Remodeling of myelinated fibers and internal capillaries in distal peripheral nerves following aerobic exercise in aged rats
Remodeling of myelinated fibers and internal capillaries in distal peripheral nerves following aerobic exercise in aged rats
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DOI：
10.1152/japplphysiol.00257.2018
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发表时间：
2018-10-01
影响因子：
3.3
通讯作者：
Kumagai, Shuzo
中科院分区：
文献类型：
--
作者：
Sakita, Masahiro;Murakami, Shinichiro;Kumagai, Shuzo
本研究的目的是确定老年有氧运动（AE）是否有助于改善周围神经和毛细血管中有髓纤维（MF）的形态。此外，我们研究了这些过程是否与循环血液和周围神经组织中脑源性神经营养因子（BDNF）和血管内皮生长因子（VEGF）的互补活性有关。 14 只雄性 Wistar 大鼠（年龄：95 周）被随机分为中度 AE（n = 8）组和久坐组（SED；n = 6）。 AE组大鼠每天进行跑步机跑步1 h，持续2周，随后摘除两组大鼠双侧胫神经，检查MF和毛细血管结构。通过酶联免疫吸附测定分析血清和周围神经中 BDNF 和 VEGF 的水平。 AE 组的髓鞘厚度、轴突直径和毛细血管管腔直径显着大于 SED 组（P < 0.0001）。 AE组血清BDNF和VEGF水平分别显着低于SED组和SED组（P < 0.001）。相反，AE 组胫神经组织中 BDNF 和 VEGF 水平分别显着高于 SED 组（P < 0.001）。总之，我们的研究表明，定期 AE 可能会通过涉及 BDNF 和 VEGF 的互补过程，诱导老年周围神经毛细血管扩张并增厚髓磷脂。新的和值得注意的越来越多的证据表明，与年龄相关的肌少症伴随着周围神经中有髓纤维 (MF) 的变性。我们的研究表明，定期有氧运动有助于增加 MF 周围髓磷脂的厚度和扩大毛细血管，这可能是通过涉及脑源性神经营养因子和血管内皮生长因子的互补过程来实现的。我们的研究结果表明，定期、中等强度的有氧运动可能有助于预防和逆转老年人周围神经退化。
The aim of this study was to determine whether aerobic exercise (AE) in old age contributes to improving the morphologies of myelinated fibers (MFs) in peripheral nerves as well as capillaries. Furthermore, we investigated whether such processes are associated with complementary activity of brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) in the circulating blood and peripheral nerve tissue. Fourteen male Wistar rats (age: 95 wk) were randomly divided into moderate AE (n = 8) and sedentary (SED; n = 6) groups. Rats in the AE group performed treadmill running for 1 h per day for 2 wk, following which the bilateral tibial nerves of the two groups were removed to examine MF and capillary structure. Levels of BDNF and VEGF in the serum and peripheral nerves were analyzed via enzyme-linked immunosorbent assay. Myelin thickness, axon diameter, and capillary luminal diameter were significantly larger in the AE group than in the SED group (P < 0.0001). Levels of serum BDNF and VEGF were significantly lower and higher, respectively, in the AE group than in the SED group (P < 0.001). Conversely, BDNF and VEGF levels in tibial nerve tissue were significantly higher, respectively, and lower in the AE group than in the SED group (P < 0.001). In conclusion, our study indicates that regular AE induces enlargement of the capillaries and thickens the myelin in aged peripheral nerves, likely via a complementary process involving BDNF and VEGF.NEW & NOTEWORTHY Accumulating evidence indicates that age-related sarcopenia is accompanied by the degeneration of myelinated fibers (MFs) in peripheral nerves. Our study indicates that regular aerobic exercise contributes to increased thickness of the myelin surrounding MFs and enlargement of the capillaries, likely via a complementary process involving brain-derived neurotrophic factor and vascular endothelial growth factor. Our findings demonstrate that regular, moderate-intensity aerobic exercise may help to prevent and reverse peripheral nerve regression in older adults.