An Intravenous Injection of Reelin Rescues Endogenous Reelin Expression and Epithelial Cell Apoptosis in the Small Intestine Following Chronic Stress.

Chronic stress disrupts the integrity of the gut environment, including leaking of the intestinal epithelium. Reelin, an extracellular matrix protein, is released from cells of the lamina propria and promotes epithelial cell proliferation and migration up the crypt-villus axis to facilitate renewal of the gut lining. In the present study, we evaluated Reelin expression and apoptosis in the small intestine of Long Evan's rats treated with recombinant Reelin (3 µg) or vehicle following 3 weeks of daily corticosterone (40 mg/kg/day) or vehicle injections. We show that Reelin- and cleaved caspase-3- immunoreactive cells are diminished in the lamina propria or epithelial cells of the gut lining following chronic stress (∼ 50% and 55%, respectively), and that a single injection of 3 µg of Reelin delivered intravenously can reverse these parameters. We also found Reelin cell counts in the small intestine did not correlate to counts in the hippocampus regardless of exposure to chronic stress or Reelin treatment. Our results suggest that Reelin may serve a protective function over gut barrier integrity through the restoration of epithelial cell turnover, and that Reelin may have a role in reversing chronic stress-induced changes to the gut environment.