title: Reduction of blood nitric oxide levels is associated with clinical improvement of the chronic pelvic pain related to endometriosis.
abstract: The objective of this prospective study was to determine the plasma levels of nitric oxide (NO) in women with chronic pelvic pain secondary to endometriosis (n=24) and abdominal myofascial pain syndrome (n=16). NO levels were measured in plasma collected before and 1 month after treatment. Pretreatment NO levels (μM) were lower in healthy volunteers (47.0±12.7) than in women with myofascial pain (64.2±5.0, P=0.01) or endometriosis (99.5±12.9, P<0.0001). After treatment, plasma NO levels were reduced only in the endometriosis group (99.5±12.9 vs 61.6±5.9, P=0.002). A correlation between reduction of pain intensity and reduction of NO level was observed in the endometriosis group [correlation = 0.67 (95%CI = 0.35 to 0.85), P<0.0001]. Reduction of NO levels was associated with an increase of pain threshold in this group [correlation = -0.53 (-0.78 to -0.14), P<0.0001]. NO levels appeared elevated in women with chronic pelvic pain diagnosed as secondary to endometriosis, and were directly associated with reduction in pain intensity and increase in pain threshold after treatment. Further studies are needed to investigate the role of NO in the pathophysiology of pain in women with endometriosis and its eventual association with central sensitization.
authors.affiliation: Faculdade de Medicina, Universidade de Fortaleza, Fortaleza, CE, Brasil.
authors.forename: M G
authors.initials: MG
authors.lastname: Rocha
authors.affiliation: Hospital Universitário, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, Brasil.
authors.forename: V A
authors.initials: VA
authors.lastname: Gomes
authors.affiliation: Departamento de Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil.
authors.forename: J E
authors.initials: JE
authors.lastname: Tanus-Santos
authors.affiliation: Departamento de Ginecologia e Obstetrícia, Hospital das Clínicas, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil.
authors.forename: J C
authors.initials: JC
authors.lastname: Rosa-e-Silva
authors.affiliation: Departamento de Ginecologia e Obstetrícia, Hospital das Clínicas, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil.
authors.forename: F J
authors.initials: FJ
authors.lastname: Candido-dos-Reis
authors.affiliation: Departamento de Ginecologia e Obstetrícia, Hospital das Clínicas, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil.
authors.forename: A A
authors.initials: AA
authors.lastname: Nogueira
authors.affiliation: Departamento de Ginecologia e Obstetrícia, Hospital das Clínicas, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil.
authors.forename: O B
authors.initials: OB
authors.lastname: Poli-Neto
mesh_terms: D000328:Adult; D059350:Chronic Pain / Q000097:blood / Q000209:etiology*; D004715:Endometriosis / Q000150:complications* / Q000601:surgery; D005260:Female; D006801:Humans; D010535:Laparoscopy; D009209:Myofascial Pain Syndromes / Q000150:complications; D009569:Nitric Oxide / Q000097:blood*; D010147:Pain Measurement; D017288:Pain Threshold / Q000187:drug effects*; D017699:Pelvic Pain / Q000097:blood / Q000209:etiology*; D011446:Prospective Studies; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D009569:Nitric Oxide