Research on the mechanism of hippocampal CA3 synaptic plasticity in diabetes mellitus with depression based on P2X7/NLRP3 signaling in microglia of the DG region
WANG Ting-ting
ZOU Man-shu
GUO Hai-peng
YU Xiao-shi
ZHANG Yao
XIANG Zi-xuan
SU Hai-long
WANG Yu-hong
HAN Yuan-shan
Abstract：Objective:To investigate the mechanism of the P2X purinoceptor 7(P2X7)-NOD like receptor family pyrin domain containing 3(NLRP3)pathway in diabetes mellitus with depression(DD).Methods:Sixty Sprague Dawley(SD)rats were randomly divided into six groups(n=10 per group):control(Con),diabetes mellitus(DM),depression(Dep),diabetes mellitus with depression(DD),positive drug[metformin(0.18g·kg-1)+fluoxetine(1.8 mg·kg-1)](Y),and P2X7 inhibitor[Brilliant Blue G(BBG),30 mg·kg-1].DD rat models were established using 4 weeks of high-fat diet feeding combined with intraperitoneal streptozotocin(STZ)injection,followed by 4 weeks of chronic unpredictable mild stress(CUMS)combined with single caging.Rats in the inhibitor group received daily intraperitoneal injections starting from day 15 of modeling for 14 consecutive days.After modeling and drug intervention,behavioral tests(open field test,forced swim test,Morris water maze)were used to assess depression-like behaviors and cognitive function.Serum levels of norepinephrine(NE),5-hydroxytryptamine(5-HT),and dopamine(DA)were measured by enzyme-linked immunosorbent assay(ELISA).Immunofluorescence was performed to detect hippocampal P2X7/Iba-1,NLRP3/Iba-1,postsynaptic density protein-95(PSD95),and synapsin-1(SYN1).Hippocampal neuronal damage was assessed using hematoxylin-eosin(HE)and Nissl staining.Western blotting was used to measure the expression of P2X7-NLRP3 axis-related proteins(P2X7,NLRP3,apoptosis-associated speck-like protein containing a CARD(ASC),caspase-1,interleukin-1β(IL-1β)and brain-derived neurotrophic factor(BDNF).Results:Both BBG and the positive drug effectively attenuated the loss of body weight and elevated fasting blood glucose in DD rats.Behavioral results showed that BBG and the positive drug reduced immobility time in the forced swim test,increased total distance traveled and total activity in the open field test,shortened escape latency,and increased the time spent in the target quadrant in the Morris water maze.Pathological results demonstrated that BBG and the positive drug ameliorated neuronal damage in the hippocampal region of DD rats.Biochemical analysis results indicated that BBG and the positive drug upregulated serum levels of 5-HT,DA,and NE.Immunofluorescence and Western blot results showed that BBG could reduce the expression of P2X7 and NLRP3 in the hippocampus,while increasing the expression of PSD-95,SYN-1,and BDNF.Conclusion:BBG exerts neuroprotective effects by inhibiting the P2X7/NLRP3 axis and hippocampal microglial activation,thereby ameliorating neuroinflammation and abnormal NLRP3 inflammasome activation.This leads to increased expression of synaptic-related proteins(PSD95,SYN)and BDNF in the hippocampus.
Keywords：P2X purinoceptor 7/NOD like receptor family pyrin domain containing 3 pathwaydiabetes with depressionsynaptic plasticityadult hippocampal neurogenesis
Publication Date：2026-06-15
Online Publishing Date：2026-08-14(First online date of this platform, not the publication date of the document)
Pages：13( 1200-1212 )