Seasonal Expression of Extracellular Signal Regulated Kinases in the Colon of Wild Ground Squirrels (Spermophilus Dauricus)

Background: The aim of this study was to explore the localization and expression of extracellular signal regulated kinase/phospho-extracellular signal regulated kinases (ERK/pERK) in the colonic tissue of wild ground squirrels ( Spermophilus dauricus ) in the breeding season and the non-breeding season. Methods and Results: Hematoxylin-eosin staining, immunohistochemistry, real-time quantitative PCR and Western blot were used in this study. The histological results showed that the diameter of the colon lumen in the non-breeding season was larger than that in the breeding season, and the number of glandular cells in the non-breeding season was also more than those in the breeding season. The immunochemical results showed that ERK1/2 was expressed in the cytoplasm of goblet cells and intestinal epithelial cells, while pERK1/2 was expressed in the cytoplasm and nucleus of goblet cells and intestinal epithelial cells. The immunolocalization of ERK1/2 and pERK1/2 expression were more obvious in the non-breeding season, especially in intestinal epithelial cells. The results of real-time quantitative PCR and Western blot showed that the expression of ERK1/2 and pERK1/2 in the breeding season was significantly lower than that in the non-breeding season. Conclusions: : The expression of ERK1/2 and pERK1/2 in the colons of the wild ground squirrels had seasonal changes, which had significant increases in the non-breeding season comparing to those in the breeding season. This study revealed the potential role of ERK1/2 in colon to the adaptation of seasonal changes in wild ground squirrel.