重复高＋Gz暴露后大鼠三叉神经脊束核尾侧亚核与三叉神经节内神经活性物质基因表达

Neuroactive substances gene expression changes in spinal trigeminal nucleus caudalis nucleus and trigeminal ganglia of rats by the exposure of repeated high ＋Gz

目的 研究重复高＋Gz暴露后,大鼠三叉神经脊束核尾侧亚核（spinal trigeminal nucleus caudalis,SpVc）内P物质（substance P）与N-甲基-D-天冬氨酸受体（N-methyl-D-aspartate receptor antagonists,NMDAR）,以及三叉神经节（trigeminal ganglion,TG）内前速激肽原A（preprotachykinin A,PPTA）、β降钙素基因相关肽（β-calcitonin-gene-related peptide,β-CGRP）、与钠通道PN3、NaN的mRNA表达情况,探讨重复＋Gz引起颞颌关节疼痛的原因与机制. 方法 雄性SD大鼠36只,体重200～300 g.按随机数字表法平均分成3组：对照组、＋5Gz组、＋10 Gz组.将各组大鼠分别固定于动物离心机转臂末端的固定装置上,并使之呈俯卧位,头朝向转臂轴心.离心机转臂半径为1 m.G值增长率1 G/s、峰值持续时间30 s,每天连续离心5次,2次之间间隔60 s,每周4d,共持续3周.＋5Gz组暴露峰值为＋5Gz;＋10 Gz组暴露峰值为＋10 Gz;对照组按上述相同时间和频次在离心机上静止固定.取大鼠TG与SpVc,提取RNA,荧光定量RT-PCR法检测P物质、NMDAR、PPTA、β-CGRP、PN3与NaN的mRNA表达变化. 结果 ①重复＋Gz暴露后大鼠TG内PPTA、β-CGRP、PN3及NaN基因的mRNA相对表达量明显增高,组间差异有统计学意义（F=329～1 030,P＜0.01）,且与＋Gz值成正比.②大鼠SpVc内P物质与NMDAR的mRNA相对表达量明显增高,组间差异有统计学意义（F=408、1 062,P＜0.01）,且与＋Gz值成正比. 结论 在重复高＋Gz环境下,初级感觉神经元的生化特征发生了显著变化;神经活性物质在颞下颌关节疾病引起的疼痛传导中发挥了作用,与颞颌关节疼痛的外周及中枢的传导作用机制相关.

Objective To study the mRNA expression of substance P （SP）,N-methyl-D-aspartate receptor antagonists （NMDAR） in rat＆#39;s spinal trigeminal nucleus caudalis （SpVc） and preprotachykinin A （PPTA）,β-calcitonin-gene-related peptide （β-CGRP）,sodium channel （PN3）,and to investigate the cause and mechanism of repeated high ＋ Gz induced temporomandibular joint pain.Methods Thirty-six male SD rats （weight 200-300 g） were randomly divided into control,＋5 Gz and ＋10 Gz groups.Rats in each group were respectively fixed at the end of animal centrifuge arm with prone position.Head was towards to the rotating center.The radius of the centrifuge is 1 m.＋Gz pulses were applied on rats with 1 G/s onset rate for 30 s plateau duration.The centrifuge tests were done 5 times a day with 60 s intervals,4 days a week for 3 weeks.The ＋5 Gz and ＋10 Gz group was respectively exposed to ＋ 5 Gz and ＋10 Gz peak.The control group was only fixed on centrifuge along with the test schedule but without centrifuge running.RNA was collected from TG and SpVc of rats.Fluorescent quantitative RT-PCR method was used to detect mRNA of SP,NMDAR,PPTA,β-CGRP,PN3 and NaN mRNA expression.Results ① Repeated high acceleration （＋ Gz） exposure caused PPTA,β-CGRP,PN3 and NaN gene expression significantly increased in rats＆#39; TG.Differences among groups showed statistical significance （F=329-1 030,P〈 0.01）.The differences were in direct proportion to ＋Gz value.②The mRNA relative expressions of SP and MMDAR were significantly increased in rats＆#39; SpVc and the difference among groups was statistical significance （F=408,1 062,P〈 0.01）,and was in direct proportion to ＋ Gz value.Conclusions Under repeated high acceleration （＋ Gz）,the biochemical characteristics of primary sensory neurons occur significant change.Nerve active substances play a role in the pain transmission caused by temporomandibular joint disease,which is related to the peripheral and central conduction mechanism of temporomandibular joint pain.