Hydrogen sulphide is a mediator of carrageenan-induced hindpaw oedema in the rat

Abstract

Hydrogen sulphide (H(2)S) is a naturally occurring gas, with potent vasodilator activity. In this report, we identify a role for H(2)S in carrageenan-induced hindpaw oedema in the rat. Intraplantar injection of carrageenan (150 microl, 2% (w v(-1))) resulted in an increase in hindpaw H(2)S synthesising enzyme activity and increased myeloperoxidase (MPO) activity. Pretreatment (i.p. 60 min before carrageenan) with DL-propargylglycine (PAG, 25-75 mg kg(-1)), an inhibitor of the H(2)S synthesising enzyme cystathionine-gamma-lyase (CSE), significantly reduced carrageenan-induced hindpaw oedema in a dose-dependent manner (e.g. increase in hindpaw weight at 3 h, saline: 0.12+/-0.017 g; carrageenan, 1.39+/-0.037 g; PAG, 50 mg kg(-1), 1.11+/-0.06 g, n=10) and MPO activity (fold increase) in the hindpaw (saline: 1.0+/-0.12; carrageenan, 2.92+/-0.45 g; PAG, 50 mg kg(-1), 1.1+/-0.22, n=10); PAG (50 mg kg(-1)) also inhibited H(2)S synthesising enzyme activity (nmol microg DNA(-1)) in the hindpaw in a dose-dependent manner (saline, 0.46+/-0.05; carrageenan, 0.71+/-0.08 g; PAG, 50 mg kg(-1), 0.17+/-0.05, n=10).

Figure 1

Effect of intraplantar carrageenan (Carr) injection on H₂S synthesising enzyme activity in the hindpaw and the effect of different doses of PAG on enzyme activity. Hindpaws were removed 3 h after carrageenan injection and assayed for enzyme activity. Results show mean±s.e.m., n=10, ^*P<0.05, c.f. control (administered intraplantar saline), ⁺P<0.05, c.f. carrageenan. Doses of PAG shown are mg kg⁻¹ (i.p.).

Figure 2

Effect of carrageenan (Carr) injection on hindpaw oedema at 3 h (panel a) and MPO activity (panel b) and the effect of different doses of PAG. Results show mean±s.e.m., n=10, ^*P<0.05, c.f. control, (administered intraplantar saline), ⁺P<0.05, c.f. carrageenan. Doses of PAG shown are mg kg⁻¹ (i.p.).