Topical Application of L-theanine Relieves Mouse Psoriasis Pruritus by Inhibiting Abnormal Growth of Skin Nerve Endings
- VernacularTitle:L-茶氨酸局部给药抑制皮肤神经末梢的异常生长缓解小鼠银屑病瘙痒
- Author:
Ying-tao JIE
1
;
Zhen-jia LIN
1
;
Jun ZHANG
1
;
Zhi TAN
1
;
Ya-nan XU
1
;
Ying XIONG
1
;
Yuan TANG
1
;
Li-jun ZHOU
1
Author Information
1. Department of Physiology， Zhongshan School of Medical， Sun Yat-sen University//Center for Pain Research， Sun Yat-sen University， Guangzhou 510080， China
- Publication Type:Journal Article
- Keywords:
psoriasis;
pruritus;
L-theanine;
TNF-α;
abnormal growth of nerve endings
- From:
Journal of Sun Yat-sen University(Medical Sciences)
2021;42(2):161-170
- CountryChina
- Language:Chinese
-
Abstract:
ObjectiveTo investigate whether L-theanine exerts anti-pruritic effect on mice with imiquimod （IMQ）-induced psoriasis and its related mechanisms. MethodsWe established the psoriasis model by applying the IMQ ointment topically on mice back skin and oral （10 mg/kg∙d） or topical pretreatment （50， 125， 250 mmol/L， twice one day） of L-theanine was used as the treatment. Spontaneous behavior， such as scratching， was used to detect the therapeutic effect. Immunofluorescence （IF）， Western Blot （WB） and primary dorsal root ganglion （DRG） neuronal culture were used to investigate the mechanisms. ResultsOral administration of L-theanine had no apparent effect on IMQ-induced pruritus， but topical delivery in the lesional skin significantly improved the spontaneous behavior such as licking or biting and flinching in a dose-dependent manner. IF and WB results showed that L-theanine not only inhibited the overexpression of TNF-α in model mouse skin， but also prevented the abnormal growth of β3-tubulin+ nerve fibers and the upregulation of transient receptor potential vanilloid 1 （TRPV1）， an itch-related molecule. Moreover， the results from the experiments with primary cultured DRG neurons further confirmed that L-theanine directly reduced IMQ-induced abnormal outgrowth of CGRP+， β3-tubulin+ neurites in a concentration dependent manner. ConclusionsTopical application of L-theanine can relieve pruritus or discomfort in IMQ-induced psoriasis mouse model by inhibiting abnormal growth of skin nerve fiber endings. Therefore， L-theanine could be a potential treatment for chronic itch in psoriasis.
