[Effect of improper diets on blood viscosity in SD rats in high-salt and fat diet and alcohol abuse simulation model].

Objective: To observe the effect of composite factors, like long-term high-salt & fat diet and alcohol abuse on blood viscosity and blood pressure in rats, and compare with a model induced by high molecular dextran, in order to build a chronic hyperviscosity aminal model which is similar to human hyperviscosity in clinic and lay a foundation for efficacy evaluation on traditional Chinese medicines.

Method: Male SD rats were randomly divided into the normal group, the high molecular dextran (HMD) group and the high salt & fat and alcohol (HSFA) group. The HMD group was given normal diet and water for 23 day and then 10% HMD through tail vein for 5 days. The HSFA group was fed with high salt and high fat diets every day and alcohol for 20 h x d(-1) for 13 weeks. After the modeling, whole blood viscosity and plasma viscosity were measured in the 5th, 8th and 11th week. Blood pressure was measured in the 5d, 7h, and 10th week. Red cell count (RBC) and hematocrit (HCT) were measured in the 11th week. PAgT, Fb, ET-1, NO, PGI, TXA2 contents of the normal group and the HSFA group were measured in the 13th week, and IECa21 content was measured with flow cytometry. Result: After the modeling, the HMD group was in good conditions with glossy hairs and active behaviors. The HSFA group was depressed with withered hairs and less activities. During the 5th-11th weeks, the HMD group and the HSFA group showed higher values in high and low shear whole blood viscosity (WBV) than the normal control group. The plasma viscosity (PV) of HMD rats was significantly increased only in the 5th week, and that of HSFA rats significantly increased in the 8"' and 11th week, particularly in the 11'h week. In the 111h week, the HSFA group showed significant increases in RBC and HCT. After the modeling, the blood pressure of HMD rats showed no significant changes, but the blood pressure of HSFA rats significantly increased during 7' and 101h weeks, particularly in the 10"' week. In the 13th week, PAgT, IECa2+, Fb, ET-1 of HSFA rats significantly increased, but with decreases in NO and PGI2.

Conclusion: Long-term high salt & fat and alcohol diets can cause abnormal blood viscosity in rats. WBV significantly increased since the 5th week in rats, and PV increased since the 8th week. The mechanism for increasing BV may be: (1) increases in RBC, HCT, and IECa2+, (2) PAgT increase, (3) Fb content increase, or (4) TXA2/PGI2, ET-1/NO imbalance. Although the modeling time with the method is longer than that with the HMD method, the model is more stable and moderate, and could lead to abnormal increases in WBV and PV; Whereas the HMD method only induced transient increase in plasma viscosity and abnormal increase in SBP. The model is more similar to traditional Chinese medicine syndromes and pathogenesis, with higher value for studies on efficacy of traditional Chinese medicines.