Differing effects of exogenous and endogenous hydrogen sulphide in carrageenan-induced knee joint synovitis in the rat.
OBJECTIVE
Recent findings suggest that the noxious gas H(2)S is produced endogenously, and that physiological concentrations of H(2)S are able to modulate pain and inflammation in rodents. This study was undertaken to evaluate the ability of endogenous and exogenous H(2)S to modulate carrageenan-induced synovitis in the rat knee.


METHODS
Synovitis was induced in Wistar rats by intra-articular injection of carrageenan into the knee joint. Sixty minutes prior to carrageenan injection, the rats were pretreated with indomethacin, an inhibitor of H(2)S formation (DL-propargylglycine) or an H(2)S donor [Lawesson's reagent (LR)].


RESULTS
Injection of carrageenan evoked knee inflammation, pain as characterized by impaired gait, secondary tactile allodynia of the ipsilateral hindpaw, joint swelling, histological changes, inflammatory cell infiltration, increased synovial myeloperoxidase, protein nitrotyrosine residues, inducible NOS (iNOS) activity and NO production. Pretreatment with LR or indomethacin significantly attenuated the pain responses, and all the inflammatory and biochemical changes, except for the increased iNOS activity, NO production and 3-NT. Propargylglycine pretreatment potentiated synovial iNOS activity (and NO production), and enhanced macrophage infiltration, but had no effect on other inflammatory parameters.


CONCLUSIONS
Whereas exogenous H(2)S delivered to the knee joint can produce a significant anti-inflammatory and anti-nociceptive effect, locally produced H(2)S exerts little immunomodulatory effect. These data further support the development and use of H(2)S donors as potential alternatives (or complementary therapies) to the available anti-inflammatory compounds used for treatment of joint inflammation or relief of its symptoms.
Ekundi-Valentim
E
E
Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
Santos
K T
KT
Camargo
E A
EA
Denadai-Souza
A
A
Teixeira
S A
SA
Zanoni
C I
CI
Grant
A D
AD
Wallace
Jl
J
Muscará
M N
MN
Costa
S K
SK
D000818:Animals; D002351:Carrageenan / Q000009:adverse effects*; D006862:Hydrogen Sulfide / Q000494:pharmacology*; D007719:Knee Joint / Q000201:enzymology / Q000378:metabolism / Q000473:pathology*; D008297:Male; D009569:Nitric Oxide / Q000096:biosynthesis; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D009195:Peroxidase / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013585:Synovitis / Q000139:chemically induced* / Q000201:enzymology / Q000378:metabolism; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism
D009569:Nitric Oxide; C002744:3-nitrotyrosine; D014443:Tyrosine; D002351:Carrageenan; D009195:Peroxidase; D052247:Nitric Oxide Synthase Type II; D006862:Hydrogen Sulfide