Effect of H2S on phosphorylation of retinal p38 after ischemia-reperfusion injury (IRI). Rats were treated either with inhalation of 80 ppm H2S for 60 min at various time points after IRI or with the intravenous application of GYY 4137 or the vehicle PBS (phosphate buffer saline) alone immediately following IRI. Retinal homogenates were used for Western blot analysis. (a,c) Densitometric analysis of p38 phosphorylation after inhalation of 80 ppm H2S at 0, 1.5, and 3 h after IRI (data are mean ± SD, n = 8, ** = p < 0.01, IRI vs. IRI + 80 ppm H2S at 1.5 h) and after IRI and intravenous application of GYY 4137 (data are mean ± SD, n = 6, IRI vs. IRI + GYY 4137). (b,d) Representative Western blot images illustrating the increment in p38 phosphorylation after IRI and H2S inhalation (n = 8) and after IRI and treatment with GYY 4137 (n = 6).