid.