Figure 3. Intragastric butyrate gavage enhances its uptake and histone acetylation in IECs.

Immunoblot of CD326⁺ IECs from syngeneic (BALB/c → BALB/c) or allogeneic (C57BL/6J → BALB/c) BMT recipients that received vehicle or butyrate (10mg/kg). (a) Acetylated histone-H4 21 days post-BMT with densitometric analysis of three experiments combined, shown below blots; representative immunoblots shown. (b) ¹³C label incorporation of butyrate in luminal contents and intestinal tissue of the large intestine in mice gavaged with ¹³C-Butyrate or non-labeled ¹²C-Butyrate, n=6 mice per group. (c) ¹³C label incorporation in tricarboxylic acid metabolite pools of the large intestine of mice fed a bolus (2 g/kg) of ¹³C-Butyrate or ¹²C-Butyrate, n=6 mice per group. ND = not detected. (d) Levels of SLC5A8 in IECs of syngeneic and allogeneic BMT recipients 21 days following transplant, from a. (e) ChIP of butyrate treated IECs (CD326⁺) and binding of acetylated histone H4 in the promoter region of Slc5a8. (f) Weight loss on day 21 with (g) GVHD clinical score, (h) survival, and (i) intestinal histopathology 21 days post-BMT of recipients treated with intragastric vehicle or butyrate; syngeneic n=6, n=12 mice per allogeneic group. (j) Transmission electron microscopy (TEM) of intestines, isolated from BMT recipients with or without intragastric gavage of butyrate for duration of experiment; all samples were isolated 7 days following BMT and stained with ruthenium red (0.1%); arrows indicate cell-cell interface. (k) Level of FITC-dextran translocation across the GI-barrier into blood serum in butyrate treated allogeneic BMT recipients, compared to vehicle control 21 days post BMT. *P < .05; **P < .01; ***P < .0001 of ANOVA a - d, i, k; students t-test e; Mantel-Cox log-rank test g, h. Bars and error bars represent the means and standard errors of the mean, respectively.