Hydrogen sulfide (H2S) has been shown to induce the activation of
neurogenic inflammation especially in normal airways and urinary bladder. However, whether endogenous H2S would regulate
sepsis-associated
lung inflammation via
substance P (SP) and its receptors remains unknown. Therefore, the aim of the study was to investigate the effect of H2S on the pulmonary level of SP in cecal
ligation and
puncture (CLP)-induced
sepsis and its relevance to
lung injury. Male Swiss mice or male
preprotachykinin-A gene knockout (PPT-A-/-) mice and their wild-type (PPT-A+/+) mice were subjected to CLP-induced
sepsis. DL-
propargylglycine (50 mg/kg i.p.), an inhibitor of H2S formation was administered either 1 h before or 1 h after the induction of
sepsis, while
NaHS, an H2S donor, was given at the same time as CLP.
L703606, an inhibitor of the
neurokinin-1 receptor was given 30 min before CLP. DL-
propargylglycine pretreatment or posttreatment significantly decreased the PPT-A gene expression and the production of SP in lung whereas administration of
NaHS resulted in a further rise in the pulmonary level of SP in
sepsis. PPT-A gene deletion and pretreatment with
L703606 prevented H2S from aggravating
lung inflammation. In addition, septic mice genetically deficient in PPT-A gene or pretreated with
L703606 did not exhibit further increase in lung permeability after injection of
NaHS. The present findings show for the first time that in
sepsis, H2S up-regulates the generation of SP, which contributes to
lung inflammation and
lung injury mainly via activation of the
neurokinin-1 receptor.