Effects Of Triptolide On Astrocytes And Cholinergic Fibers After Microinjection Of Beta-amyloid Protein Into Cerebral Cortex In Rats

Objective:To explore the effects of triptolide(TP) on astrocytes and cholinergic fibers after microinjection of beta-amyloid protein(Aβ) into cerebral cortex in rats.Methods:1.Fifteen male SD rats were equally divided into control group, Aβgroup and TP-treated group. The Aβgroup was made with bilateral microinjection of aggregated Aβ1-40 into cerebral cortex in rats and the control group rats were injected with normal saline in the same way. The TP-treated group rats were administered TP(0.4mg/kg.d) intraperitoneally after microinjection of aggregated Aβ1-40 into cerebral cortex for 15d.2.The structural changes of cerebral cortex near the injected site in each group was assayed by Toluidine Blue staining.3.The expression of astrocytes in cerebral cortex of each group was assayed by GFAP immunohistochemical staining.4.The expression of cholinergic fibers in cerebral cortex of each group was assayed by AChE histochemical staining.Results:1.Toluidine Blue staining results showed that a few proliferous neuroglial cells in cerebral cortex near the injected site were seen in the control group,and a great deal of neuronal loss and a large amount of proliferous neuroglial cells in cerebral cortex near the injected site were seen in the Aβgroup,and the number of proliferous neuroglial cells and neuronal damage in cerebral cortex near the injected site were reduced in the TP-treated group.2.Immunohistochemically , the number,average area and average optical density of astrocytes in cerebral cortex of the Aβgroup were obviously increased as compared with the control group.The number,average area and average optical density of astrocytes in cerebral cortex of the TP-treated group were obviously decreased as compared with the Aβgroup.3.AChE histochemical staining results showed that the density of cholinergic fibers in cerebral cortex of the Aβgroup were obviously decreased as compared with the control group, and the density of cholinergic fibers in cerebral cortex of the TP-treated group were obviously increased as compared with the Aβgroup.Conclusions:TP can inhibit astrocytic activation induced by Aβand alleviate damages of cholinergic fibers induced by Aβ.