Bao Yanju, Hou Wei, Yang Liping, Liu Rui, Gao Yebo, Kong Xiangying, Shi Zhan, Li Weidong, Zheng Honggang, Jiang Shulong, Hua Baojin
Department of Oncology, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beixiange 5, Xicheng District, Beijing, 100053, China.
J Mol Neurosci. 2015 Mar;55(3):706-14. doi: 10.1007/s12031-014-0409-1. Epub 2014 Oct 26.
In an effort to understand the underlying mechanisms of cancer-induced bone pain, we investigated the presence of two protease-activated receptors, protease-activated receptor 2 (PAR2), and protease-activated receptor 4 (PAR4), in dorsal root ganglia (DRGs) neurons in an animal model of bone cancer pain. Female Wistar rats were randomized into three groups: tumor-bearing animals killed after 14 days (D14) and tumor-bearing animals killed after 21 days (D21) group and a sham operation group. After establishment of the Walker 256 carcinoma bone cancer pain model, behavioral tests were carried out to determine both the spontaneous nocifensive behavior and the paw withdrawal threshold (PWT) of mechanical and thermal hyperalgesia in these rats. Subsequently, real-time RT-PCR, Western bolt, and immunofluorescence were used to determine the messenger RNA (mRNA) and protein expression of PAR2 and PAR4 in the ipsilateral lumbar 4-5 DRG neurons. Rats in the D21 treatment group displayed a significant increase in spontaneous nocifensive behavior scores compared with the sham group as well as a considerably decreased withdrawal threshold in mechanical allodynia and thermal stimulation. Compared to sham group, the relative mRNA and protein expression of PAR2 and PAR4 was significantly upregulated in the D14 group and D21 groups, concurrent with tumor growth and proliferation. In addition, we identified the co-expression of PAR2 and PAR4 in the DRG neurons. The upregulation of mRNA and protein levels as well as the co-localization of PAR2 and PAR4 in DRG neurons suggests their novel involvement in the development and maintenance of bone cancer pain.
为了了解癌症诱发骨痛的潜在机制，我们在骨癌痛动物模型中研究了背根神经节（DRG）神经元中两种蛋白酶激活受体，即蛋白酶激活受体2（PAR2）和蛋白酶激活受体4（PAR4）的存在情况。将雌性Wistar大鼠随机分为三组：14天后处死的荷瘤动物组（D14）、21天后处死的荷瘤动物组（D21）和假手术组。在建立Walker 256癌骨癌痛模型后，进行行为测试以确定这些大鼠的自发伤害性防御行为以及机械性和热性痛觉过敏的爪撤离阈值（PWT）。随后，采用实时RT-PCR、蛋白质免疫印迹法和免疫荧光法来测定同侧腰4-5 DRG神经元中PAR2和PAR4的信使核糖核酸（mRNA）和蛋白质表达。与假手术组相比，D21治疗组大鼠的自发伤害性防御行为评分显著增加，并且在机械性异常性疼痛和热刺激中的撤离阈值显著降低。与假手术组相比，D14组和D21组中PAR2和PAR4的相对mRNA和蛋白质表达随着肿瘤生长和增殖而显著上调。此外，我们在DRG神经元中鉴定出PAR2和PAR4的共表达。DRG神经元中mRNA和蛋白质水平的上调以及PAR2和PAR4的共定位表明它们在骨癌痛的发生和维持中具有新的作用。
