Post-Graduate Program in Medical Sciences, School of Medicine, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.
Laboratory of Pain & Neuromodulation at UFRGS, Porto Alegre, Brazil.
Pain Med. 2020 Oct 1;21(10):2271-2279. doi: 10.1093/pm/pnaa027.
We investigated sex differences and the influence of brain-derived neurotrophic factor (BDNF) in the descending pain modulatory system (DPMS), as measured by change on the numerical pain scale (NPS; 0-10) during conditioned pain modulation (CPM task; primary outcome) and by function of the corticospinal motor pathway and heat pain thresholds (HPTs; secondary outcomes).
This cross-sectional study included healthy volunteers ranging in age from 18 to 45 years (32 male and 24 female). Assessment included serum BDNF, HPT, change on the NPS (0-10) during the CPM task, and motor-evoked potential (MEP) using transcranial magnetic stimulation (TMS).
The MEP (Mv) amplitude was larger in male participants compared with female participants (mean [SE] = 1.55 [0.34] vs mean [SE] = 1.27 [0.27], respectively, P = 0.001). The mean NPS (0-10) during CPM task changed more substantially for female compared with male participants (mean [SE] = -3.25 [2.01] vs mean [SE] = -2.29 [1.34], respectively, P = 0.040). In addition, a higher serum BDNF (adjusted index for age) was associated with a larger decrease of the NPS during CPM task (P = 0.003), although further regression analyses by sex showed that this was only significant for females (P = 0.010).
Significant sex differences were identified in DPMS function and corticospinal motor pathway integrity. Nevertheless, BDNF was associated with the function of the DPMS in female but not male participants, indicating that sex and neuroplasticity state are crucial factors for pain perception in healthy subjects.
我们通过条件性疼痛调制（CPM 任务）期间数字疼痛量表（NPS；0-10）的变化（主要结局）和皮质脊髓运动通路和热痛阈值（HPT；次要结局）的功能，研究性别差异和脑源性神经营养因子（BDNF）在下行疼痛调制系统（DPMS）中的影响。
本横断面研究纳入了年龄在 18 至 45 岁之间的健康志愿者（32 名男性和 24 名女性）。评估包括血清 BDNF、HPT、CPM 任务期间 NPS（0-10）的变化以及使用经颅磁刺激（TMS）的运动诱发电位（MEP）。
与女性参与者相比，男性参与者的 MEP（Mv）振幅更大（分别为 1.55 [0.34] 和 1.27 [0.27]，P=0.001）。CPM 任务期间 NPS（0-10）的平均值变化在女性参与者中比男性参与者更大（分别为-3.25 [2.01] 和-2.29 [1.34]，P=0.040）。此外，较高的血清 BDNF（年龄调整指数）与 CPM 任务期间 NPS 的较大下降相关（P=0.003），尽管按性别进行的进一步回归分析显示，这仅在女性中显著（P=0.010）。
DPMS 功能和皮质脊髓运动通路完整性存在显著性别差异。然而，BDNF 与女性参与者而不是男性参与者的 DPMS 功能相关，表明性别和神经可塑性状态是健康受试者疼痛感知的关键因素。
