Altered expression of sodium pump isoforms in the inflamed intestine of Trichinella spiralis-infected rats

We used polymerase chain reaction (PCR) and Northern analysis to examine the effect of Trichinella spiralis infection on mRNA expression of sodium pump isoforms in rat intestine. 28S RNA was coamplified as an internal standard, and the abundance of the isoformic mRNA was expressed relative to 28S RNA. As assessed by PCR and Northern analysis, the alpha 1- and beta 1-subunits were expressed in the jejunum and ileum of noninfected control rats. However, in the jejunum the levels were suppressed after 24 h of infection. The suppression became maximal by day 6 and was reversed to normal by day 23 postinfection (PI). In contrast, no suppression was observed in the noninflamed ileum of infected rats. Further analysis revealed that alpha 1-mRNA was suppressed in jejunal mucosa by 89% and in longitudinal muscle-myenteric plexus by 62% but was not suppressed in circular muscle. Western blot analysis revealed a 61% decrease in the alpha 1-subunit protein in the mucosa and a 62% decrease in longitudinal muscle, whereas there was no change in the alpha 1-protein in circular muscle on day 6 PI. In contrast, marked (89%) suppression of beta 1-mRNA was observed only in the mucosa; there was no change in either circular or longitudinal muscle on day 6 PI. These results indicate that T. spiralis infection in the rat is accompanied by a significant decrease in the alpha 1-subunit of the sodium pump in longitudinal muscle. This reduction could result from altered regulation involving pretranslational changes.(ABSTRACT TRUNCATED AT 250 WORDS)