Objective: To explore the effect of Suanzaoren decoction (SZRD) on the expression of astrocytes and microglia cells in the dorsal raphe nuclei (DRN) insomnia rats. Method: The insomnia rat model was established by intraperitoneal injection of DL-4-Chlorophenylalanine (PCPA)at the dose of 350 mg·kg-1 for two days. Rats were divided into control group

model group

SZRD groups

and estazolam group. The SZRD groups were treated by intragastric administration of SZRD at 15

7.5

3.75 g·kg-1 each day for seven days. The estazolam group was treated the same way using estazolam at 2 mg·kg-1 for 7 days. HE staining was use to check the neural damage in the DRN and test animal’s midbrain glial fibrillary acidic protein (GFAP); and OX42 expression was examined using immunohistochemical staining. Result: The level of neural damage in the DRN was significantly higher in the insomnia model group than in the control group(P<0.01). Insomnia model group rats showed significantly higher levels (P<0.01) of GFAP and OX42 positive cells in the DRN than control animals. Treatment animals receiving a high dose of SZRD (15 g·kg-1) showed significantly lower levels (P<0.01) of GFAP and OX42 positive cells in the DRN than insomnia model group animals. This treatment group showed no significant difference when compared to animals treated using estazolam. Conclusion: PCPA can damage the DRN neurons. Insomnia induced by PCPA can activate midbrain astrocytes and microglia. SZRD reduces midbrain GFAP and OX42 expression

and reduces the damage from PCPA. This may be one of the mechanisms for SZRD in treatment of insomnia.