Objective

2

To observe the effect of

Huayu Tongluo

moxibustion on the NOD-like receptor protein 3 (NLRP3)/cysteine-aspartic acid protease-1 (Caspase-1)/gasdermin D (GSDMD) signaling pathway in rats with vascular dementia (VD)

and to explore its mechanism in improving learning and memory ability and alleviating neuronal injury in the hippocampal CA1 region.

Methods

2

A total of 80 SPF-grade male Wistar rats were included. Three rats were excluded based on the Morris water maze test. From the remaining rats

12 were randomly selected as the sham operation group. The rest were used to establish VD models via modified bilateral common carotid artery ligation. Thirty-six successfully modeled rats were randomly divided into a model group

a medication group

and a moxibustion group

with 12 rats in each group. The medication group was treated with nimodipine solution (12 mg/kg) via gavage. The moxibustion group was treated with

Huayu Tongluo

moxibustion. The suspended moxibustion was applied at Shenting (GV24) and Dazhui (GV14)

and aconite cake-separated moxibustion was applied at Baihui (GV20)

with each acupoint treated for 20 min. All treatments were administered once daily for 21 consecutive days. Before and after modeling

and after intervention

the Morris water maze test was used to assess cognitive function. After intervention

the activation and morphology of microglia in the hippocampal CA1 region were observed by immunofluorescence. Ultrastructure of hippocampal CA1 neurons was examined by transmission electron microscopy. Western blot was used to detect protein expression of NLRP3

apoptosis-associated speck-like protein (ASC)

Caspase-1

GSDMD

and interleukin-1β (IL-1β) in the hippocampal CA1 region. ELISA was used to detect the content of IL-6

IL-8

and tumor necrosis factor-α (TNF-α) in the hippocampal CA1 region.

Results

2

Compared with the sham ope

ration group

the model group showed longer mean escape latency (

P

<

0.01) and fewer platform crossings (

P

<

0.01); the microglial processes in the hippocampal CA1 region were thickened

cytoplasm was hypertrophic

and relative fluorescence intensity of ionized calcium-binding adapter molecule 1 (IBA-1) was increased (

P

<

0.05); the neuronal ultrastructure in the CA1 region was severely damaged

rough endoplasmic reticulum was swollen

mitochondria were deformed and swollen

some cristae were ruptured or dissolved

showing vacuolar changes; the protein expression of NLRP3

ASC

Caspase-1

GSDMD

and IL-1β

as well as levels of IL-6

IL-8

and TNF-α were significantly elevated (

P

<

0.001). Compared with the model group

both the medication group and the moxibustion group showed shortened mean escape latency (

P

<

0.01) and increased platform crossings (

P

<

0.01); the microglial processes were thinner

and IBA-1 fluorescence intensity was decreased (

P

<

0.05); the neuronal ultrastructure in the CA1 region was partially improved; the protein expression of NLRP3

ASC

Caspase-1

GSDMD

and IL-1β

and levels of IL-6

IL-8

and TNF-α were significantly reduced (

P

<

0.001). Compared with the medication group

the moxibustion group showed shortened mean escape latency (

P

<

0.05) and more platform crossings (

P

<

0.05); the IBA-1 fluorescence intensity was decreased (

P

<

0.05); the neuronal ultrastructure in the CA1 region was improved; the protein expression of NLRP3

ASC

Caspase-1

GSDMD

and IL-1β

as well as levels of IL-6

IL-8

and TNF-α

were significantly lower (

P

<

0.001).

Conclusion

2

The

Huayu Tongluo

moxibustion could enhance learning and memory abilities in VD rats

inhibit excessive activation of microglia

and alleviate neuronal injury in the hippocam

pal CA1 region. Its mechanism may involve modulation of the NLRP3/Caspase-1/GSDMD signaling pathway

reduction of inflammatory responses.