BACKGROUND: To date, many 6-hydroxydopamine (6-OHDA)-lesioned rat models have been established by injecting 6-OHDA into two or more sites in the substantia nigra pars compacta, striatum or median forebrain bundle. The success rate of models established by this method is satisfactory, but it can raise the death rate, and is elaborate and tedious to perform. OBJECTIVE: To observe the difference between injections of 6-OHDA into the striatum from one site and two sites, and to explore the feasibility of establishing Parkinson’s disease rat models via striatal one-site double injection. DESIGN, TIME AND SETTING: A randomized, controlled animal experiment based on a modeling comparison was performed at the Pharmacology Laboratory of Traditional Chinese Medicine, Academy of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine between August 2005 and April 2006. MATERIALS: A total of 46 male Wistar rats were purchased from Beijing Weitong Lihua Experimental Animal Technical Co., Ltd., China. 6-OHDA hydrogen bromide was sourced from Sigma Co., Ltd., USA. METHODS: All 46 rats were randomized to three groups: one-site injection (n = 18), two-site injection (n = 18), and control (n = 10). Lesions in rat brains were established by infusing 5 μg 6-OHDA into the striatum at the following coordinates: anteroposterior (AP) 1.0 mm, mediolateral (ML) 2.7 mm, dorsoventral (DV) -5.2 or -6.0 mm for the one-site injection group, and AP 1.0 mm, ML 2.5 mm, DV -4.5 mm/AP -0.4 mm, ML 3.5 mm, DV -4.5 mm for the two-site injection group, respectively. Rats in the control group were injected with the same volume of 0.01% ascorbic acid as above. MAIN OUTCOME MEASURES: Tyrosine hydroxylase-positive neurons were detected by immunohistochemistry. Success rates of PD models established by one-site and two-site injection techniques were examined. RESULTS: One rat died in the one-site injection group and four in the two-site injection group. Thus behavioral testing was performed on 31 rats. There was no significant difference in the success rate of PD model establishment between one-site injection and two-site injection groups [82% (14/17)vs. 86% (12/14), P > 0.05]. The numbers of tyrosine hydroxylase -positive neurons in one-site injection and two-site injection groups were not significantly different ( P > 0.05), but they were significantly lower than in the control group(P < 0.01). CONCLUSION: A Parkinson’s disease model can be established in rats via striatal one-site double injection. BACKGROUND: To date, many 6-hydroxydopamine (6-OHDA) -lesioned rat models have been established by injecting 6-OHDA into two or more sites in the substantia nigra pars compacta, striatum or median forebrain bundle. The success rate of models established by this method is satisfactory, but it can raise the death rate, and is elaborate and tedious to perform. OBJECTIVE: To observe the difference between injections of 6-OHDA into the striatum from one site and two sites, and to explore the feasibility of establishing Parkinson’s disease rat models via striatal one-site double injection. DESIGN, TIME AND SETTING: A randomized, controlled animal experiment based on a modeling comparison was performed at the Pharmacology Laboratory of Traditional Chinese Medicine, Academy of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine between August 2005 and April 2006. MATERIALS: A total of 46 male Wistar rats were purchased from Beijing Weitong Lihua Experimental Animal Technical Co., Ltd., China. 6-OHDA hydrogen bromide was sourced from Sigma Co., Ltd., USA. METHODS: All 46 rats were randomized to three groups: one- site injection (n = 18) Lesions in rat brains were established by infusing 5 μg 6-OHDA into the striatum at the following coordinates: anteroposterior (AP) 1.0 mm, mediolateral (ML) 2.7 mm, dorsoventral (DV) -5.2 or -6.0 mm for the one-site injection group, and AP 1.0 mm, ML 2.5 mm, DV -4.5 mm / AP -0.4 mm, ML 3.5 mm, DV -4.5 mm for the two-site injection group, respectively. Rats in the control group were injected with the same volume of 0.01% ascorbic acid as above. MAIN OUTCOME MEASURES: Tyrosine hydroxylase-positive neurons were detected by immunohistochemistry. Success rates of PD models established by one-site and two -site injection techniques were examined. RESULTS: One rat died in the one-site injection group and four in the two-site injection group. Thus behavioral testing was per fThere was no significant difference in the success rate of PD model establishment between one-site injection and two-site injection groups [82% (14/17) vs. 86% (12/14), P> 0.05 The numbers of tyrosine hydroxylase-positive neurons in one-site injection and two-site injection groups were not significantly different (P> 0.05) but they were significantly lower than in the control group (P <0.01). CONCLUSION: A Parkinson’s disease model can be established in rats via striatal one-site double injection.