["Tiaoshen Tongluo" electroacupuncture improves learning-memory ability by regulating microglial polarization via the Nrf2/TREM2 signaling pathway in rats with cerebral ischemia-reperfusion injury].

MCAO/R model rats exhibited significant neurological deficits and downregulation of hippocampal Nrf2, TREM2, and DAP12 proteins compared to sham groups.

• Both 7 d and 14 d model groups showed significantly increased mNSS compared to respective sham groups (P<0.01).
• Expression levels of hippocampal Nrf2, TREM2, and DAP12 proteins were significantly downregulated in model groups (P<0.05, P<0.01).
• Histological examination revealed loose arrangement of neurons and reduction in the number of Nissl bodies in the hippocampal CA1 region of model rats.
• The 14 d model group showed increased escape latency, decreased number of original platform crossings, and decreased time spent in the target quadrant (P<0.01) compared to 14 d sham group.

MCAO/R injury promoted M1 microglial polarization and increased pro-inflammatory cytokine TNF-α in the hippocampus.

• The 14 d model group showed a notable increase in the number of CD68+/Iba1+ dual-labeled (M1 type) cells in hippocampal CA1 compared to 14 d sham group (P<0.05).
• TNF-α protein expression in the hippocampus was significantly elevated in the 14 d model group compared to the 14 d sham group (P<0.01).
• Immunofluorescence double staining was used to determine proportions of CD68+/Iba1+ (M1 type) and CD206+/Iba1+ (M2 type) positive cells.

Electroacupuncture (EA) treatment reduced neurological severity scores and decreased hippocampal TNF-α expression while upregulating Nrf2 and TREM2 proteins.

• Both 7 d and 14 d EA groups showed reduced mNSS compared to respective model groups (P<0.01).
• TNF-α protein expression was reduced in both 7 d and 14 d EA groups compared to respective model groups (P<0.05, P<0.01).
• Nrf2 and TREM2 protein expression levels were upregulated in both EA groups compared to respective model groups (P<0.05, P<0.01).
• EA treatment alleviated loose neuronal arrangement in the CA1 region and increased Nissl bodies in hippocampal tissue.

Fourteen-day EA treatment improved spatial learning and memory performance in Morris water maze tests.

• The 14 d EA group showed a significant decrease in escape latency compared to the 14 d model group (P<0.01).
• The 14 d EA group showed increased number of original platform crossings and increased time spent in the target quadrant compared to the 14 d model group (P<0.05, P<0.01).
• These spatial memory improvements were not statistically reported for the 7 d EA group, suggesting 14 days of treatment was needed to achieve measurable cognitive benefits.

Fourteen-day EA treatment shifted microglial polarization from M1 to M2 phenotype and upregulated DAP12 and TGF-β proteins.

• The 14 d EA group showed a decrease in the number of CD68+/Iba1+ dual-labeled (M1 type) cells compared to the 14 d model group (P<0.01).
• The 14 d EA group showed an increase in the number of CD206+/Iba1+ dual-labeled (M2 type) cells compared to the 14 d model group (P<0.01).
• DAP12 protein expression was upregulated in the 14 d EA group compared to the 14 d model group (P<0.05).
• TGF-β protein expression was increased in the 14 d EA group compared to the 14 d model group (P<0.05, P<0.01).

Fourteen-day EA treatment was superior to 7-day EA treatment in reducing neurological deficits and upregulating TREM2 expression.

• Compared to the 7 d EA group, the 14 d EA group showed a further reduction in mNSS score (P<0.05).
• TREM2 protein expression was further upregulated in the 14 d EA group compared to the 7 d EA group (P<0.05).
• The 14 d EA group showed more compact neuronal arrangement in the CA1 region with morphological structure being close to normal compared to 7 d EA.
• EA was administered at acupoints GV20 (Baihui), GV24+ (Yintang), and bilateral LR3 (Taichong) and LI4 (Hegu) for 10 min per session, once daily.

The study used a rat MCAO/R model with Morris water maze screening to confirm learning-memory impairment before group assignment.

• Male SD rats were divided into sham groups (7 d and 14 d, n=10 each) and pre-model groups; MCAO/R was induced using the Koizumi intraluminal filament method.
• Only rats confirmed to have learning-memory impairment by Morris water maze were assigned to experimental groups (n=10 per group): 7 d model, 7 d EA, 14 d model, and 14 d EA.
• Outcome measures included mNSS, Morris water maze, HE staining, Nissl staining, immunofluorescence double staining, and Western blot.
• Western blot measured relative protein expression of Nrf2, TREM2, DAP12, TNF-α, and TGF-β in hippocampal tissue.