Borghi Sergio M, Fattori Victor, Ruiz-Miyazawa Kenji W, Miranda-Sapla Milena M, Casagrande Rúbia, Pinge-Filho Phileno, Pavanelli Wander R, Verri Waldiceu A
Departamento de Ciências Patológicas, Centro de Ciências Biológicas, Universidade Estadual de Londrina, Rod. Celso Garcia Cid PR445 KM380, 86057-970 Londrina, Paraná, Brazil.
Departamento de Ciências Farmacêuticas, Centro de Ciências da Saúde, Hospital Universitário, Universidade Estadual de Londrina, Av. Robert Koch, 60, 86038-350 Londrina, Paraná, Brazil.
Chem Biol Interact. 2017 Apr 25;268:1-12. doi: 10.1016/j.cbi.2017.02.009. Epub 2017 Feb 17.
Cutaneous leishmaniasis (CL) is the most common form of the leishmaniasis in humans. Ulcerative painless skin lesions are predominant clinical features of CL. Wider data indicate pain accompanies human leishmaniasis, out with areas of painless ulcerative lesions per se. In rodents, Leishmania (L.) major infection induces nociceptive behaviors that correlate with peripheral cytokine levels. However, the role of the spinal cord in pain processing after Leishmania infection has not been investigated. Balb/c mice received intraplantar (i.pl.) injection of Leishmania (L). amazonensis and hyperalgesia, edema, parasitism, and spinal cord TNFα, TNFR1 and TNFR2 mRNA expression, and NFκB activation were evaluated. The effects of intrathecal (i.t.) injection of morphine, TNFα, TNFα inhibitors (etanercept and adalimumab) and NFκB inhibitor (PDTC) were investigated. The present study demonstrates that Leishmania (L.) amazonensis infection in balb/c mice induces chronic mechanical and thermal hyperalgesia in an opioid-sensitive manner. Spinal cord TNFα mRNA expression increased in a time-dependent manner, peaking between 30 and 40 days after infection. At the peak of TNFα mRNA expression (day 30), there was a concomitant increase in TNFR1 and TNFR2 mRNA expression. TNFα i.t. injection enhanced L. (L.) amazonensis-induced hyperalgesia. Corroborating a role for TNFα in L. (L.) amazonensis-induced hyperalgesia, i.t. treatment with the TNFα inhibitors, etanercept and adalimumab inhibited the hyperalgesia. L. (L.) amazonensis also induced spinal cord activation of NFκB, and PDTC (given i.t.), also inhibited L. (L.) amazonensis-induced hyperalgesia, and spinal cord TNFα, TNFR1 and TNFR2 mRNA expression. Moreover, L. (L.) amazonensis-induced spinal cord activation of NFκB was also inhibited by etanercept and adalimumab as well as PDTC i.t.
These results demonstrate that endogenous spinal cord TNFα and NFκB activation contribute to L. (L.) amazonensis-induced hyperalgesia in mice. Thus, spinal cord TNFα and NFκB are potential therapeutic targets for Leishmania infection-induced pain.
皮肤利什曼病（CL）是人类利什曼病最常见的形式。溃疡性无痛皮肤病变是CL的主要临床特征。更广泛的数据表明，疼痛伴随人类利什曼病出现，不仅限于无痛溃疡性病变本身的区域。在啮齿动物中，亚马逊利什曼原虫（L.）主要感染会诱发与外周细胞因子水平相关的伤害感受行为。然而，脊髓在利什曼原虫感染后疼痛处理中的作用尚未得到研究。对Balb/c小鼠进行足底内（i.pl.）注射亚马逊利什曼原虫（L.），并评估痛觉过敏、水肿、寄生虫感染情况以及脊髓肿瘤坏死因子α（TNFα）、肿瘤坏死因子受体1（TNFR1）和肿瘤坏死因子受体2（TNFR2）的信使核糖核酸（mRNA）表达，以及核因子κB（NFκB）的激活情况。研究了鞘内（i.t.）注射吗啡、TNFα、TNFα抑制剂（依那西普和阿达木单抗）和NFκB抑制剂（吡咯烷二硫代氨基甲酸盐，PDTC）的效果。本研究表明，Balb/c小鼠感染亚马逊利什曼原虫（L.）会以阿片类药物敏感的方式诱发慢性机械性和热性痛觉过敏。脊髓TNFα mRNA表达呈时间依赖性增加，在感染后30至40天达到峰值。在TNFα mRNA表达峰值（第30天）时，TNFR1和TNFR2 mRNA表达同时增加。鞘内注射TNFα增强了亚马逊利什曼原虫（L.）诱导的痛觉过敏。鞘内注射TNFα抑制剂依那西普和阿达木单抗可抑制痛觉过敏，这证实了TNFα在亚马逊利什曼原虫（L.）诱导的痛觉过敏中的作用。亚马逊利什曼原虫（L.）还诱导脊髓NFκB激活，鞘内注射PDTC也可抑制亚马逊利什曼原虫（L.）诱导的痛觉过敏以及脊髓TNFα、TNFR1和TNFR2 mRNA表达。此外，依那西普、阿达木单抗以及鞘内注射PDTC也抑制了亚马逊利什曼原虫（L.）诱导的脊髓NFκB激活。
这些结果表明，内源性脊髓TNFα和NFκB激活促成了亚马逊利什曼原虫（L.）诱导的小鼠痛觉过敏。因此，脊髓TNFα和NFκB是利什曼原虫感染诱导疼痛的潜在治疗靶点。
