Back to Journals » Journal of Pain Research » Volume 14

Low-Dose Interleukin-2 and Regulatory T Cell Treatments Attenuate Punctate and Dynamic Mechanical Allodynia in a Mouse Model of Sciatic Nerve Injury

Authors Hu R, Zhang J, Liu X, Huang D, Cao YQ

Received 10 January 2021

Accepted for publication 13 March 2021

Published 6 April 2021 Volume 2021:14 Pages 893—906


Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 5

Editor who approved publication: Professor E. Alfonso Romero-Sandoval

Rong Hu,1– 3 Jintao Zhang,1,2,4 Xuemei Liu,1,2 Dong Huang,3 Yu-Qing Cao1,2

1Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA; 2Washington University Pain Center, Washington University School of Medicine, St. Louis, MO, USA; 3Department of Pain Management, The Third Xiangya Hospital, Central South University, Changsha, Hunan, People’s Republic of China; 4Department of Anesthesiology, Nanfang Hospital, Southern Medical University, Guangzhou, People’s Republic of China

Correspondence: Yu-Qing Cao
Department of Anesthesiology, Washington University School of Medicine, 660 South Euclid, Box 8054, St. Louis, MO, 63110, USA
Tel +1 314 362 8726
Fax +1 314 362 8334
Email [email protected]

Purpose: Nerve injury-induced mechanical hyper-sensitivity, in particular stroking-induced dynamic allodynia, is highly debilitating and difficult to treat. Previous studies indicate that the immunosuppressive regulatory T (Treg) cells modulate the magnitude of punctate mechanical allodynia resulting from sciatic nerve injury. However, whether enhancing Treg-mediated suppression attenuates dynamic allodynia is not known. In the present study, we addressed this knowledge gap by treating mice with low-dose interleukin-2 (ld-IL2) injections or adoptive transfer of Treg cells.
Methods: Female Swiss Webster mice received daily injections of ld-IL2 (1 μg/mouse, intraperitoneally) either before or after unilateral spared nerve injury (SNI). Male C57BL/6J mice received adoptive transfer of 1 x 106 Treg cells 3 weeks post-SNI. The responses to punctate and dynamic mechanical stimuli on the hindpaw were monitored before and up to 4– 6 weeks post-SNI. We also compared the distribution of Treg cells and CD3+ total T cells after SNI and/or ld-IL2 treatment.
Results: Ld-IL2 pretreatment in female Swiss Webster mice completely blocked the development of SNI-induced dynamic mechanical allodynia and reduced the magnitude of punctate allodynia. Delayed ld-IL2 treatment in female mice significantly attenuated the morphine-resistant punctate and dynamic allodynia at 3– 5 weeks post-SNI. Adoptive transfer of Treg cells to male C57BL/6J mice 3 weeks post-SNI effectively reversed the persistent punctate and dynamic allodynia, supporting that the effect of ld-IL2 is mediated through endogenous Treg cells, and is likely independent of mouse strain and sex. Neither ld-IL2 treatment nor Treg transfer affected the basal responses to punctate or brush stimuli. Ld-IL2 significantly increased the frequency of Treg cells among total CD3+ T cells in the injured sciatic nerves but not in the uninjured nerves or the dorsal root ganglia, suggesting the injured nerve as ld-IL2’s site of action.
Conclusion: Collectively, results from the present study supports Treg as a cellular target and ld-IL2 as a potential therapeutic option for nerve injury-induced persistent punctate and dynamic mechanical allodynia.

Keywords: spared nerve injury, chronic pain, punctate allodynia, dynamic allodynia, low-dose interleukin-2, regulatory T cell

Creative Commons License This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at and incorporate the Creative Commons Attribution - Non Commercial (unported, v3.0) License. By accessing the work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. For permission for commercial use of this work, please see paragraphs 4.2 and 5 of our Terms.

Download Article [PDF]  View Full Text [HTML][Machine readable]