Role of p38MAPK signal transduction pathway in cerebral fractalkine-induced hyperalgesia in mice / 中华麻醉学杂志

ABSTRACT

Objective To determine whether p38 mitogen-activated protein kinase (p38MAPK) signaling pathway is involved in cerebral fractalkine-induced hyperalgesia in mice.Methods Two hundred and twenty-five male Kunming mice weighing 30-40 g were randomly divided into 4 groupsgroup control ( group C,n =55 ) ;group fractalkine (group F,n =60); group anti-CX3CR1 + fractalkine (group CF,n =55) and group SB203580 (p38MAPK inhibitor) + fractalkine (group SF,n =55).Fractalkine 100 ng was injected into cerebral lateral ventricle (i.c.v.) in groups F,CF and SF.Anti-CX3CR1 1 μg and SB203580 1 μg were injected i.c.v.at 1 h before fractalkine injection in groups CF and SF respectively.Paw withdrawal latency to a thermal nociceptive stimulus (PWL) was measured at 30 min before the drugs were injected into cerebral lateral ventricle and 30,60,120 and 240 min after fractalkine injection.Five animals were sacrificed after PWL measurement at each time point and their brains were removed for determination of phosphorylated p38MAPK protein expression (by Western blot analysis).Five animals were sacrificed at 30 min before the drugs were injected into cerebral lateral ventricle and 6,12 and 24 h after fractalkine injection for determination of IL-1β and TNF-α contents in the brain (by ELISA) in all the 4 groups.In group F 5 animals were sacrificed at 4 h after fractalkine injection for determination of action of fractalkine on microglia or astrocyte (by immunofluorescence).Results Fractalkine i.c.v.injection significantly reduced PWL and increased phosphorylated 38MAPK,IL-1β and TNF-α levels in group F as compared with group C.Pretreatment with anti-CX3CR1 or SB203580 significantly decreased fractalkine-induced hyperalgesia and phosphorylated-p38MAPK,IL-1β and TNF-α levels in groups CF and SF as compared with group F.Fractalkine was localized at microglia.Conclusion p38MAPK signal transduction pathway is involved in cerebral fractalkine-induced hyperalgesia in mice.