Pain Management and Research
Role of astrocyte activation in midbrain periaqueductal gray in a rat model of neuropathic pain
Huadong Ni, Bo Lu, Ming Yao, Bing Huang, Longsheng Xu, Ying Zheng, Yong Fei, Hanqi Wang, Hongbo Li, Wenyu Chen
Published 2016-07-20
Cite as Chin J Anesthesiol, 2016, 36(7): 823-826. DOI: 10.3760/cma.j.issn.0254-1416.2016.07.013
Abstract
ObjectiveTo investigate the role of astrocyte activation in the midbrain periaqueductal gray (PAG) in a rat model of neuropathic pain.
MethodsA total of 72 male Sprague-Dawley rats, aged 9 weeks, weighing 200-250 g, were randomly divided into 5 groups using a random number table: normal control group (group C, n=8), sham operation group (group S, n=8), neuropathic pain group (group NP, n=32), normal saline control group (group NS, n=12), and fluorocitrate (an astrocyte inhibitor) group (group FC, n=12). Neuropathic pain was induced by chronic constriction injury (CCI) to the sciatic nerve in NP, NS and FC groups.In group FC, 10 pmol fluorocitrate 0.5 μl was injected into the nuclei of the ventrolateral PAG on day 14 after CCI, and the equal volume of normal saline was given instead in group NS.Eight rats in C and S groups, 8 rats before CCI, on days 3, 7, 14 and 21 after CCI in group NP, and 8 rats in NS and FC groups were selected, and the mechanical pain threshold was measured before CCI, on day 14 after CCI and at 30, 45, 60, 75, 90 and 105 min after administration.After measurement of the mechanical pain threshold, the rats were sacrificed, and the midbrain PAG was isolated for determination of the expression of astrocyte marker glial fibrillary acidic protein by immunofluorescence.
ResultsCompared with group C, the mechanical pain threshold was significantly decreased on days 3, 7, 14 and 21 after CCI, the number of activated astrocytes in the PAG was significantly increased on days 7, 14 and 21 after CCI in group NP (P<0.01), and no significant change was found in the parameters mentioned above in group S (P>0.05). Compared with group NS, the mechanical pain threshold at each time point after adiministration was significantly increased, and the number of activated astrocytes in the PAG was significantly decreased in group FC (P<0.01).
ConclusionAstrocyte activation in the midbrain PAG is involved in the maintenance of neuropathic pain in rats.
Key words:
Astrocytes; Cerebral aqueduct; Periaqueductal gray; Neuralgia
Contributor Information
Huadong Ni
Department of Anesthesia and Pain Research Center, First Affiliated Hospital of Jiaxing University, Jiaxing 314000, China
Bo Lu
Department of Anesthesia, Ningbo NO.2 Hospital, Ningbo 315010, Zhejiang Province, China
Ming Yao
Department of Anesthesia and Pain Research Center, First Affiliated Hospital of Jiaxing University, Jiaxing 314000, China
Bing Huang
Department of Anesthesia and Pain Research Center, First Affiliated Hospital of Jiaxing University, Jiaxing 314000, China
Longsheng Xu
Department of Anesthesia and Pain Research Center, First Affiliated Hospital of Jiaxing University, Jiaxing 314000, China
Ying Zheng
Department of Anesthesia and Pain Research Center, First Affiliated Hospital of Jiaxing University, Jiaxing 314000, China
Yong Fei
Department of Anesthesia and Pain Research Center, First Affiliated Hospital of Jiaxing University, Jiaxing 314000, China
Hanqi Wang
Department of Anesthesia and Pain Research Center, First Affiliated Hospital of Jiaxing University, Jiaxing 314000, China
Hongbo Li
Department of Anesthesia, Second Affiliated Hospital &
Yuying Children′s Hospital of Wenzhou Medical University, Wenzhou 325000, China
Wenyu Chen
Department of Pneumology, First Affiliated Hospital of Jiaxing University, Jiaxing 314000, China
