Viorica Braniste and colleagues studied the development of the blood-brain barrier in embryonic mice that grow in mothers with normal, healthy gut bacteria or mothers with sterile gut bacteria. The authors observed that by injecting labeled antibodies into pregnant mice to observe embryos growing in mothers with normal intestinal flora, these antibodies were too large to normally cross the blood-brain barrier and observe brain movement. However, mice will form a complete blood-brain barrier to prevent the passage of labeled antibodies.
"On the other hand, mice in a sterile environment will form a "leaky" blood-brain barrier, allowing the entry of labeled antibodies. It is not clear how gut microbes alter the development of the blood-brain barrier, but analysis of the brains of sterile mice suggests that the paracellular space between the endothelial cells that form the blood-brain barrier is closed. It may be related to protein. As we all know, human intestinal flora will change over time, so the integrity and permeability of the blood-brain barrier may change according to the composition and diversity of bacteria.
If this situation proves to be correct (although there is no evidence yet), these findings open up the possibility of developing gut microbes into target organisms, that is, penetrating the blood-brain barrier needed for drug delivery. It can enhance gender or correct the dysfunction of the blood-brain barrier, which plays a role in many degenerative diseases.