Naoxintiong dose effects on inflammatory factor expression in the rat brain following focal cerebral ischemia

BACKGROUND: Certain components of tetramethylpyrazine, a traditional Chinese medicine, exhibit protective effects against brain injury. OBJECTIVE: To investigate the effects of different Naoxintong doses on expression of nuclear factor-kappa B (kappa B), interleukin-6, tumor necrosis factor-alpha, and complement 3 in rats following focal cerebral ischemia. DESIGN, TIME AND SETTING: The randomized experiment was performed at the Laboratory of Neurology, Second Hospital of Hebei Medical University from June 2004 to June 2006. MATERIALS: A total of 150 adult, healthy, male, Sprague Dawley rats, weighing 280-320 g, were selected. Naoxintong powder (mainly comprising szechwan lovage rhizome, milkvetch root, danshen root, and radix angelicae sinensis) was obtained from Buchang Pharmacy Co., Ltd. in Xianyang City of Shanxi Province of China. lot number 040608. METHODS: The rats were randomly assigned into sham operation, saline, high-close Naoxintong, moderate-dose Naoxintong, and low-dose Naoxintong groups, with 30 rats in each group. Rat models of middle cerebral artery occlusion were established using the suture method, with the exception of the sham operation group. Rats in the high-close, moderate-dose and low-dose Naoxintong groups received 4, 2, and 1 g/kg Naoxintong respectively, by gavage. Rats in the saline group were treated with 1 mL saline by gavage. All rats were administered by gavage at 5 and 23 hours following surgery, and subsequently, once per day. MAIN OUTCOME MEASURES: At 6, 24, 48, 72 hours, and 7 days following model establishment, brain water content was measured. Histopathological changes in brain tissues were detected using hematoxylin-eosin staining. Expression of nuclear factor- kappa B, interleukin-6, tumor necrosis factor-alpha, and complement 3 was examined by immunohistochemistry. RESULTS: A total of 150 rats were included in the final analysis with no loss. Brain water content was significantly increased in the ischemic hemisphere of rats from the saline, as well as the high-dose, moderate-dose, and low-dose Naoxintong groups at 24 hours, which reached it peak at 48 hours. At 6, 24, 48, 72 hours, and 7 days, brain water content was greater in the ischemic hemisphere of rats from the saline, as well as the high-dose, moderate-dose, and low-dose Naoxintong groups, compared with the sham operation group (P < 0.05). At 24 and 48 hours, brain water content was reduced in the high-dose and moderate-close Naoxintong groups, compared to the saline and low-dose Naoxintong groups (P < 0.05). In the saline, as well as high-dose, moderate-dose, and low-dose Naoxintong groups, neuronal edema was observed at 6 hours Surrounding the ischemic sites. Inflammatory cells appeared at 24 hours, reached a peak at 48 hours, and gradually diminished. A small amount of glial cell proliferation and neuronal degeneration were observed in the hippocampus at 72 hours following infarction. Microglial proliferation and aggregation were detected at 7 days after infarction. Expression of nuclear factor- kappa B, interleukin-6, tumor necrosis factor-alpha, and complement 3 was significantly less in the high-dose, moderate-dose, and low-close Naoxintong groups, compared to the sham operation group (P < 0.05). Expression of the above-mentioned inflammatory cytokines was lower in rat brain tissues of the high-dose Naoxintong group, compared to the low-dose Naoxintong group (P < 0.05). CONCLUSION: High-dose Naoxintong and moderate-dose Naoxintong significantly alleviated rat brain edema and decreased expression of nuclear factor- kappa B, interleukin-6, tumor necrosis factor-alpha, and complement 3 in brain tissues. The protective effect of high-dose Naoxintong was most significant.