BACKGROUND: Somatostatin is abundant in the hypothalamus,cerebral cortex,limbic system,and mesencephalon. Somatostatin mRNA expression in the brain of rats with spleen deficiency is noticeably reduced,as well as attenuation of cognitive function. OBJECTIVE: To observe the interventional effect of Guipi decoction on somatostatin level and somatostatin receptor 1 (SSTR1) mRNA expression in different encephalic regions of rats with spleen deficiency,and to compare the interventional effects of Guipi decoction,Chaihu Shugan powder,and Tianwang Buxin pellet. DESIGN: A randomized controlled observation. SETTING: Basic Medical College,Beijing University of Traditional Chinese Medicine. MATERIALS: Fifty adult Wistar male rats,of clean grade,weighing (160 ± 10) g,were provided by Beijing Weitong Lihua Laboratory Animal Technology Co.,Ltd. The protocol was performed in accordance with ethical guidelines for the use and care of animals. Somatostatin 1 polyclonal anti-rabbit antibody and SSTR1 in situ hybridization kit were provided by Department of Neuroanatomy,Shanghai Second Military Medical University of Chinese PLA. The drug for developing rat models of spleen deficiency was composed of Dahuang,Houpu and Zhishi,and prepared at 2:1:1. Guipi decoction,Chaihu Shugan powder,and Tianwang Buxin pellet recipes were made according to previous studies. METHODS: This study was performed at the Basic Medical College,Beijing University of Traditional Chinese Medicine from March 2002 to March 2005. The rats were randomly divided into 5 groups,with 10 rats in each group: normal,model,Guipi decoction,Chaihu Shugan powder,and Tianwang Buxin pellet groups. Rat models of the latter 4 groups were developed by methods of purgation with bitter and cold nature drugs,improper diet,and overstrain. The rats received 7.5 g/kg of the drugs each morning and were fasted every other day,but were allowed free access to water at all times. The rats were forced to swim in 25 ℃ water until fatigued. Rats in the normal group were intragastrically administered the same amount of normal saline. Rats in the Guipi decoction,Chaihu Shugan powder,and Tianwang Buxin pellet groups were intragastrically administered 7.5 g/kg Guipi decoction,Chaihu Shugan powder,and Tianwang Buxin pellet,respectively,every afternoon. All rats were treated for 6 weeks. MAIN OUTCOME MEASURES: Somatostatin protein and SSTR1 mRNA expression in the ventral nucleus of hypothalamus,hippocampal CA1 region,and cortex of prefrontal lobe were determined by immunohistochemistry and in situ hybridization,respectively. RESULTS: Fifty rats were included in the final analysis. In the model group,expression of somatostatin protein and SSTR1 mRNA in the ventral nucleus of hypothalamus,hippocampal CA1 region,and cortex of prefrontal lobe were significantly less than in the normal group (P < 0.01). Above-mentioned indices were identical in the Chaihu Shugan powder and model groups. However,expression of somatostatin protein and SSTR1 mRNA were significantly higher in the Guipi decoction group compared to model group (P < 0.01). In the Tianwang Buxin pellet group,SSTR1 mRNA expression in rat ventral nucleus of hypothalamus and somatostatin level in rat hippocampal CA1 region and cortex of prefrontal lobe,as well as ventral nucleus of hypothalamus,were significantly higher compared to model group (P < 0.01). CONCLUSION: Somatostatin level and SSTR1 mRNA expression in rats with spleen deficiency were lower than in normal rats. Guipi decoction and Tianwang Buxin pellet up-regulated somatostatin level and SSTR1 mRNA expression.
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