Abstract: Objective To study the effect of age and gender on blood physiological and biochemical indicators of SPF SD rats，and establish the normal values background data of blood physiological and biochemical indicators of different ages and genders in SD rats. Methods 80 weaning 3 weeks old SPF SD rats were randomly divided into four experimental groups，4，12，24 and 48 weeks old. The blood physiological and biochemical indicators in rats were detected by fully automatic biochemical analyzer and blood cell analyzer，statistically analysed the indicators differences between the same gender but different age and the same age but different gender in rats. Results The values of the blood physiological and biochemical indicators of 4 weeks old rats，including WBC，RBC，HGB，HCT，MCV，MCH，MCHC，PLT，PCT，BA#，BA% and AST，CHOL，TP，GLU，CRE，ALT，ALP，BUN，TG，which were significantly different from those of the 12，24 and 48 weeks old rats（ P < 0.01 or P < 0.05）. BA% of 4 weeks old rats and BA# of 24 weeks old rats were both significantly different between the male and female（ P < 0.05），WBC and RBC were significantly different between the male and female of 12 and 24 weeks old rats（ P < 0.01 or P < 0.05），MCH and PCT were significantly different between the male and female of 48 weeks old rats（ P < 0.01）. CRE was significantly different between the male and female of 4 weeks old rats（ P < 0.01），AST，CHOL and BUN of 12 weeks old rats and GLU of 48 weeks old rats were both significantly different between the male and female（ P < 0.05），ALP was significantly different between the male and female of 4，12 and 24 weeks old rats（ P < 0.01 or P < 0.05）. Conclusion The blood physiological and biochemical indicators differences were statistically significant among SPF SD rats of same gender but different age，which also have some differences among SPF SD rats of same age but different gender.

Key words: SPF SD ratage, gender, blood, physiological indicator, biochemical indicator