Synthesis Of A Novel Lithium-complex And Benefits In A Mouse Of Alzheimer’s Disease

Objective:To synthesize a novel lithium chelate（IsoLiPro）and conducting identification and structural analysis.To explore the effect of IsoLiPro on GSK-3α/β,Aβand p-tau at the cytological level;While the effects of IsoLiPro on the learning and cognitive ability,Amyloid plaque deposition,number of P-tau-positive cells and Nissl bodies were explored in the animal models of Alzheimer’s disease.Finally,the pharmacokinetics and median lethal dose of IsoLiPro were explored.Methods:1、Preparation and identification of IsoLiProIsoLiPro was prepared by single solvent crystallization,and powder X-ray diffraction,hydrogen nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy were used to identify and analyze the prepared IsoLiPro molecules.2、Molecular biology of IsoLiPro at the cellular levelThe effect of IsoLiPro at 5 m M and 10 m M concentrations on APP protein expression in SH-SY5Y/APP_SWEcells was examined by Western blotting and the effect on Aβ40 production was examined by ELISA.Western blotting was used to detect the effect of IsoLiPro（0,3.13,6.25,12.5,25 and 50 m M concentration）and lithium carbonate（Li₂CO₃）on the expression of p-GSK-3β/Total GSK-3β,p-GSK-3α/Total GSK-3α,p-tau/total tau in SH-SY5Y cells for 3 hour.3、Study of the biological function of IsoLiPro in vivo5xFAD transgenic mice were selected as an Alzheimer’s disease（AD）model for vivo experiments.The mice were divided into lithium carbonate administration group（5xFAD/Li₂CO₃,100 mg/kg）,IsoLiPro group（5xFAD/IsoLiPro,560 mg/kg）,model group（5xFAD,dd H2O）,and control group（WT,littermate-negative control）.All mice were subjected to 10 weeks of continuous gavage once a day.The corresponding solvent was administered to the wild control and model mice in the same manner.Morris water maze was used to evaluate the learning and memory abilities of 5xFAD mice.Nissl staining was used to visualize Nissl bodies in mouse brain tissue sections to observe changes in tissue morphology in the hippocampal region of mice.Immunohistochemical staining was used to measure the area of amyloid plaques and the number of p-Tau-positive cells in the hippocampus of mice.ELISA was used to detect the Aβ42/40 ratio in brain homogenates.4、Pharmacokinetic and toxicity studies of IsoLiProHorn’s method and limited trial were used to explore the half-lethal amount of lithium carbonate and IsoLiPro.SD rats were randomly divided into lithium carbonate and IsoLiPro groups,with 6 rats in each group（3 males and 3 females）.The concentration of lithium in serum and tissues was detected using ICP-MS,and pharmacokinetic parameters were calculated after gavage administration of IsoLiPro（560 mg/kg）and lithium carbonate（200 mg/kg）.Results:1、IsoLiPro was successfully synthesized with a recovery rate of 53.06%and characterized as a monoclinic crystal structure.2、IsoLiPro was found to inhibit the expression of APP protein and significantly reduce the production of Aβ40 in SH-SY5Y/APP_SWEcells（P<0.05）.IsoLiPro also increased the expression of p-GSKα/βin SH-SY5Y cells and reduced the expression of p-tau.3、In vivo experiments showed that IsoLiPro improved the learning and memory ability of 5xFAD mice,reduced amyloid deposition（P<0.05）and p-tau（P<0.05）in the brains of mice,and increased the number of neurons in the CA3 region of the hippocampus.IsoLiPro also reduced the ratio of Aβ42/Aβ40 in the brain homogenate of mice.4、The half-lethal amount of IsoLiPro was significantly higher than lithium carbonate（≤5000mg/kg vs≤1500mg/kg）,and pharmacokinetic results showed significant differences between IsoLiPro and lithium carbonate,such as a shorter clearance half-life（HL＿Lambda 10.88 h vs 60.47 h）,faster peaking time（T max 3 h vs5 h）,and lower apparent volume of distribution for IsoLiPro.Conclusions:The study demonstrated that IsoLiPro was a promising compound for the treatment of Alzheimer’s disease.It showed potential as an inhibitor of the expression of APP protein and Aβ40 production in SH-SY5Y/APP_SWEcells,as well as an enhancer of GSK-3α/βexpression and a reducer of p-tau expression.In vivo experiments using 5xFAD mice showed that IsoLiPro improved their learning and memory ability,reduced amyloid deposition and p-tau in the brain,and increased the number of neurons in the hippocampus.Moreover,IsoLiPro demonstrated lower toxicity than lithium carbonate,and its pharmacokinetic properties were superior to those of lithium carbonate.These findings provide a basis for further research and development of IsoLiPro as a potential drug for Alzheimer’s disease.