The effect of DSS treatment on adherent and goblet cell mucin content and mucin gene expression.

<p>Colonic tissues sections were stained with Periodic acid Schiff reagent to visualize adherent and goblet cell mucin content. <i>A</i>: Control rat colon on day 0 showing goblet cells with high mucin content from the base to the tip of the crypts (magenta color). <i>B</i>: DSS treatment on day 2 showing mucin filled goblet cells as well as large amount of secreted adherent mucus (single head arrow) in the lumen. <i>C</i>: DSS treatment on day 5 showing disrupted elongated basal crypts with little mucin. Goblet cells at the tips of the crypts show intense mucus secretagogue activity with loose disorganized luminal mucus (double head arrow). <i>D</i>: DSS treatment on day 7 demonstrating loss of goblet cells at the site of ulcer formation (single head arrow), dense cellular infiltrate and loss of the adherent mucus barrier. <i>E</i>: DSS treated rat on day 9 showing ruptured mucosa (single head arrow) with no evident of goblet cells at the site of damage or in the adjacent areas. Scale bar represents 25 µm. <i>F</i>: The effect of DSS treatment on Muc2 and Muc3 gene expression. The relative gene expression levels were determined by real time PCR for using mRNA extracted from control and DSS treated rats during the 9 consecutive days of DSS treatment. Expression levels were normalized using GAPDH as housekeeping gene and the mRNA levels plotted as fold change over control. Data shown are the means ± SEM of 6 animals/day. *<i>P<</i>0.05 and **<i>P<</i>0.001 compared to control colon.