To explore the potential mechanism of acupuncture on oxidative stress level in the rostral ventrolateral medulla (RVLM) of spontaneously hypertensive rats (SHR) from the perspective of free radical source and elimination.Methods:A total of 15 Wistar (WKY) rats were in the normal group，and 45 SHR rats were randomly divided into a model group，an acupuncture group and a non-acupoint group.In the acupuncture group，“Taichong” acupoints were used for treatment once a day for 14 days.In the non-acupoint group received superficial needling was used.The effects of acupuncture on blood pressure were measured by telemetry; the effects of acupuncture on the changes of reactive oxygen species (ROS) in RVLM were detected by DHE staining; the effects of acupuncture on the activities of superoxide dismutase (SOD)，nitrogen synthase (NOS) and NADPH oxidase activity in RVLM were detected by chemiluminescence; and the effects of acupuncture on the subunits or subunits expression of NADPH oxidase，SOD and NOS in RVLM were detected by Western Blot.Results:Compared with the normal group，the systolic blood pressure of the model group was significantly increased (P<0.05)，ROS production in RVLM increased (P<0.05)，the NADPH oxidase activity increased (P<0.05)，and the protein expression levels of gp91phox，p22phox and nNOS were significantly increased (P<0.05).Compared with the model group and non-acupoint group，acupuncture intervention could significantly down-regulate the systolic blood pressure of SHR rats (P<0.05)，the level of ROS in RVLM (P<0.05)，and the activity of NADPH oxidase (P<0.05).There was no significant change in the SOD and NOS activities，the protein expression of SOD1，SOD2 and iNOS among each groups.Conclusion:Acupuncture could significantly reduce high blood pressure and ROS levels in the RVLM of SHR rats.The mechanism may be related to the down-regulation of the expression of NADPH oxidase subunits gp91phox，p22phox and NOS subtype nNOS.