Yoshino Kensuke, Suzuki Miyako, Kawarai Yuya, Sakuma Yoshihiro, Inoue Gen, Orita Sumihisa, Yamauchi Kazuyo, Aoki Yasuchika, Ishikawa Tetsuhiro, Miyagi Masayuki, Kamoda Hiroto, Kubota Gou, Oikawa Yasuhiro, Inage Kazuhide, Sainoh Takeshi, Sato Jun, Nakamura Junichi, Toyone Tomoaki, Takahashi Kazuhisa, Ohtori Seiji
Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
Yonsei Med J. 2014 Nov;55(6):1600-5. doi: 10.3349/ymj.2014.55.6.1600.
Transient receptor potential vanilloid 1 (TRPV1) is a ligand-gated nonselective cation channel, which can be activated by capsaicin and other noxious stimuli. Recently, an association between bone pain and TRPV1 has been reported. However, the influence of osteoporosis on TRPV1 in the sensory system innervating the femur has not been reported.
TRPV1-immunoreactive (ir) in dorsal root ganglia (DRG) neurons labeled with neurotracer [Fluoro-Gold (FG)] innervating the femurs of Sprague Dawley rats were examined in control, sham, and ovariectomized (OVX) rats. We evaluated osteoporosis in the femurs and compared the proportion of TRPV1-ir DRG neurons innervating femur between the 3 groups of rats.
OVX rats showed osteoporotic cancellous bone in the femur. FG labeled neurons were distributed from L1 to L6 DRG, but there was no significant difference in the proportion of labeled neurons between the 3 groups (p>0.05). The proportions of FG labeled TRPV1-ir DRG neurons were 1.7%, 1.7%, and 2.8% of DRG neurons innervating the femur, in control, sham-operated, and OVX rats, respectively. The proportion of TRPV1-ir neurons in DRG innervating the femur in OVX rats was significantly higher than that in control and sham-operated rats (p<0.05).
Under physiological conditions, DRG neurons innervating femurs in rats contain TRPV1. Osteoporosis increases the numbers of TRPV1-ir neurons in DRG innervating osteoporotic femurs in rats. These findings suggest that TRPV1 may have a role in sensory perception of osteoporotic femurs.
瞬时受体电位香草酸亚型1（TRPV1）是一种配体门控的非选择性阳离子通道，可被辣椒素和其他有害刺激激活。最近，有报道称骨痛与TRPV1之间存在关联。然而，骨质疏松症对支配股骨的感觉系统中TRPV1的影响尚未见报道。
在对照、假手术和去卵巢（OVX）大鼠中，检查用神经示踪剂[荧光金（FG）]标记的支配Sprague Dawley大鼠股骨的背根神经节（DRG）神经元中的TRPV1免疫反应性（ir）。我们评估了股骨的骨质疏松情况，并比较了三组大鼠中支配股骨的TRPV1-ir DRG神经元的比例。
OVX大鼠股骨出现骨质疏松性松质骨。FG标记的神经元分布于L1至L6 DRG，但三组之间标记神经元的比例无显著差异（p>0.05）。在对照、假手术和OVX大鼠中，FG标记的TRPV1-ir DRG神经元分别占支配股骨的DRG神经元的1.7%、1.7%和2.8%。OVX大鼠中支配股骨的DRG中TRPV1-ir神经元的比例显著高于对照和假手术大鼠（p<0.05）。
在生理条件下，大鼠中支配股骨的DRG神经元含有TRPV1。骨质疏松症增加了大鼠中支配骨质疏松性股骨的DRG中TRPV1-ir神经元的数量。这些发现表明TRPV1可能在骨质疏松性股骨的感觉感知中起作用。
