Effect of moxibustion on Nogo/neurotrophin receptor signaling pathway in rats with cerebral ischemia/reperfusion injury

Abstract

To observe the effect of moxibustion treatment on the expression of Nogo-A, Nogo receptor (NgR), neurotrophin receptor p75 (p75NTR) and leucine rich repeat and Ig domain containing 1 (Lingo-1) in brain tissue of rats with cerebral ischemia/reperfusion injury (CI/RI), so as to analyze its mechanism underlying improvement of CI/RI. Male SD rats were randomly divided into sham operation group (16 rats), model group (17 rats), NEP1-40 (extracellular peptide residues 1-40, a blocker targeting NgR) group (model+blocker, 17 rats) and moxibustion group (model+moxibustion, 17 rats). The CI/RI model was established by occlusion of the left middle cerebral artery (MCAO). Moxibustion was applied to "Baihui"(GV20), right "Quchi"(LI11) and "Zusanli"(ST36) for 20 min, once a day for 14 days, with 2 days' rest after the top 7 days' intervention. For rats of the NEP1-40 group, 30 μL PBS containing 18 μg NEP 1-40 was injected into the epidural inferior vena (L5-S1) via a polyvinyl chloride conduit. The neurological deficit state in each group was evaluated by Longa's 5-point scale and Feeney's 7-point scale of beam walking test (BWT). The cerebral infarct volume was assessed by 2,3,5-triphenyltetrazole chloride staining. The brain tissue between the central anterior and posterior sulcus was taken for observing the expression of NgR and Lingo-1 by fluorescence double-label method, and for determining the expression levels of Nogo-A, NgR, p75NTR and Lingo-1 mRNAs and proteins by real-time quantitative PCR and Western blot, respectively. After modeling, the Longa's score, infarct volu-me percent, expression levels of Nogo-A, NgR, Lingo-1 and p75NTR mRNAs and proteins were significantly increased (P<0.01) and BWT score was obviously decreased (P<0.01) in the model group relevant to the sham operation group. In comparison with the model group, the increase of Longa's score, infarct volume percentage, expression levels of Nogo-A, NgR, Lingo-1 and p75NTR mRNAs and proteins and decrease of BWT score in NEP1-40 and moxibustion groups were reversed (P<0.01) except Nogo-A protein in the NEP1-40 group. The effect of moxibustion was significantly superior to that of blocker NEP1-40 in redu-cing the infarct volume percentage, and down-regulating the expression of Nogo-A mRNA and protein, p75NTR mRNA and protein, NgR and Lingo-1 proteins (P<0.01, P<0.05). Moxibustion, similar to blocker NEP1-40 of NgR, can improve neurological dysfunction in CI/RI rats, which may be related to its functions in reducing cerebral infarction and down-regulating the activity of Nogo/neurotrophin receptor signaling pathway.