Abstract: Objective To select refined methods from the three methods of amputation of the tail tip, lateral tail incision and periorbital puncture, for multiple blood sampling in rats. Methods Three methods of amputation of the tail tip, lateral tail incision and periorbital puncture, were selected for blood sampling on Wistar rats. For each methods, four samples were drawn at 0min, 20min, 60min and 120min. Indexes of CORT, blood glucose and haematological parameters were measured to study the effects on rats. Results Compared with control group, CORT significant increased in the three blood sampling groups. CORT in the group of periorbital puncture was significant higher than in the other blood sampling groups. During the four samplings, amputation of the tail tip and lateral tail incision all influenced blood glucose,while periorbital puncture resulted in a dramatic increase in blood glucose of up to 3 mmol/L. Compared the three blood sampling groups, the initial blood glucose in the group of periorbital puncture was significant higher than the other two groups, while there were significant differences in the haematological parameters of WBC, RBC, HGB, HCT and PLT. Conclusion For the three methods, amputation of the tail tip and lateral tail incision caused smaller stress reaction than periorbital puncture, which relatively be refined methods for multiple blood sampling. Furthermore, periorbital puncture should not be applied for OGTT in rats.Blood samples drawn by different blood sampling methods may induce significant differences in the haematological parameters and blood glucose.

Key words: Rat, Multiple blood sampling, Endocrine parameters, Haematological parameters