- 著者
- 圓 純一郎 石井 則久 後藤 正道
- 出版者
- 日本ハンセン病学会
- 雑誌
- 日本ハンセン病学会雑誌 (ISSN:13423681)
- 巻号頁・発行日
- vol.80, no.1, pp.5-10, 2011-02-01 (Released:2012-02-02)
- 参考文献数
- 15
- 被引用文献数
- 2 6
Buruli ulcer is a skin disease caused by Mycobacterium ulcerans (M. ulcerans). In this review, we introduce our recent studies and other important works. Lesions of Buruli ulcer are usually painless, despite the extensive tissue necrosis. We have reported that mice inoculated with M. ulcerans show nerve degeneration and absence of pain, but the mechanism evoking the nerve damage have not been clarified. In order to define whether mycolactone, a toxic lipid produced by M. ulcerans, can induce nerve damages, we have injected mycolactone A/B to BALB/c mouse footpads. Mycolactone induced footpad swelling, and sensory test showed hyperesthesia on day 7 and 14, recovery on day 21, and hypoesthesia on days 28 and 42. Histologically, nerve bundles showed hemorrhage, neutrophilic infiltration, and loss of Schwann cell nuclei on days 7 and 14. Semithin section studies revealed vacuolar change of Schwann cells started on day 14, which subsided by day 42, but myelinated fiber density remained low. This study suggests that mycolactone directly damages nerves and is responsible for the absence of pain characteristic of Buruli ulcer. In the human lesions, presence of neuritis is reported (Rondini S, 2006), and murine studies showed "autoamputation" (Addo P, 2005). In order to prevent the serious deformities evoked by Buruli ulcer, further studies are necessary.
1 0 0 0 OA ブルーリ潰瘍(M.ulcerans感染症)における末梢神経障害の解明
ブルーリ潰瘍は、抗酸菌M.ulcerans感染による痛みのない皮膚潰瘍であるが、病変に痛みがない原因は不明であった。M.ulceransが産生する毒性脂質mycolactoneをマウス足底に注射すると、局所に知覚過敏の後に知覚鈍麻がおき、末梢神経にシュワン細胞の膨化と壊死が起こった。また、培養シュワン細胞にmycolactoneを投与すると、シュワン細胞の壊死とアポトーシスが起こった。さらに、ヒトの治療前後の皮膚生検組織でも神経の変性所見を見出した。これらの研究結果から、ブルーリ潰瘍の無痛性はmycolactoneの細胞毒性に起因することが明らかになった。