Department of Physical Medicine & Rehabilitation, Qilu Hospital, Shandong University, Jinan, 250012, China.
Department of Orthopedics, Qilu Hospital, Shandong University, Jinan 250012, China.
Neurosci Lett. 2020 Jan 18;716:134630. doi: 10.1016/j.neulet.2019.134630. Epub 2019 Nov 29.
The aim of this study was to investigate the effects of aquaporin 1 (AQP1) knockdown on allodynia in rats with chronic compression of the dorsal root ganglia (DRG) and the role of TRPV4 in these effects.
Adult male Wistar rats were subjected to chronic compression of the dorsal root ganglia (CCD) via surgery. Behavioral tests were performed to calculate the paw withdrawal mechanical threshold (PWMT). Gene silence was induced by injecting rats with lentivirus expressing AQP1 short hairpin RNA (shRNA, Lv-shAQP1). Western blot analyses were performed to examine AQP1 and TRPV4 protein expression. The concentration of cyclic guanosine monophosphate (cGMP) was determined via enzyme-linked immunosorbent assay.
AQP1 protein levels in DRG neurons were significantly increased in CCD rats and were accompanied by a decrease in the PWMT. Lentivirus-mediated RNA interference of AQP1 decreased AQP1 protein expression in CCD rats and normalized their PWMT, but not in rats infected with lentivirus-expressing negative control short hairpin RNA. Furthermore, AQP1 was identified as a cGMP-gated channel. cGMP concentration was upregulated in CCD rats. This effect was attenuated by treatment with a cGMP inhibitor. Additionally, the cGMP inhibitor decreased the mechanical allodynia and AQP1 protein expression in CCD rats. Finally, levels of TRPV4 expression were upregulated in DRG neurons and the L4/L5 spinal cord following surgery, and these effects were reversed by treatment with Lv-shAQP1 or a cGMP inhibitor.
AQP1 plays a vital role in CCD-induced allodynia as Lv-shAQP1 significantly reduced the allodynia in CCD rats by inhibiting TRPV4 expression.
本研究旨在探讨水通道蛋白 1（AQP1）敲低对慢性压迫背根神经节（DRG）大鼠痛觉过敏的影响，以及 TRPV4 在这些影响中的作用。
成年雄性 Wistar 大鼠通过手术接受慢性压迫背根神经节（CCD）。通过计算爪撤回机械阈值（PWMT）进行行为测试。通过注射表达 AQP1 短发夹 RNA（shRNA，Lv-shAQP1）的慢病毒诱导基因沉默。通过 Western blot 分析检测 AQP1 和 TRPV4 蛋白表达。通过酶联免疫吸附试验测定环鸟苷酸（cGMP）的浓度。
DRG 神经元中 AQP1 蛋白水平在 CCD 大鼠中显著增加，同时 PWMT 降低。慢病毒介导的 AQP1 RNA 干扰降低了 CCD 大鼠中 AQP1 蛋白的表达，并使 PWMT 正常化，但在感染表达阴性对照短发夹 RNA 的慢病毒的大鼠中则没有。此外，AQP1 被鉴定为 cGMP 门控通道。CCD 大鼠中 cGMP 浓度升高。用 cGMP 抑制剂处理可减弱该效应。此外，cGMP 抑制剂降低了 CCD 大鼠的机械性痛觉过敏和 AQP1 蛋白表达。最后，手术后 DRG 神经元和 L4/L5 脊髓中 TRPV4 表达上调，Lv-shAQP1 或 cGMP 抑制剂处理可逆转这些效应。
AQP1 在 CCD 诱导的痛觉过敏中起重要作用，因为 Lv-shAQP1 通过抑制 TRPV4 表达显著减轻 CCD 大鼠的痛觉过敏。
