Research In The Protective Effect Of Chitosan-trolox Nanoparticles Against Oxidative Stress Injury Induced By H₂O₂ In SH-SY5Y Cell

Arzheimer’s Disease（AD） is a common neurodegenerative disorder characterized by extracellular plaques of amyloid-β（Aβ）, neurofibrillary tangles of tau protein, and loss of memory. Although the underlying biochemical and molecular mechanisms leading to neuronal degeneration in AD remains unclear, oxidative stress is closely related to the pathogenesis of AD. As a kind of new carrier materail,nanomaterials have many advantages such as non-toxic, small size,non-immunogenicity. Nanoparticles can provide new ideas for treatment of nerve injury diseases such as AD through passing the blood-brain barrier.Therefore, we used non-toxic chitosan as raw materials to load Trolox（water-soluble vitamin E） and prepared Chitosan-Trolox Nanoparticles（CS-Trolox NPs）. SHSY5Y/APPsw cells induced by H₂O₂ as a cell model of AD to mimic oxidative stress injury and studied the protection effects and mechanism of CS-Trolox NPs on oxidative damage. The specific findings are just as followings:1.Studies on preparation, characterization and biocompatibility of CS-Trolox NPsChitosan with low molecular weight from high molecular weight was got t hrough using H₂O₂ and mechanical ultrasonic as the methods of oxidative degr adation. And then, Epoxy ethane was added into chitosan solution to modify c hitosan with hydroxyethyl group, then antioxidant Trolox wrapped in CS NPs prepared by self-assembly. The results of TEM showed that the sizes of unifor m sized CS NPs were about 30 nm. The size of CS-Trolox NPs was bigger th an CS NPs, showing that Trolox was successfully loaded. High concentrations（1mg/m L） of NPs exposed to cells 24 h still does not produce significant cytoto xicity, proving the NPs have good biocompatibility. Spectroscopy results show that Trolox within the CS NPs increased 27-fold in aqueous solution than Trol ox monomer, reflecting its excellent bioavailability and the high-loading efficien cy of the nanoparticles on the small molecules.2.Establishing oxidative damage model of SHSY5Y/APPsw cells induced by H₂O₂ as a cell model of ADWe used H₂O₂ to treat SHSY5Y/APPsw cells in order to simulate the oxidative stress injury of nerves to set the cell model of AD. Comprehensive the suppression effect, we selected 80μM H₂O₂ treatment for 6h as the injury conditions for the subsequent drug protection experiments.3.Protective effects of CS-Trolox NPs on nerve oxidative damage induced by H₂O₂Treatment with the CS-Trolox NPs for 48 h showed obvious protection effects to SHSY5Y/APPsw cells under oxidative stress injury compared with Trolox monomer.Especially in improving cell viability and cell morphological, reducing apoptotic and necrotic death, the level of intracellular ROS, also inhibiting the increase of Bax/Bcl-2ratio which open the mitochondrial apoptosis pathway, and reducing the activation of caspase-3 protein and its substrate PARP.