title: Liver X Receptor β Is Involved in Formalin-Induced Spontaneous Pain.
abstract: Increasing evidence indicates that the liver X receptor(LXR) β modulates inflammatory pain. However, the molecular mechanisms through which LXRβ modulates pain are unclear. Here, we found that LXRβ-null mice responded more strongly to acute noxious stimuli than wild-type (WT) littermates (in the hot plate and Hargreaves tests) and had augmented tonic inflammatory pain (in the formalin test). This increased reactivity to inflammatory pain was accompanied by enhanced formalin-evoked Fos and pERK staining of second-order nociceptive neurons. Immunohistochemistry showed that the expression of CGRP, SP, and IB4 was increased in the lamina I-II of the lumbar dorsal horns in formalin-injected LXRβ knockout (KO) mice compared with the WT controls. In addition, LXRβ deletion in the mice enhanced the formalin-induced inflammation with more activated microglia and astrocytes in the spinal cord. Furthermore, the levels of pro-inflammatory cytokines (IL-1β ,TNF-α) as well as NFκB in the formalin-injected paw were elevated by the loss of LXRβ. Taken together, these data indicate that LXRβ is involved in acute as well as inflammatory pain, and thus, it may be considered as a new target for the development of analgesics.
authors: Department of Anesthesiology, Xinqiao Hospital, Third Military Medical University, Chongqing, 400038, People's Republic of China.|Department of Developmental Neuropsychology, School of Psychology, Third Military Medical University, Chongqing, 400038, China.
authors: Xiaohang
authors: X
authors: Bao
authors: Department of Developmental Neuropsychology, School of Psychology, Third Military Medical University, Chongqing, 400038, China.
authors: Yulong
authors: Y
authors: Cai
authors: Department of Developmental Neuropsychology, School of Psychology, Third Military Medical University, Chongqing, 400038, China.
authors: Ying
authors: Y
authors: Wang
authors: Department of Developmental Neuropsychology, School of Psychology, Third Military Medical University, Chongqing, 400038, China.
authors: Jinghui
authors: J
authors: Zhao
authors: Department of Developmental Neuropsychology, School of Psychology, Third Military Medical University, Chongqing, 400038, China.
authors: Xie
authors: X
authors: He
authors: Department of Anesthesiology, Xinqiao Hospital, Third Military Medical University, Chongqing, 400038, People's Republic of China.
authors: Dan
authors: D
authors: Yu
authors: Department of Anesthesiology, Xinqiao Hospital, Third Military Medical University, Chongqing, 400038, People's Republic of China.
authors: Jing
authors: J
authors: Huang
authors: Department of Anesthesiology, Xinqiao Hospital, Third Military Medical University, Chongqing, 400038, People's Republic of China.
authors: Sheng
authors: S
authors: Jing
authors: Department of Anesthesiology, Xinqiao Hospital, Third Military Medical University, Chongqing, 400038, People's Republic of China.
authors: Zhiyong
authors: Z
authors: Du
authors: Department of Anesthesiology, Xinqiao Hospital, Third Military Medical University, Chongqing, 400038, People's Republic of China. 31011@sina.com.
authors: Tiande
authors: T
authors: Yang
authors: Department of Biology and Biochemistry, Center for Nuclear Receptors and Cell Signaling, University of Houston, Houston, TX, 77054, USA.
authors: Margaret
authors: M
authors: Warner
authors: Department of Biology and Biochemistry, Center for Nuclear Receptors and Cell Signaling, University of Houston, Houston, TX, 77054, USA. jgustafs@Central.UH.EDU.|Department of Biosciences and Nutrition, Karolinska Institute, Novum, Novum, 141 86, Sweden. jgustafs@Central.UH.EDU.
authors: Jan-Ake
authors: JA
authors: Gustafsson
authors: Department of Developmental Neuropsychology, School of Psychology, Third Military Medical University, Chongqing, 400038, China. fanxiaotang2005@163.com.
authors: Xiaotang
authors: X
authors: Fan
mesh_terms: D000818:Animals; D005557:Formaldehyde / Q000633:toxicity*; D000071518:Liver X Receptors / Q000172:deficiency* / Q000235:genetics; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D010146:Pain / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism*; D010147:Pain Measurement / Q000379:methods*
chemical_list: D000071518:Liver X Receptors; D005557:Formaldehyde
keywords: Fos; LXRβ; Pain; Spinal cord; pERK