Objective:To explore the effect of pentraxin 3 (PTX3) on memory improvement and Aβ expression in Alzheimer's disease (AD) model mice.Methods:(1) Ten 5-month-old 5×FAD mice were randomly divided into PTX3 group and model group ( n=5); 5 C57BL/6 wild-type mice at the same age were selected as control group; mice in the PTX3 group and control group were stereotactically injected 4 μL 0.5 g/L PTX3 or same dose of phosphate buffered saline (PBS); Morris water maze test was used to detect the learning and memory abilities, Y maze test was used to detect the short-term memory, and ELISA was used to obsevre the contents of Aβ 40 and Aβ 42 in the brain hemisphere. (2) Twenty-five 3-month-old 5×FAD mice were randomly divided into model group, 2 μg/kg PTX3 group, 4 μg/kg PTX3 group, 8 μg/kg PTX3 group, and 16 μg/kg PTX3 group ( n=5); 5 C57BL/6 wild-type mice at the same age were selected as control group; mice in the PTX3 groups were intranasally injected 2, 4, 8, and 16 μg/kg PTX3, respectively; those in the model group and control group were intranasally injected same dose of PBS; injection was given once every 96 h for a total of 7 times. Morris water maze test was used to detect the learning and memory abilities, Y maze test was used to detect the short-term memory, and ELISA was used to obsevre the contents of Aβ 40 and Aβ 42 in the hippocampus. Results:(1) Compared with the model group, the PTX3 group had significantly shorter platform latency, higher percentage of exploration time and higher percentage of spontaneous alternations ( P<0.05). Compared with those in model group ([63.38±21.42] pg/mL, [29.77±6.11] pg/mL), the concentrations of Aβ 40 and Aβ 42 in the brain tissues of PTX3 group ([15.87±2.11] pg/mL, [16.55±1.95] pg/mL) were statistically lower ( P<0.05). (2) Compared with the model group, the 16 μg/kg PTX3 group had significantly shorter escape latency and higher percentage of exploration time ( P<0.05); compared with the model group, the 2 μg/kg PTX3 group and 16 μg/kg PTX3 group had significantly higher percentage of spontaneous alternations ( P<0.05). The contents of Aβ 40 and Aβ 42 in the hippocampus of 8 μg/kg PTX3 group and 16 μg/kg PTX3 group were statistically lower compared with those in the model group ( P<0.05). Conclusion:PTX3 may attenuate cognitive deficits and decrease Aβ expression in the brain or hippocampus tissues of 5×FAD mice with AD.

Objective:To explore the pathogenesis of flunarizine-induced parkinsonism from gut-brain axis perspective.Methods:Thirty male C57BL/6 mice were randomly divided into control group and flunarizine group ( n=15). Mice in the control group were given 0.1 mL 50% polyethylene glycol 400+50% saline by gavage once/d for 2 weeks, while mice in the flunarizine group were given 6 mg/mL flunarizine+50% polyethylene glycol 400+50% saline by gavage at a daily dose of 30 mg/kg for 2 weeks. Body mass was recorded 1, 3, 5, 7, 10 and 14 d after drug administration, and motor function was assessed by rotarod test 14 d after drug administration; 16s RNA sequencing was performed in the feces to observe the intestinal flora; intestinal transit function was detected by Evans blue by gavage; and then, the mice were sacrificed and homogenate or frozen sections (brain and intestinal tissues) were prepared; dopamine-ergic neuron expression was detected by Western blotting; RT-qPCR was applied to detect the expressions of inflammatory factors in the substantia nigra, and immunofluorescent staining was used to detect the expressions of ZO-1 and Claudin-5 in the intestinal epithelial tissues. Results:Compared with the control group, the flunarizine group had lower body mass ratio 1, 3, 5, 7, 10 and 14 d after drug administration (ratio to body mass before drug administration). Compared with the control group, the flunarizine group had significantly shortened residence time in rod rotating and lower rotational speed when falling ( P<0.05). Compared with the control group, the flunarizine group had decreased tyrosine hydroxylase protein in the substantia nigra without significant difference ( P>0.05). Compared with the control group, the flunarizine group had significantly increased interleukin-6 and tumor necrosis factor-α in the substantia nigra (1.00±0.00 vs. 2.79±0.83; 1.00±0.00 vs. 3.39±1.37), significantly lower intestinal Evans blue propulsion rate (80.67%±4.51% vs. 50.67%±6.03%), and statistically decreased ZO-1 and Claudin-5 expressions in the colonic epithelial tissues (27.01±1.41 vs. 16.32±2.83; 37.00±2.80 vs. 24.52±2.12, P<0.05). Totally, 576 microorganisms were noted in both control group and flunarizine group, 744 in the control group alone, and 634 in the flunarizine group alone. The intestinal flora β diversity indices in the 2 groups were significantly different based on weighted Unifrac-principle coordinates analysis (PCoA, PCoA1: 39.88%; PCoA2: 30.69%). Compared with the control group, the microbial colony structure of mice in flunarizine group was dominated by phylum thick-walled bacteria and phylum warty microbacteria, and by families Muribaculaceae, Lachnospiraceae and Akkermansiaceae. Compared with the control group, the flunarizine group had significantly decreased relative abundance of Ackermannia spp. and Lactobacillus spp. in the intestinal flora ( P<0.05). Conclusion:Flunarizine may contribute to the pathogenesis of DIP by causing structural disturbances in the intestinal flora and inducing neuroinflammation based on the gut-brain axis.