Expression of GHRL and GHSR in embryonic development of rats with ethylene thiourea-induced anorectal malformations

Since anorectal malformations (ARM) were associated with an extensive neuromuscular maldevelopment of the lower gastrointestinal tract and anorectum, the aim of this study was to find out ghrelin (GHRL) and growth hormone secretagogue receptor (GHSR) expression patterns during anorectal development in normal and ARM embryos, in an effort to establish the possible role of GHRL and GHSR in ARM pathogenesis. ARM was induced by ethylene thiourea (ETU) on the 10th embryonic day of rats, and cesarean was performed to harvest the hindgut. The changes of mRNA and proteins of GHRL and GHSR were evaluated in normal group (n=20) and ARM group (n=20) from E15d to E21d using quantitative real-time PCR, western blot, and immunohistochemical staining, respectively. The result display, in the normal group, the protein and mRNA expressions for GHRL and GHSR showed time-dependent changes from E15d to E21d, during which time high expressions were found on E15d and E17d and it gradually decreased after E19d and E21d. While in the ARM group, low expressions were observed on the same periods which also decreased after E19d and E21d. These data implied that in ARM embryos, an imbalance in the spatiotemporal expression of GHRL and GHSR was noted during anorectal morphogenesis from E15d to E17d, which may shed light on understanding the role of GHRL and GHSR in the development of normal and ARM embryos.