Effect and mechanism of bromodomain-containing protein 4 inhibitor JQl on formaldehyde solution induced inflammatory pain in mice / 解剖学报

Objective To explore the expression and role of bromodomain-containing protein 4(BRD4) in spinal cord of mice which suffered inflammatory pain induced by formaldelryde solution. Methods Thirty-two ICR mice were randomly divided into normal saline group and formaldehyde injection 5 minutes, 30 minutes and 60 minutes groups, with 8 mice in each group. The expression of BRD4 protein and mRNA in spinal cord of mice in each group were detected by Western blotting (n = 4/group) and Real-time PCR (n = 4/group); 66 mice were randomly divided into formaldelryde injection group, vehicle (DMSO) plus formaldelryde injection group and 6. 25, 12. 5, 25 and 50 mg/kg JQl injection plus formaldelryde solution group, with 11 mice in each group. The effect of BRD4 inhibitor JQl on spontaneous pain in each group was observed (n= 11/group); Immunohistochemistry (n= 3/group), Real-time PCR (n = 4/group) or Western blotting (n= 4/group) were used to detect the effects of 25 mg/kg JQ1 on the expression of c-fos and glutamate receptor 2 (GluR2) in the spinal cord of model mice. Results The result showed that levels of BRD4 protein (P<0. 01) and mRNA in spinal cord increased significantly 30 min and 60 min after formaldehyde solution injection (P<0. 05). The behavioral test showed that both 25 mg/kg and 50 mg/kg JQf administration could reduce the second phase spontaneous pain compared with the solvent (DMSO) group (P < 0 . 05). Furthennore, immunohistochemistry and Real-time PCR result showed that 25 mg/kg JQf injection could significantly reduce positive numbers (P<0. 01) and high mRNA expression of c-fos in mouse spinal cord induced by formaldehyde solution (P < 0 . 05), and the Western blotting result showed that 25 mg/kg JQf administration could significantly reduce the expression of glutamate receptor GluR2 (P < 0. OOf). Conclusion BRD4 may play an important role in the induction of central sensitization of inflammatory pain, and JQf may alleviate inflammatory pain behavior by inhibiting the formation of central sensitization of pain.

Effect of Huanglian Jiedutang on Learning and Memory Ability and Cholinergic System in AD Rats Induced by Aβ1-42 / 中国实验方剂学杂志

Objective:To investigate the effects of Huanglian Jiedutang on learning and memory ability and the cholinergic system in Alzheimer's disease（AD） rats induced by amyloid <italic>β</italic>-protein（A<italic>β</italic>）_1-42. Method:Sixty male SD rats were divided into normal group， model group， huperzine A group （2.1×10^-5 g·kg^-1）， high-， medium- and low dose of Huanglian Jiedutang groups （6，3，1.5 g·kg^-1）. AD rat model was replicated by hippocampal injection of A<italic>β</italic>_1-42. After 4 weeks of treatment， Morris water maze test was performed. Hematoxylineosin （HE） staining was used to observe the pathological changes of rat hippocampus. Sampling blood from abdominal aorta was taken. Acetylcholine （ACh）， acetylcholinesterase （AchE） and choline acetyltransferase （ChAT） in serum and hippocampus were detected by enzyme-linked immunosorbent assay （ELISA）. The expression of hippocampal <italic>α</italic>7 nicotinic acetylcholine receptor （<italic>α</italic>7nAChR） protein was detected by Western blot. The expression of hippocampal <italic>α</italic>7nAChR mRNA was detected by Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR）. Result:Compared with the normal group， there were obvious pathological changes in the model group，such as neuron necrosis in the cerebral cortex，pyramidal cell or granular cell necrosis in the hippocampus，disorder of arrangement and inflammatory cell infiltration，prolonged escape latency，decreased escape platform times，decreased residence time in the effective area and swimming path in the effective area （<italic>P<</italic>0.05，<italic>P<</italic>0.01）. The contents of <italic>α</italic>7nAChR mRNA，ACh，AchE，ChAT，<italic>α</italic>7nAChR in the hippocampus decreased （<italic>P<</italic>0.01）. Compared with the model group，the escape latency of the middle dose group was shorter （<italic>P<</italic>0.05）， the escape platform times，the swimming path in the effective area and the residence time in the effective area increased （<italic>P<</italic>0.05，<italic>P<</italic>0.01）， the contents of serum ACh，ChAT， hippocampal AchE，ChAT and <italic>α</italic>7nAChR increased （<italic>P<</italic>0.05，）. The expression of hippocampal <italic>α</italic>7nAChR protein significantly increased （<italic>P<</italic>0.01）， the residence time of effective area in high dose group was prolonged （<italic>P<</italic>0.01）， the times of escape platform increased，and the contents of serum ACh，ChAT and hippocampal ACh，AchE，<italic>α</italic>7nAChR protein and <italic>α</italic>7nAChR mRNA increased （<italic>P<</italic>0.05）. Conclusion:Huanglian Jiedutang can significantly improve the learning and memory ability of AD rats induced by A<italic>β</italic>_1-42，and its mechanism may be related to the improvement of cholinergic system damage and enhancement of cholinergic system function induced by A<italic>β</italic>_1-42.

Voluntary wheel running prevents the formaldehyde induced negative emotion through up-regulation of hippocampal neurogenesis in mice / 解剖学报

Objective To investigate the effect of voluntary wheel running on negative affective of mice induced by formaldehyde. Methods Thirty male Kunming mice were randomly divided into three groups, including normal saline control group (NS), formaldehyde model group (F), and voluntary wheel running with formaldehyde injection group ( R+ F). The pain model was established by right hindpaw intraplantar formalin injection, the mice of R+F group experienced voluntary wheel running for three weeks before intraplantar formaldehyde injection. The spontaneous pain behavior was determined by the cumulative time of licking paw. The anxiety-like behavior of each group was determined by open field test (OFT) and elevated plus-maze test (EPM) while the depression-like behavior of each group was determined by forced swimming test (FST). The expression of doublecortin ( DCX ) in the hippocampus was determined by immunohistochemistry. Results Compared with the NS group, the typical two-phase pain response was observed in the F group, and compared with the F group, the second phase pain duration was significantly reduced in the R+F group (P<0. 01). In the open field test, the F group showed remarkably reduced time in the inner area(P<0. 001) compared with the NS group, while the R+F group increased time in the inner area (P<0. 05) compared with the F group. In the elevated plus-maze test, the F group showed remarkably reduced time (P< 0. 001) spent in the open arm compared with the NS group, however, compared with the F group, R+F group increased time spent in the open arm (P<0. 05). In the forced swimming test, the immobility time of the F group significant increased (P<0. 01) compared with the NS group, which was decreased in the R+F group (P<0. 05). The Immunohistochemistry showed that the area of DCX positive cells in the hippocampus of the F group was downregulated compared with the NS group, which was upregulated in the R+F group. Conclusion Our findings indicate that voluntary wheel running can improve anxiety and depression-like in mice induced by formaldehyde injection, which may be related to enhanced neurogenesis in the hippocampus.

Dexmedetomidine alleviates formaldehyde induced pain by inhibiting astrocytes activation in spinal cord / 解剖学报

Objective To investigate the effect of dexmedetomidine ( DEX ) on formaldehyde-induced acute inflammatory pain. Methods Thirty female ICR mice were randomly divided into three groups, including normal saline control (NS) group, formaldehyde(F)group and dexmedetomidine + formaldehyde (DEX+F) group. 0. 1% formaldehyde solution was injected into subcutaneous tissue of mice right hind paw to establish acute inflammatory pain model. An hour before formalin injection, mice were intraperitoneal injected with DEX in DEX + F group, and mice were intraperitoneal injected with equal volume saline in NS group and F group. The expression of spinal cord glial fibrillary acidic protein ( GFAP), which is a astrocytes marker, was detected by immunohistochemistry and Western blotting. Results Spontaneous pain score showed that compared with the NS group, the F group had typical biphasic pain response ; while compared with the F group, the DEX+F group showed a significant decrease in the first (P<0. 001) and second phase pain (P<0. 001). Immunohistochemical result showed that compared with the NS group, the F group had an increase number of GFAP positive cells in the posterior horn of the spinal cord (P<0. 001). However, the DEX+F group showed a decrease number of GFAP positive cells in the posterior horn of spinal cord compared with the F group (P<0. 001 ). Western blotting result showed that compared with the NS group, the F group had increased expression of GFAP in the spinal cord (P<0. 05). Compared with the F group, the DEX + F group showed decreased GFAP expression in the spinal cord ( P < 0. 05 ). Conclusion DEX may improve formaldehyde-induced acute inflammatory pain in mice by inhibiting the activation of astrocytes in the spinal cord.