The Change Of MTORC2Pathway In Amphetamine-induced Injury In Rat Striatum

ObjectiveTo explore the change of mTORC2pathway in amphetamine-induced injury inrat striatumMethodsThe animal model was established by intraperitioneal injection of amphetamine(2.5mg/kg/d), SD rats were randomly divided into control, saline and amphetaminegroups. And the amphetamine group was subdivided into1h,1d，7d，14d groups bytime of drug treatment. The rat autonomous behaviors were tested by open field,GHF-Dodd methods were used to evaluate the stereotyped behavior in rats. Thechanges of neurons and fiber in the rat striatum were observed by transmissionelectron microscope. The change of mTORC2signal in the striatum was detected bywestern blot. And the immunohistochemical method was applied to locate thedistribution of mTORC2positive neurons in the striatum.ResultsBehavioral results: The total moving distance, average speed, moving time ofthe autonomic activities in the amphetamine groups for1-14days were increasedcompared with those of the control group（p<0.01）. Moreover, stereotyped behaviorscores in amphetamine groups for7-14days were increased（p<0.01）.TEM results: The cells of the striatum in the control group showed normalstructures with intact membranes, big nucleus, circular or elliptic mitochondria withregular ridges. Nerve fibers were unbroken through transmission electron microscope.Cells and fibers of the striatum were not observed pathological changes in the salinegroup and amphetamine1d group. But the fuzzy cells, pycnosis nuclei, swellingmitochondria with disordered ridges and distorted nerve fibers were observed in thestriatum of the amphetamine14d group.Western blot results: In the striatum, P-rictor(S1219）expressions in theamphetamine1d group（p=0.013）,7d group（p=0.021）and14d group（p=0.031） were reduced compared with those in the control group; and P-AKT(T308) expressionin the amphetamine14d group was decreased (p=0.000).Immunohistochemical results: In the striatum, P-rictor(S1219）positive cellswere distributed in the CPU and LGP, and positive products of P-rictor(S1219）cellswere mainly distributed in the cytoplasm. the number of P-rictor(S1219）positive cellsin the amphetamine7d group（p=0.006）and14d group（p=0.006）were reducedcompared with those of the control group. The result was consistent with that of thewestern blot.ConclusionThe mechanism of striatum structural damage by amphetamine may beassociated with inhibition of mTORC2/AKT signaling pathway.