Melanin-concentrating hormone expression in the rat hypothalamus is not affected in an experiment of prenatal alcohol exposure

Chometton S1, Franchi-Bernard G1, Houdayer C1, Mariot A1, Poncet F1, Fellmann D1, Risold PY2
1EA3922, SFR-FED 4234, UFR Sciences Médicales et Pharmaceutiques, Université de Franche-Comté, Besançon, France.
2EA3922, SFR-FED 4234, UFR Sciences Médicales et Pharmaceutiques, Université de Franche-Comté, Besançon, France. Electronic address : pierre-yves.risold@univ-fcomte.fr

Alcohol consumption during pregnancy can cause a « fetal alcoholic syndrome » (FAS) in the progeny. This syndrome is characterized by important brain defects often associated to a decreased expression of the morphogenic protein sonic hedgehog (Shh).

The goal of this study was to verify if a FAS could modify the differentiation of hypothalamic neurons producing MCH. Indeed, the expression of this peptide and neurons producing it are dependent of a Shh controlled genetic cascade in the embryo. To address this question, female rats received a 15% ethanol solution to drink during pregnancy and lactation. Higher abortion rate and smaller pups at birth confirmed that descendants were affected by this experimental condition. MCH expression was analyzed by RT-qPCR and immunohistochemistry in embryos taken at E11 and E13, or in pups and young adults born from control and alcoholic mothers. MCH expression level, number of MCH neurons or ratio of MCH sub-populations were not modified by our experimental conditions. However, Shh expression was significantly lover at E11 and we also observed that hindbrain serotonergic neurons were affected as reported in the literature.

These findings as well as other data from the literature suggest that protective mechanisms are involved to maintain peptide expressions and differentiation of some specific neuron populations in the ventral diencephalon in surviving embryos exposed to ethanol during pregnancy.

http://www.ncbi.nlm.nih.gov/pubmed/25093909
PubMed, Brain Res Bull. 2014 Aug;107:102-9. doi: 10.1016/j.brainresbull.2014.07.006. Epub 2014 Aug 2.