[Huanglian jiedu decoction active fraction protects ipsilateral thalamus injury in MCAO rats through regulating astrocytes].

OBJECTIVE: To observe the protective effects of the Huanglian Jiedu decoction aqueous extract and its active fraction, which consists of total alkaloids, total flavonoids and total iridoid, on the thalamus of cerebral ischemia in rats.

METHOD: The rat model of middle cerebral artery occlusion (MCAO) was chosen. Male SD rats were randomly divided into sham-operation group, model group, aqueous extract group (800 mg x kg(-1)), total alkaloids group(44 mg x kg(-1)), total flavonoids group (50 mg x kg(-1)) and the total iridoid group (80 mg x kg(-1)). The rats were administered the appropriate drugs intragastrically once a day, for 7 days after surgery. An equivalent volume of saline was given in the sham surgery and model groups. The HE staining was adopted to observe the pathological changes. Determination of Glu and gamma-GABA in thalamus were detected by HPLC with fluorescence detection. The expression of GAD65 was examined with immunohistochemistry and double staining with uorescent-conjugated antibodies against GFAP and Cx43 was chosen in this study.

RESULT: The neurons degenerated in MCAO rats after cerebral ischemia 7 d. The content of Glu, gamma-GABA decreased (P < 0.05), the expression of GAD65 reduced (P < 0.05) and the expression of GFAP and Cx43 increased (P < 0.01) in thalamus of rats compared with sham-operation group. Huanglian Jiedu decoction aqueous extract, total alkaloids, total flavonoids and total iridoid reduced the degeneration of neurons. Total flavonoids could promote the expression of GAD65 (P < 0.05) and decrease the expression of GFAP and Cx43 (P < 0.01) in thalamus compared with model group while it could also increased the content of Glu,gamma-GA BA to normal levels. Compared with model group, Huanglian Jiedu decoction aqueous extract, total alkaloids and total iridoid could raise the expression of Cx43, and Huanglian Jiedu decoction aqueous extract could also increase the expression of GAD65 (P < 0.05). The expression of GFAP in Huanglian Jiedu decoction aqueous extract group, total alkaloids group and total iridoid group were not different compared with model group while the content of gamma-GABA decreased (P < 0.05) compared with sham-operation group.

CONCLUSION: The degeneration of nerve cells, the reduction of neurotransmitter amino acids content, the aberrant activation of astrocytes and the abnormal expression of GFAP and Cx43 will appear in thalamus of MCAO rats after ischemia. Huanglian Jiedu decoction total flavonoids could relieve the injury of nerve cell through inhibiting the abnormal activation of astrocytes and regulating the expression of GFAP and GAD65.