Tongqiao Huoxue Decoction Affects Memory And Learning Capability In Vascular Dementia Rats Based On Ca²⁺-CaMKII-CREB Pathway

With the accelerating process of population aging, morbidity of VD is growing,VD has been a hot area of research in the field of medical today, and is regarded as the only kind of dementia which can be preventable and treatable. Currently, the researches of traditional Chinese medicine prevention and therapy has been increasing daily, however, the certain pathological and physiological mechanism of VD is not clear, therefore, using advanced research method and screening scientific indicator can provide theoretical and experimental bases for exploration of basic research of VD and application of related traditional Chinese medicine.Tongqiao Huoxue decoction was created by Wang Qing-ren of China’s Qing Dynasty, is composed primarily of musk, semen persicae and radix paeoniae rubra,rhizoma ligustici wallichii, safflower, etc. “Yi Lin Gai Cuo” interpreted that peach seed and safflower act to promote blood flow and dredge collateral, red peony root and rhizoma ligustici wallichii activate blood circulation, ginger and chives activate Yang,yellow rice wine dredges collaterals, along with jujube acting to alleviate complicated properties of different herbs. Among all herbs, musk as the main drug is warm in nature, and specialized for promoting blood circulation and detoxication.Compatibility of ginger, chives and yellow rice wine make the effect of invigorationblood and Qi circulationthe more effective, thus make the Radix paeoniae rubra,rhizoma ligustici wallichii, peach kernel, safflower play more active roles in promoting the circulation of blood and stretching the sinew and the nerve.Ca²⁺signaling pathway play an important role in learning and memory signal transduction pathways. After entering cells, Ca²⁺bind to the Ca M, and form complex Ca²⁺-Ca M which could activate Ca MKII. Phosphatized Ca MKII can activate CREB directly, thereby further regulates synthesis of cytoskeletal protein and synaptic protein, promotes organization of neuron, and partly relates to the formation of long-term memory. The process of learning and memory signals transmitting from upstream to downstream progressively is regulated by p Ca MKII、p PKA、p CREB. The project preliminary studies shows that Tongqiao Huoxue decoction can effectively improve the shape and antioxidant capacity of pyramidal cells of hippocampus CA1 area of VD, and thereby improve the ability of learning and memory of rats. The molecular mechanisms of the effect of this prescription on VD has not yet been reported at home and abroad. To provide theoretical and experimental basis for the treatment of VD, our research group has further studied the Ca²⁺concentration, the expression of p Ca MKII, p PKA, p CREB, NMDA receptors m RNA, and the activity of Ach E、Ch AT in hippocampal neurons of rats, and discussed the molecular mechanism of the effect of Tongqiao Huoxue decoction on improving learning and memory ability of VD rats.ObjectiveThis study explores the effect of Tongqiao Huoxue decoction on the regulation of learning and memory of VD rats, and its regulation effect of cholinergic system and calcium ion signaling pathways In the process of VD treatment.Methods1. The rats were divided into sham operation group, model group, high-does group,middle-does group, low-does group and positive control group. Oral administration of Tongqiao Huoxue decoction to rats for 30 days.2.Using Morris water maze task to test the learning and memory ability of rats respectively.3.Using blood rheometer to test whole blood low shear viscosity, whole blood middle shear viscosity and whole blood high shear viscosity, and blood analyser to test erythrocyte aggregation and the deformed Index of rats.4.Using ELISA method to test the content of Ach E and Ch AT in hippocampal tissue homogenate of rats.5.Using flow cytometer to test the fluorescence intensity of Ca²⁺ in rat ’ s hippocampus neuron of each group.6.Using Western blot method to test CaMKII,PKA,CREB of rats’ hippocampal tissue and RT-PCR method to test the expression of m RNA of NMDAR 1, NMDAR 2A,NMDAR2 B of rats after treatment.Results1. Compared with model group, administration of Tongqiao Huoxue decoction with middle does and low does, the escape latent period and the total distance spent in finding and climbing the platform were significantly reduced.2. Compared with sham operation group, the whole blood low shear viscosity and whole blood middle shear viscosity, plasma viscosity, erythrocyte aggregation and the deformed Index of model group were significantly increased; Compared with model group, the erythrocyte aggregation and the deformed Index, the whole blood low shear viscosity and whole blood middle shear viscosity, plasma viscosity were obviously decreased after administration of Tongqiao Huoxue decoction with high, middle does and low does.3. Compared with model group, the decreased content of Ach E and increased content of Ch AT of administered group with different levels may be a potential reason for restoring rats’ memory function.4. Compared with model group, the reduced fluorescence intensity of calcium ion of administered group may be a potential reason for restoring rats’ memory function.5. After administration, phosphorylation level of Ca MKII, PKA, CREB was increase with certain degree, the expression of m RNA of NMDA receptor was raised too.Conclusion1. TQHCD can improve the memory and learning ability of rats with VD significantly.2. Tongqiao Huoxue decoction could significantly improve abnormal hemorheological parameters and inhibit platelet aggregation of VD rats.3. Tongqiao Huoxue decoction could reduce the content of AchE and increase the content of Ch AT, the regulating effect of central cholinergic system may be a one of the potential reasons for restoring rats’ memory function.4. The therapeutical effect of Tongqiao Huoxue decoction on VD rats may be related to its effects of inhibition of excessive high calcium ion concentration in hippocampus neurons, alleviating injury action of abnormally increased intracellular calcium ions and upregulating Ca/Ca MKII/CREB pathways.