title: Interleukin-13 reduces hyperalgesia and the level of interleukin-1β in BALB/c mice infected with Leishmania major with an up-regulation of interleukin-6.
abstract: The anti-inflammatory cytokines interleukin-10 (IL-10) and interleukin-13 (IL-13) were shown to reduce hyperalgesia in some models such as rats exposed to UV rays. In addition, IL-10 was also shown to reduce hyperalgesia in high dose of Leishmania major-induced inflammation in BALB/c mice accompanied by a significant decrease in the levels of interleukin-1β (IL-1β) in the paws of infected mice, while no effect on the levels of IL-6 was observed. In this study, we injected BALB/c mice with a high dose of L. major and treated them with IL-13 (15 ng/animal) for twelve days (excluding the weekends) and hyperalgesia was assessed using thermal pain tests. Furthermore, the levels of IL-1β and IL-6 were also assessed at different post-infection days. Our results show that IL-6 and more importantly IL-1β don't play a direct role in the L. major-induced hyperalgesia and that IL-13 induces this hyperalgesia through the down-regulation of IL-1β and another proinflammatory cytokine (most probably TNF-α). Furthermore, our data show that IL-13 leads to the upregulation of the level IL-6 which initially seems to have no direct role in the induced hyperalgesia. Therefore, we suggest that the L. major-induced hyperalgesia is mainly mediated by the cytokine cascade leading to the production of sympathetic amines.
authors.affiliation: Faculty of Sciences, Department of Biology, University of Balamand, Al-Kurah, Lebanon. marckaram@terra.net.lb
authors.forename: Marc C
authors.initials: MC
authors.lastname: Karam
authors.forename: Jane E
authors.initials: JE
authors.lastname: Al-Kouba
authors.forename: Samer I
authors.initials: SI
authors.lastname: Bazzi
authors.forename: Catherine B
authors.initials: CB
authors.lastname: Smith
authors.forename: Lawrence
authors.initials: L
authors.lastname: Leung
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D006930:Hyperalgesia / Q000188:drug therapy* / Q000209:etiology*; D018793:Interleukin-13 / Q000494:pharmacology / Q000627:therapeutic use*; D053583:Interleukin-1beta / Q000378:metabolism*; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism*; D007896:Leishmaniasis / Q000150:complications*; D051379:Mice; D008807:Mice, Inbred BALB C; D010147:Pain Measurement; D017288:Pain Threshold / Q000187:drug effects; D018709:Statistics, Nonparametric; D013997:Time Factors; D015854:Up-Regulation / Q000502:physiology*
chemical_list: D018793:Interleukin-13; D053583:Interleukin-1beta; D015850:Interleukin-6