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Objective To investigate the effects and mechanisms of omega-3 polyunsaturated fatty acids (ω-3 PUFA) supplementation on colonic macroscopic and histological score , inflammatory response , and endo-plasmic reticulum stress ( ERS ) response in experimental rat models of colitis .Methods Experimental rat models of colitis were induced by trinitro-benzene-sulfonic acid (TNBS).Totally 100 male SD rats were ran-domly divided into 5 groups according to the random data tables:sham operation group ( Sham group ) , inflam-matory bowel disease group (IBD group),ω-3 PUFA supplementation group (IBD+ω-3 group), 5-aminosali-cylic acid group ( IBD +5-ASA group ) , and ERS activation 2-deoxy-D-glucose group ( IBD +ω-3 +2-DG group).Colonic macroscopic and histological scores were evaluated on days 1, 3, 7 and 14 after modeling.The serum levels of tumor necrosis factor-α(TNF-α), interleukin (IL) -1, and IL-6 were measured using en-zyme-linked immunosorbent assay , whereas ERS cytokines including glucose-regulated protein 78 ( GRP78 ) , inositol-requiring enzyme 1 (IRE-1), and C/EBP homologous protein (CHOP) were tested by Western blot. Results Compared with the Sham group , colonic macroscopic and histological score , the serum levels of in-flammation relatived factors (TNF-α, IL-1, IL-6) and ERS relatived factors (GRP78、 IRE-1, CHOP) were significantly increased on the rest of the four groups ( all P<0.001 ) .Compared with the IBD group , ω-3 PUFA supplementation reduced colonic macroscopic [7 d: 3.55 ±0.29 vs.4.37 ±0.39, P=0.03, 14 d:2.46 ±0.17 vs.3.86 ±0.21, P=0.04] and histological score [7 d: (2.56 ±0.27) scores vs.(3.45 ± 0.40) scores, P=0.02, 14 d: (2.23 ±0.20) scores vs.(3.06 ±0.26) scores, P=0.04].Meanwhile,ω-3 PUFA supplementation suppressed the expressions of inflammation [TNF-α:(43.71 ±11.39) pg/ml vs. (84.97 ±13.81) pg/ml, P=0.02, IL-1:(38.51 ±10.60) pg/ml vs.(73.04 ±12.48) pg/ml, P=0.01, IL-6:(28.91 ±7.27) pg/ml vs.(53.45 ±9.40) pg/ml, P=0.02] and ERS relatived factors (GRP78:2.41 ±0.29 vs.1.47 ±0.21, P=0.01, IRE-1:2.83 ±0.31 vs.1.23 ±0.20, P<0.001, CHOP:1.89 ± 0.17 vs.1.32 ±0.11 , P=0.04 ) .However , the salutary effects of ω-3 PUFA would been reversed by ERS activation 2-deoxy-D-glucose [ TNF-α: (72.67 ±10.37 ) pg/ml vs.(43.71 ±11.39 ) pg/ml, P =0.02, IL-1:(57.66 ±13.88) pg/ml vs.(38.51 ±10.60) pg/ml, P=0.02, IL-6: (46.10 ±9.67) pg/ml vs. (28.91 ±7.27) pg/ml, P=0.01, GRP78:1.47 ±0.21 vs.1.82 ±0.24, P=0.03, IRE-1:1.23 ±0.20 vs.2.21 ±0.23, P=0.02, CHOP:1.32 ±0.11 vs.1.61 ±0.16, P=0.04].Conclusion The salutary effects of ω-3 PUFA supplementation on the colitis induced by TNBS appear to be mediated by inhibited inflam -matory responses , which may suppress the activation of ERS response .
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Purpose The aim is to study the activity and the sildenafil selective inhibition of PDE5. Methods The PDE isoenzymes were purified from bovine penis corpus cavernosum tissue by FPLC system. PDE activity was assayed by using 3 H-cGMP as substrate, the PDE isoenzymes hydrolyzed it to 3 H-GMP, and 3 H-GMP was further hydrolyzed to 3 H-guanosine by 5′-nuclease of snake venom. Add scintillation cocktail to observe the PDE isoenzymes activity. The selective inhibitor sildenafil of different concentrations were used to observe the inhibition of PDE5. Data replotted according to procedure of Dixon plots.Results Three PDE isoenzyme peaks were purificated from bovine corpus cavernosum. The PDE of the third peak had the strongest activity of cGMP hydrolyzation which could be inhibited by sildenafil apparently.Conclusion Since PDE5 was mainly found in corpus cavernosum tissue of mammalian, and sildenafil was a selective inhibitor of PDE5. It was suggested that the third peak was PDE5. The result was in agreement with the article reported.