Effect of CGRP on sevoflurane-induced neurotoxicity in neonatal rats by regulating PI3K/Akt/mTOR signaling path-way

Li Tuping; Han Yi; Sun Tao; Lei Yi; Liu Zhen; Jia Liling; Zhang Linzhong

doi:10.3969/j.issn.1671-6450.2025.04.019

Abstract：Objective To investigate the effects of calcitonin gene-related peptide(CGRP)on sevoflurane-induced neurotoxicity and phosphatidylinositol 3-kinase(PI3k)/protein kinase B(Akt)/mammalian target of rapamycin(mTOR)signa-ling pathway in neonatal rats.Methods Conducted the experiment in the Anesthesia Research Laboratory of the Second Hospital of Shanxi Medical University from January 2023 to June 2024.The neonatal rat model induced by sevoflurane was constructed,the model rats were randomly divided into model group(Model group),CGRP group and CGRP+LY294002 group,with 12 rats in each group,another 12 normal rats were taken as control group(Control group).The cognitive func-tion of rats in each group were detected by Morris water maze.The level of oxidative stress was detected by enzyme-linked immunosorbent assay(ELISA).The pathological damage of brain tissue was detected by hematoxylin-eosin(HE)staining.Neuronal apoptosis was detected by terminal deoxynucleotidyl transferase mediated nick end labeling(TUNEL)staining.Through the use of immunohistochemistry,the expression of proteins associated to autophagy was found.The PI3k/Akt/mTOR signaling pathway and apoptosis-related proteins were detected by Western blot.Results The brain tissue struc-ture of the Model group was destroyed compared with Control group,the arrangement of neurons was disordered,the num-ber of neurons was reduced,the nuclear pyknosis was deeply stained,the escape latency of rats was prolonged,the resi-dence time in the target quadrant was shortened,the malondialdehyde(MDA)level and neuronal apoptosis rate,the expres-sion of B-cell lymphoma-2(Bcl-2)-related X protein(Bax)and recombinant human autophagy effector protein(Beclinl)were increased,the levels of superoxide dismutase(SOD),glutathione peroxidase(GSH-px)and the expression of Bcl-2,p62,Phosphorylated(p)-Akt/PI3k,p-Akt/Akt,p-mTOR/mTOR were decreased(P＜0.05).The brain tissue structure of CGRP group was relatively normal compared with Model group,the neurons were arranged relatively neatly,a small amount of neurons were apoptotic,the phenomenon of nuclear pyknosis was significantly reduced,the escape latency of the rats was shortened,the target quadrant residence time was prolonged,the MDA level and neuronal apoptosis rate,Bax,Beclinl ex-pression decreased,SOD,GSH-px levels and Bcl-2,p62,p-PI3k/PI3k,p-Akt/Akt,p-mTOR/mTOR expression increased(P＜0.05).The brain tissue of CGRP+LY294002 group was more severely damaged than that of CGRP group,the pathological damage of neurons was aggravated,the escape latency was prolonged,the target quadrant residence time was shortened,the MDA level and neuronal apoptosis rate,Bax,Beclin1 expression were increased,SOD,GSH-px levels and Bcl-2,p62,p-PI3K/PI3K,p-Akt/Akt,p-mTOR/mTOR expression were decreased(P＜0.05).Conclusion CGRP can reduce sevoflurane-induced neurotoxicity in neonatal rats,and its mechanism is related to the activation of PI3K/AKT/mTOR signaling pathway.