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Sonic hedgehog (SHH) is an essential morphogen for the development of neural tube, members and somites. Variations in expression can cause abnormalities in the nervous system. This will produce teratogens, such as valproic acid (VPA), which increases the reactive oxygen species and can be counteracted with the administration of vitamin E (VE). We sought to determine the expression of SHH in the neural tube and spinal cord in mice embryos and fetuses exposed to VPA, VPA + VE and VE. For the study we used 8 groups of female mice (Mus musculus). At day 8 post-coitus (p.c.) the groups were administered as follows: groups 1 and 5, 0.3ml saline; groups 2 and 6, VPA 600 mg/kg; groups 3 and 7, VPA 600 mg / kg + VE 200 IU/kg; groups 4 and 8, VE 200 IU/kg, all treatments were given orally. On the 12th day p.c., groups 1, 2, 3 and 4 were euthanized and the remaining groups at day 17. They were fixed in Bouin solution and included in paraplast; thoracic cross sections were performed, anti-SHH polyclonal antibody (Santa Cruz, H-160, rabbit) dilution 1:100 was used. We described morphology of the positively labeled samples and measured integrated optic density and percentage of immunoreactive area. SHH expression was immunopositive in notochord and floor plate of the neural tube in embryos only 12 day p.c. In the groups treated with VPA + VE and VE immunohistochemistry showed greater intensity and percentage of immunoreactive area compared to those in the group treated with VPA (p ≤ 0.0001) in the floor plate, being similar to the control group. In the notochord, immunoreaction intensity was similar to that shown in the floor plate, with significant differences (p ≤ 0.0001), but the percentage of area showed no differences. The groups at day 17 of gestation were negative for the expression of SHH. VE regulates expression of SHH in neural tube, thus attenuating the effects of VPA. [ABSTRACT FROM AUTHOR]

Valproic Acid (VPA) is the main anticonvulsant used for epilepsy throughout the gestation period. However, when used at early stages of pregnancy, it acts as a tetarogenic agent, causing congenital malformations such as cleft-lip and/or cleft palate, abnormal genital development and spina bifida, being the latter the most frequent. This is the result of the increase of reactive oxygen species, which can be countered with the supplementation of vitamin E. The aim was determine if vitamin E minimizes the damage to the neural tube and spinal cord of mice embryos and fetuses previously exposed to VPA. Eight groups of mice were constituted. Eight days post fertilization, groups 1 and 5 were administered 0,3 ml of saline solution; groups 2 and 6 600mg/Kg of VPA, groups 3 and 7 600mg/Kg of VPA and 200UI/Kg of Vitamin E; groups 4 and 8 200 UI/Kg of Vitamin E. 12 days after fertilization, groups 1, 2, 3 and 4 were euthanized, whereas in the case of the remaining groups, the same process was performed 17 days after fertilization. The embryos were stained with cresyl violet, thus enabling the observation of histological sections at cervical, thoracic and lumbar levels. Groups supplied with vitamin E presented a lower amount of neuroblasts and motoneurons. However, these elements were bigger in size compared to the group treated with VPA (p<0,05), being these results similar to those obtained with the control groups. When comparing the neural tube and spinal cord at different levels (cervical, thoracic and lumbar), no statistically significant differences were found. It was determined that prenatal administration of vitamin E lessens the damage to the neural tube and spinal cord of mice embryos of 12 and 17 days of gestation previously exposed to VPA. [ABSTRACT FROM AUTHOR]

During embryonic development, cells in many tissues differ according to the positional information that is set by the concentration of morphogen gradients. These are signaling molecules that are secreted in a restricted region of a tissue and diffuse away from their source forming a concentration gradient. Morphogens generally act at different development stages in an organism and cause different reactions in cells depending on their history of differentiation. The best known example of morphogens are members of growth factor beta (TGF-beta), Hedgehog(Hh), and Wnt families or microRNAs. [ABSTRACT FROM AUTHOR]

The role of bone morphogenetic proteins (BMP-s) in the development of the nervous system has been widely studied on avian and rodent embryos. Human embryos have rarely been available for detection of BMP expression. In this study 39 human embryos of Carnegie stages (CS) 10-20 were investigated. The embryos were fixed in paraformaldehyde, embedded in paraffin and sectioned serially in transverse direction. BMP-2 and BMP-4 protein expression in the developing neural tube and the caudal spinal cord was determined by immunohistochemistry. Our data show that BMP-s tend to be more expressed in the neural tube in earlier stages; in particular, BMP-4 staining was found to be higher at CS10 compared to CS20. More detailed analysis was performed on embryos of CS14-18. Stronger BMP-2 and BMP-4 expression was found in the dorsal part than in the ventral part of the spinal cord. No differences were seen in the staining intensity of BMP-s in the spinal ganglia. Interestingly, in neural crest cells BMP-2 staining was stronger at CS16 and CS18 as compared to CS14, while no differences were found in BMP-4 staining. On the other hand, in the non-neural ectoderm BMP-4 staining was found to be stronger at CS16 than at CS14, while no differences were seen for BMP-2. In conclusion, expression of BMP-s in the developing neural tube and spinal cord of human embryos is generally in accordance with the findings made in rodents and birds. [ABSTRACT FROM AUTHOR]