Changes in substance P and neurokinin A in gingival crevicular fluid in response to periodontal treatment

Background: The study of periodontitis provides a unique model for assessin g the involvement of neuropeptides in inflammatory disease. Aim: To investigate the effects of periodontal treatment, resulting in a re turn to periodontal health, on the levels of substance P (SP) and neurokini n A (NKA) in gingival crevicular fluid (GCF). Method: We completed a cause of non-surgical treatment for 8 subjects with periodontitis (6 females 2 males, mean age 45.1, range 38-67 years) started a course of non-surgical periodontal treatment. Clinical indices were meas ured at 7 periodontitis sites at the initial visit and at 8 weeks after the completion of treatment in each subject. A 30-s sample of GCF was collecte d from each test site using perio paper strips. Each strip was placed into 500 mu l of ice cold 0.1M PBS, pH 7.4, vortex mixed for 30 s, and then stor ed at -70 degrees C until analysed by radioimmunoassay. Results: The clinical condition of all test sites improved as a result of t he periodontal treatment. The levels (pg/30 s sample) of SP fell from 56.3 (SD 66.0) at the initial visit to 4.2 (3.1) after treatment, p=0.017. The c oncentration (pg/mu l) of SP in GCF fell from 140.6 (175.6) to 24.2 (11.1), p=0.036. The levels of NKA fell from 30.5 (17.1) to 10.6 (4.9), p=0.012 wh ereas the concentration changed little from 85.4 (43.5) to 61.6 (15.1), p=0 .41. Conclusion: The reduction in inflammation resulting from effective periodon tal treatment is associated with a reduction in the levels of tachykinins i n gingival crevicular fluid.