Regulatory Effect of Modified Banxia Shumi Decoction on Orexin and Its Receptor in Hypothalamus of Insomnia Model Rats / 广州中医药大学学报

ABSTRACT

Objective To observe the therapeutic effect and mechanism of Modified Banxia Shumi Decoction on p-chlorophenylalanine(PCPA)-induced insomnia model rats.Methods Forty-eight male SD rats were randomly divided into six groups,i.e.,the normal group,the model group,the low-,medium-and high-dose groups of Chinese medicine and the Diazepam group,with 8 rats in each group.For 7 consecutive days before modeling,rats in the Chinese medicine low-,medium-and high-dose groups were treated with Modified Banxia Shumi Decoction for prophylactic treatment.Except for the normal group,PCPA-induced insomnia rat model was established in all groups.After modeling on day 1,each group continued to be administered the corresponding drug for 7 days.Body mass was monitored,open-field behavioral tests were performed,serum levels of orexin A(OXA)and orexin B(OXB)were detected by enzyme-linked immunosorbent assay(ELISA),the expression of hypothalamic orexin receptor 1(OX1R)was determined by immunohistochemistry,and hematoxylin-eosin(HE)staining was used to observe the pathologic changes in the hypothalamus of rats.Results(1)Before modeling,the growth trend of body mass of rats in each group was smooth,with no significant difference between groups;after modeling,except for the normal group,the growth rate of body mass of rats in each group slowed down or even declined;after 14 days of administration of Modified Banxia Shumi Decoction,the body mass of the Chinese medicine medium-dose group was significantly increased compared with that of the model group(P＜0.01).(2)Compared with the normal group,the model group showed an increase in the total distance of activity in the open field,the distance of activity in the central region and the number of times of entering the central region(P＜0.01),a significant increase in serum OXA and OXB contents(P＜0.01),a significant increase in the expression of hypothalamic OX1R(P＜0.01),and HE staining showed mild hyperplasia of the hypothalamic glial cells;compared with the model group,the total distance of activity in the open field,the distance of activity in the central region and the number of times entering the central region were reduced in the rats in the Chinese medicine medium-dose group and the Diazepam group(P＜0.01),the levels of serum OXA and OXB were significantly reduced(P＜0.01),the expression of hypothalamic OX1R was significantly reduced(P＜0.01),and the HE staining showed that a large number of neurons with perineurial interspace enlarged and the local glial cell hyperplasia.Conclusion Modified Banxia Shumi Decoction can improve insomnia and reduce anxiety in rats by down-regulating the levels of OXA and OXB in serum and the expression of OX1R in the hypothalamus.