Milk fat globule-EGF factor 8 mRNA expression in rat splanchnic tissues during postnatal development.

Milk fat globule-EGF factor (MFG-E8) is a protein that binds to alphavbeta3/5 integrin and phosphatidylserine. It plays a role in apoptotic cell removal, tissue remodeling and intestinal epithelial wound-healing process. In the present study, we examined the expression of MFG-E8 mRNA in the small intestine, liver and lungs during postnatal development. Sprague-Dawley rats were sacrificed at different ages (E20, P0, P5, P10 and P21). Total RNA was extracted from various tissues including the small intestine, liver and lungs. The MFG-E8 mRNA expression was quantified by real-time PCR. We found that the MFG-E8 mRNA was expressed at a low level on E20 in the liver. Within 24 hours after birth, its expression was markedly increased. It was then stably expressed at high level during the postnatal period. In contrast, in the small intestine, MFG-E8 mRNA significantly decreased by more than 60% (p<0.001) within 24 hours after birth compared to E20, then it gradually regained E20 values by P10. It was persistently expressed until P21. In the lungs, MFG-E8 is constitutively expressed prenatally at E20. Its expression did not change during the postnatal period. In summary, our study indicated that MFG-E8 is extensively expressed in the small intestine, liver, and lungs. As opposed to other organs, the expression of intestinal MFG-E8 is decreased during the first week of life. It is possible that this could contribute to the predisposition of the neonatal intestine to inflammation.