<p style="text-align: center;">LU Yuan, GU Muen, LI Han, HUANG Yan, ZHOU Cili, WU Huangan, DONG Yongzheng, SHI Zheng, DING Guanghong, BAO Chunhui, FENG Xiaoming, WU Luyi</p><p style="text-align: center;">(1.&nbsp; Department&nbsp; of&nbsp; Mechanics&nbsp; and&nbsp; Engineering&nbsp; Science,&nbsp; Fudan&nbsp; University.&nbsp; Shanghai&nbsp; 200433,&nbsp; China.;&nbsp; 2.Shanghai&nbsp; Institute&nbsp; of&nbsp; Acupuncture-Moxibustion&nbsp; and&nbsp; Meridian.&nbsp; Shanghai&nbsp; 200030,&nbsp; China.;&nbsp; 3.&nbsp; Shanghai University of Traditional Chinese Medicine. Shanghai&nbsp; 201203, China.;&nbsp; 4. Shanghai Qigong&nbsp; Research Institute,&nbsp;</p><p style="text-align: center;">Shanghai University of Traditional Chinese Medicine, Shanghai 200030, China.)</p><p style="text-align: justify;"><strong>Abstract</strong>:&nbsp;<strong> Objective</strong>:&nbsp; To&nbsp; further&nbsp; explore&nbsp; the&nbsp; mechanisms&nbsp; of&nbsp; warming&nbsp; moxibustion&nbsp; on&nbsp; irritable&nbsp; bowel syndrome (IBS). Methods: 24 male Sprague-Dawley (SD) rats were randomly divided into 3 groups: normal group, IBS group, and warming moxibustion group (WM group). Rats in the WM group received moxibustion at&nbsp; Tianshu&nbsp; acupoints&nbsp; (ST25)&nbsp; for&nbsp; 20&nbsp; min&nbsp; once&nbsp; per&nbsp; day.&nbsp; A&nbsp; total&nbsp; of&nbsp; 7&nbsp; treatments&nbsp; were&nbsp; performed.&nbsp; The abdominal&nbsp; withdrawal&nbsp; reflex&nbsp; (AWR)&nbsp; scores&nbsp; were&nbsp; recorded.&nbsp; The&nbsp; expression&nbsp; of&nbsp; prepro-orexin&nbsp; and&nbsp; orexin receptor&nbsp; 2&nbsp; (OX2R)&nbsp; in&nbsp; the&nbsp; colon&nbsp; and&nbsp; cerebral&nbsp; cortex&nbsp; was&nbsp; examined&nbsp; using&nbsp; in&nbsp; situ&nbsp; hybridization&nbsp; (ISH)&nbsp; and immunohistochemical detection.<strong> Results</strong>: Compared with the normal group, the IBS group had higher AWR scores (P&lt;0.01) while the scores were lower in the WM group than IBS group (P&lt;0.05). ISH assays showed that the expression of prepro-orexin and OX2R mRNA in the cerebral cortex and colon was reduced in the IBS group compared to the normal group (P&lt;0.01), and was increased in the WM group compared to the IBS group (P&lt;0.01). The immunohistochemical results were consistent with the ISH. Conclusion: The effect of improving visceral hypersensitivity by warming moxibustion may be associated with the up-regulation of abnormally reduced expression of prepro-orexin and OX2R in the colon and cerebral cortex.&nbsp;</p><p style="text-align: justify;"><strong>Key words:</strong>&nbsp; Acupuncture and moxibustion, Irritable bowel syndrome, warming moxibustion, prepro-orexin, OX2R&nbsp;</p><p><br/></p>