Aminoguanidine has both an anti-inflammatory effect on experimental colitis and a proliferative effect on colonic mucosal cells

Background: The aim of this study was to assess the effect of aminoguanidine (AG) on developed colitis and cell proliferation. Methods: Colitis was induced by means of trinitrobenzene sulphonic acid (TNB) in male Wistar rats weighing about 250 g. Seven days after induction of TNB colitis the rats were divided into two groups at random, and one group was orally treated with 1.5 mu mol/kg AG each day. We assessed the effect of AG by measuring the mucosal damage, the ulcer area, myeloperoxidase (MPO) activity, inducible nitric oxide synthase (iNOs) activity, and nitrogen oxide in serum 7 days after the beginning of treatment. Results: AG significantly ameliorated the macroscopic damage score (AG versus control, 5.25 +/- 0.80 versus 7.50 +/- 0.50), the microscopic damage score (5.88 +/- 1.13 versus 9.25 +/- 0.31), ulcer area (0.57 +/- 0.14 versus 1.24 +/- 0.17 cm(2)), decreased MPO activity (51.5 +/- 9.4 versus 192.2 +/- 60 units/g tissue), and nitrogen oxide in serum (27.2 +/- 1.4 versus 32.3 +/- 1.8 mu M) but did not decrease iNOs activity (8732 +/- 435 versus 8672 +/- 357 cpm/g tissue). Moreover, AG accelerated T84 cell proliferation in a dose-dependent manner. Conclusions: These results suggest that AG ameliorates TNB colitis not only by its anti-inflammatory effect but also by accelerating the proliferation of colonic mucosal cells. AG, accordingly, might well be a useful new medicine to ameliorate inflammatory bowel disease.