Department of Physiology, Nihon University School of Dentistry, Tokyo, 101-8310, Japan.
Faculty of Dental Science, Department of Aging Science and Pharmacology, Kyushu University, Fukuoka, 812-8582, Japan.
Sci Rep. 2021 Oct 8;11(1):20053. doi: 10.1038/s41598-021-99585-2.
The effects of stem cells from human exfoliated deciduous teeth (SHED) on mechanical allodynia were examined in mice. A single intravenous injection of SHED and conditioned medium from SHED (SHED-CM) through the left external jugular vein significantly reversed the established mechanical allodynia induced by spinal nerve transection at 6 days after injection. SHED or SHED-CM significantly decreased the mean numbers of activating transcription factor 3-positive neurons and macrophages in the ipsilateral side of the dorsal root ganglion (DRG) at 20 days after spinal nerve transection. SHED or SHED-CM also suppressed activation of microglia and astrocytes in the ipsilateral side of the dorsal spinal cord. A single intravenous injection of secreted ectodomain of sialic acid-binding Ig-like lectin-9 and monocyte chemoattractant protein-1 had no effect on the established mechanical allodynia, whereas a single intravenous injection of protein component(s) contained in SHED-CM with molecular weight of between 30 and 50 kDa reversed the pain. Therefore, it may be concluded that protein component(s) with molecular mass of 30-50 kDa secreted by SHED could protect and/or repair DRG neurons damaged by nerve transection, thereby ameliorating mechanical allodynia.
研究了人脱落乳牙干细胞（SHED）对机械性痛觉过敏的影响。通过左侧颈外静脉单次静脉注射 SHED 和 SHED 条件培养基（SHED-CM），可显著逆转注射后 6 天脊髓神经横断引起的机械性痛觉过敏。SHED 或 SHED-CM 可显著减少脊髓神经横断后 20 天同侧背根神经节（DRG）中激活转录因子 3 阳性神经元和巨噬细胞的平均数量。SHED 或 SHED-CM 还可抑制同侧背侧脊髓中小胶质细胞和星形胶质细胞的激活。单次静脉注射唾液酸结合免疫球蛋白样凝集素 9 的分泌型外结构域和单核细胞趋化蛋白 1 对已建立的机械性痛觉过敏没有影响，而 SHED-CM 中分子量在 30 至 50 kDa 之间的蛋白质成分可逆转疼痛。因此，可以得出结论，SHED 分泌的分子量为 30-50 kDa 的蛋白质成分可以保护和/或修复神经横断损伤的 DRG 神经元，从而改善机械性痛觉过敏。
