1) Go to the website “Science in the Classroom” and pull up the article “You are what you eat…at least, your brain is”: (opens in new window). For this assignment, you will focus only on the results and conclusion (these can be found in the “report” section).
2) In your own words, summarize the conclusion. Be sure to address if the scientist answered their original question.
• Your summary should be at least 100 words.
3) RESULTS
4) The maternal gut microbiota can influence prenatal development of the BBB
5) First, we characterized BBB permeability of mouse embryos with pathogen-free mothers by administering infrared-labeled immunoglobulin G2b (IgG2b) antibody to dams during timed pregnancies to see whether the antibody was excluded by the BBB or was able to cross the BBB into the brain parenchyma. The qualitative analysis of mouse embryos with pathogen-free mothers showed a shift from a diffuse infrared-labeled antibody signal present within the embryonic brain at E13.5 and E14.5 to a signal confined to the developing vasculature starting at E15.5 to E17.5 (Fig. 1A). This signal was most pronounced in adult offspring of pathogen-free dams (Fig. 1A). The quantitative analysis of the penetration into the fetal brain of infrared-labeled IgG2b antibody injected intravenously into pathogen-free dams supported the qualitative data, showing a decrease at E15.5 to E17.5 (Fig. 1B). In contrast, the analysis of E16.5 brains from fetal mice of germ-free dams showed a diffuse signal from the infrared-labeled IgG2b antibody (Fig. 1C) present in the brain parenchyma (Fig. 1, D and E). Higher-magnification images of the brain showed that the IgG2b antibody was limited only to the vessels in E16.5 fetal mice of pathogen-free dams in contrast to age-matched fetal mice of germ-free dams (Fig. 1, D and E). Because BBB integrity is controlled in part by sealing of the endothelial cells via tight junctions, we determined expression of the main tight junction proteins in brain lysates from E18.5 fetal mice of pathogen-free versus germ-free dams. Expression of the brain endothelial tight junction proteins claudin-5 and ZO-1 was similar between the two groups, whereas the expression of occludin was significantly lower in the brain lysates from E18.5 fetal mice of germ-free dams compared to that in age-matched fetal mice of pathogen-free dams
Scientist main question:
Is the BBB more permeable (leaky) during the embryonic development of germ-free mice, compared with pathogen-free mice?