Figure 5. Effects of ampicillin on colonic neurogenesis.

A (i-ii) are representative images of the colon wall from a Nestin-GFP reporter mouse using a 10x objective, nestin⁺ cells express GFP and the nuclei are counterstained with DAPI (blue); B (i-ii) are representative photomicrographs of Nestin-GFP mice after immunostaining with the neuronal marker HuC/D (purple). D-F are representative photomicrographs of colonic myenteric ganglion of Nestin-creER^T2:tdTomato mice 6 days after tamoxifen induction and after immunostaining with the neuronal marker HuC/D (green); (A(i)) cells expressing Nestin-GFP (green) form an extensive network that is present in full thickenss colon wall. (A(ii)) Ampicillin treatment increases the number of Nestin-GFP cells in the myenteric plexus. (B(i)) within the colonic myenteric ganglion of Nestin-GFP mice, Nestin expressing cells (green) surround the HuC/D⁺ neurons. (B(ii)) Treatment with ampicillin results in increased number of cells expressing Nestin-GFP, while reduced the number of HuC/D⁺ neurons. (C) Grouped results of number of Nestin⁺ cells under various conditions. (* p<0.05). (D(i)) Newly formed neurons (arrow) are observed in the myenteric ganglion of control mice (D(ii)) Ampicillin treatment reduced the number of newly-formed neurons in the myenteric ganglion. (E) 10 days after discontinuing ampicillin, myenteric ganglia are filled with newly formed neurons (arrows). (F) Grouped results of mean number of newly formed neurons (expressing tdTomato) per ganglion under various conditions. (* p<0.05). Scale bar is 10 μm.