OBJECTIVE: To explore the effect of parecoxib on cerebral infarction in rats and the regulatory mechanism on hypothalamus orexin neurons (orexin) and protein expression. MATERIALS AND METHODS: 60 SD male rats were randomly divided into sham operation group, model group and treatment group (20 rats in each group). Cerebral infarction model was established by modified Longa method. Rats in the treatment group were given pare-coxib (2.5 mg kg-1) in tail by intravenous injection , while both the

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... m operation group and the model group were given the equal volume of sterile PBS solution in the tail vein. Continuous intervention of 72h was carried out in the three groups. Immunofluorescence staining and Western blot were used to detect the expression of orexin neurons and orexin protein in the hy-pothalamus of rats, respectively. RESULTS: Immunofluorescence staining showed that the number of orexin positive cells in the model group was significantly less than that in the sham-operated group (p < 0.01). After treatment intervention, the number of orex-in positive cells in the hypothalamus was significantly increased compared to that in model group (p < 0.01). Western blot analysis showed that compared with sham operation group, the expression of orexin in the hypothalamus of model group was significantly decreased (p < 0.01), whereas the expression of orexin protein was significantly elevated after parecoxib intervention (p < 0.01). CONCLUSIONS: Parecoxib plays a therapeutic effect on cerebral infarction by up-regulating the orexin neuron.