[The increased level of IL-17 in stomach and up-regulated splenic Th17 cell frequency and IL-17 mRNA level in rats infected with Helicobacter pylori]. 
To investigate the variation of Th17 cell frequency and IL-17 level in rats infected with Helicobacter pylori (Hp).  A total of 30 rats were used to be infected with Hp by intragastric administration of bacterial suspension.  Every 10 rats were sacrificed after 3, 6 and 9 weeks, respectively.  The gastric tissues of rats were pathologically examined by HE staining.  The level of IL-17 in the gastric tissues of rats was detected by ELISA.  The flow cytometry was performed to determine Th17 cell frequency and reverse transcription PCR was to detect the level of IL-17 mRNA in single-cell suspensions of rat spleen.  Hp infection induced the obvious pathological changes in the rat gastric mucosa.  The level of IL-17 in the gastric tissues increased with the prolonging of the Hp infection.  Both Th17 cell frequency and IL-17 mRNA level in rat spleen cells infected with Hp at 3, 6 and 9 weeks were significantly higher than those in control rats, and they were significantly different when compared among different time points.  Hp infection could induce the damage of rat gastric mucosa and increase IL-17 level in the stomach.  Furthermore, Hp infection could up-regulate the Th17 cell frequency and IL-17 mRNA level in rat spleen cells.