神经影像学与苍艾挥发油在血管性认知障碍治疗中的作用机制

《Frontiers in Neuroscience》：Neuroimaging and molecular mechanism of action of Cang-ai volatile oil in the treatment of vascular cognitive impairment

血管认知障碍模型显示，Cangai挥发油（CAVO）通过调节内质网应激（ERS）通路，降低NLRP3炎症因子及BAX凋亡蛋白表达，增强前扣带回-梨状皮质等脑区功能连接，改善Morris水迷宫认知行为。

Cangai volatile oil (CAVO) is a traditional Chinese medicinal preparation known for its potential neuroprotective effects. This study explores the impact of CAVO on cognitive function in rats with vascular cognitive impairment (VCI), a condition resulting from cerebrovascular diseases and related risk factors. VCI is a growing concern globally, with increasing prevalence due to aging populations and associated risk factors like smoking, diabetes, and hypercholesterolemia. It is the second most common cause of dementia after Alzheimer’s disease, and its incidence is rising. Given the limitations of current treatments, such as cholinesterase inhibitors and NMDA receptor antagonists, which often come with adverse effects, there is a need for alternative therapeutic approaches.

CAVO is composed of multiple herbal ingredients, including Cangzhu, Ai Ye, Huo Xiang, Pei Lan, and Clove. Preliminary studies have highlighted its anti-inflammatory properties, which are critical in the context of VCI. Inflammation is known to play a significant role in the progression of various neurodegenerative diseases, including VCI. It can activate the endoplasmic reticulum stress (ERS) pathway, which is involved in cellular survival and apoptosis. Inhibiting ERS has been shown to enhance cognitive function in VCI models, suggesting that CAVO might act through this mechanism.

The study employs a combination of behavioral assessments and advanced neuroimaging techniques to evaluate the impact of CAVO. The Morris water maze test is a widely used method for assessing spatial learning and memory, and the results indicate that CAVO significantly improves these functions in VCI rats. Specifically, the escape latency, which measures the time taken to find the hidden platform, was notably reduced in the CAVO-treated group compared to the VCI group, suggesting improved cognitive performance. Additionally, the dwell time in the target quadrant was increased, indicating better memory retention.

Neuroimaging, particularly functional magnetic resonance imaging (fMRI), is used to examine changes in brain activity and connectivity. Resting-state fMRI (rs-fMRI) allows for the assessment of regional homogeneity (ReHo), a measure of local brain activity coherence, and functional connectivity (FC), which reflects the synchronization between different brain regions. The results from rs-fMRI show that CAVO treatment leads to enhanced FC in several brain regions, including the cingulate cortex-piriform cortex and the anterior cingulate cortex-hypothalamus. This improvement in functional connectivity suggests that CAVO may restore some of the disrupted neural communication patterns associated with VCI.

The study also incorporates molecular biology techniques to evaluate the expression of key proteins involved in inflammation, apoptosis, and ERS. Using Western blotting and polymerase chain reaction (PCR), the researchers found that CAVO significantly reduces the expression of inflammatory factors such as NLRP3, as well as apoptotic markers like BAX and Caspase3. At the same time, it increases the expression of Bcl-2, a protein that promotes cell survival. These findings support the hypothesis that CAVO may exert its cognitive-enhancing effects by modulating these pathways, thereby reducing inflammation and cellular damage in the brain.

The analysis of inflammatory markers through enzyme-linked immunosorbent assay (ELISA) further confirms that CAVO lowers the levels of cytokines such as IL-1β, IL-6, and TNF-α in the serum of VCI rats. These cytokines are known to contribute to neuroinflammation, which is a key factor in the development of VCI. By reducing their levels, CAVO may help to mitigate the inflammatory processes that lead to neuronal dysfunction and cognitive decline.

Histopathological assessments, including hematoxylin and eosin (HE) staining and Nissl staining, reveal structural changes in the hippocampus, a brain region crucial for memory formation. In VCI rats, the hippocampal cells in the CA1 area showed signs of damage, such as irregular shapes and reduced nucleoli. However, CAVO treatment appears to reverse these changes, promoting the recovery of cell morphology and reducing the number of damaged cells. This is further supported by immunofluorescence and transmission electron microscopy (TEM) results, which show that CAVO mitigates cellular damage and promotes healthier mitochondrial function.

Transmission electron microscopy provides a detailed view of the ultrastructural changes in the hippocampal region. In the VCI group, mitochondria were observed to be swollen and disorganized, indicating cellular stress and dysfunction. In contrast, CAVO treatment resulted in more normal mitochondrial structures, suggesting a protective effect against cellular damage. These findings are consistent with the molecular data showing that CAVO reduces markers of apoptosis and inflammation, which are known to contribute to mitochondrial dysfunction.

The study also highlights the potential role of the ERS pathway in VCI pathogenesis. ERS is a cellular response to stress, which can lead to the activation of inflammatory pathways and apoptosis. The results show that CAVO reduces the expression of ERS-related proteins such as CHOP, PERK, and GRP78 in the hippocampal tissues of VCI rats. This indicates that CAVO may help to restore normal ER function, thereby preventing the cascade of events that lead to cognitive impairment.

In addition to these findings, the study discusses the broader implications of these results. VCI is often associated with age-related changes and vascular risk factors, and early detection and intervention are crucial for managing the condition. The use of fMRI and other neuroimaging techniques allows for the non-invasive assessment of brain function and connectivity, which can be valuable in understanding the mechanisms underlying VCI and in developing targeted therapies.

The limitations of the study include the relatively small sample size, which may affect the statistical power of the results. Future research could explore the specific mechanisms of CAVO using pathway-related agonists and inhibitors, which might provide more detailed insights into its effects on the ERS and inflammatory pathways. Additionally, the study could be expanded to include a wider range of VCI models and more diverse populations to enhance the generalizability of the findings.

In conclusion, this study demonstrates that CAVO has a significant impact on cognitive function in VCI rats by modulating the ERS pathway and reducing inflammation and apoptosis. These findings provide a foundation for further research into the therapeutic potential of CAVO and its application in the treatment of VCI. The integration of neuroimaging and molecular biology techniques offers a comprehensive understanding of the effects of CAVO, highlighting its potential as a natural alternative to conventional treatments. The results suggest that CAVO may offer a promising approach for improving cognitive function in VCI, with implications for the development of new therapeutic strategies.