Objective        To establish a model of chronic bacterial prostatitis (CBP) in rats by fine needle injection of E. coli under the guidance of ultrasound.       Methods        A total of 36 clean adult male rats weighing 280～300 g were randomly divided into 3 groups (n=12)

that is

normal control

conventional CBP model group and fine needle injection model group. In 4 weeks after model establishment

the rats were all sacrificed and their prostate was harvested for morphological observation. The inflammation score

rat mortality and operation time for making model were studied and compared.       Results        The inflammation scores in gland morphological change

inflammatory cells infiltration

and fibrous hyperplasia were 3.22±0.31

3.71±0.37 and 3.80±0.29 respectively in the conventional CBP model group

and 3.24±0.36

3.65±0.41 and 3.70±0.33 respectively in the fine needle injection model group. The scores of the both groups were significantly higher than those in the normal control group (0.20±0.07

0.23±0.04 and 0.28±0.06

P0.05). What’s more

the rat mortality was obviously lower

and  the operation time for making model was remarkably shorter in the fine needle injection model group than the conventional CBP model group (P0.05).       Conclusion        Ultrasound-guided fine needle injection of E. coli into the rat prostate is a good method to establish stable rat CBP model

and has the advantages of easiness

convenience and lower mortality when compared with the conventional model establishment.