Antinociceptive effects of radon inhalation on formalin-induced inflammatory pain in mice

Keiko Yamato, Takahiro Kataoka, Yuichi Nishiyama, Takehito Taguchi, Kiyonori Yamaoka

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)


Radon therapy is clinically useful for the treatment of inflammatory diseases. The mechanisms of pain relief remain to be fully elucidated. In this study, we investigated the antinociceptive effects of radon inhalation in a mouse model of formalin-induced inflammatory pain. Immediately, after radon inhalation at a concentration of background level (ca. 19 Bq/m3), 1,000 or 2,000 Bq/m3 for 24 h, 1.35 % formalin (0.5 % formaldehyde in saline, 20 μl) was subcutaneously injected into the hind paw of mice, and we measured licking response time. Radon inhalation inhibited the second phase of response in formalin test. Formalin administration induced nociception and increased tumor necrosis factor alpha (TNF-α) and nitric oxide (NO) levels in serum and leukocyte migration in paws. Concurrently, formalin injection decreased antioxidative functions. Radon inhalation produced antinociceptive effects, i.e.; lowered serum TNF-α and NO levels, and restored antioxidative functions. The results showed that radon inhalation inhibited formalin-induced inflammatory pain.

Original languageEnglish
Pages (from-to)355-363
Number of pages9
Issue number2
Publication statusPublished - Apr 2013


  • antioxidants
  • formalin test
  • inflammatory pain
  • nociception
  • radon inhalation

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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