Figure 2. Administration of an inhibitor of hydrogen sulfide (H₂S) synthesis via cystathionine γ-lyase (L-propargylglycine; PAG) exacerbates esophageal injury/inflammation in hyperglycemic rats.

Administration of PAG (25 mg/kg) resulted in a significant increase in the histological score of esophageal injury (panel A). PAG administration also reduced serum IL-10 and increased serum IL-17 levels. The effects of PAG on esophageal damage and serum IL-10 were reversed by co-adminstration of L-tryptophan (L-Trp). An inhibitor of another pathway of H₂S synthesis (CHH; O-carboxymethylhydroxylamine; 20 mg/kg) had no effect on esophageal injury, but produced similar changes to serum IL-10 and IL-17 levels as were seen in PAG-treated rats. Panel C shows the irregular hyperemia, stasis (arrows) and perivascular diapedesis that was observed in rats that on the fructose-supplemented drinking water that were treated with PAG. Panel D illustrates that this treatment also resulted in localized detachments of the epithelium from the basement membrane and destructive changes to the epithelial plate (arrow). X200 (hematoxylin and eosin staining). Bars represent the mean ± SEM of at least 6 rats/group. *p<0.05 versus the vehicle-treated group; ^ψp<0.05 versus the corresponding group not treated with L-tryptophan (one-way ANOVA and Neuman-Keuls test).