Abstract: OBJECTIVE: To explore the effect of Tongluojiunao injection(TLJN) prepared with Sanqi(Radix Notoginseng) and Zhizi(Fructus Gardeniae) on the interaction between brain microvascular endothelial cells(BMECs) and astrocytes in an in vitro ischemic model.METHODS: First, an in vitro model of cerebral ischemia in BMECs or astrocytes was established by oxygen-glucose deprivation(OGD). TLJN was used as a medicine of intervention. The OGD-injuredBMECs were cultured in various astrocyte-conditioned media. Cell activity, alkaline phosphatase(AKP) and γ-glutamyl transpeptidase(γ-GT) activity,interleukin-1 beta(IL-1β), and tumor necrosis factor alpha(TNF-α) content in BMECs were determined.Additionally, OGD-injured astrocytes were cultured in various BMEC-conditioned media. Cell activity, as well as expression of brain-derived neurotrophic factor(BDNF) and glial cell-derived neurotrophic factor(GDNF) in astrocytes, were detected.RESULTS: The results of paracrine signaling of normal BMECs or astrocytes showed a protective effect on each other: conditioned media from normal astrocytes improved cell viability, AKP, and γ-GT activity, and reduced IL-1β and TNF-α content of injured BMECs; conditioned media from normal BMECs improved cell viability and expression of BDNF and GDNF in injured astrocytes. However, once the BMECs or astrocytes were injured by OGD, the protective effect decreased or disappeared. The above-mentioned protective induction was effectively recovered by TLJN intervention.CONCLUSION: The therapeutic benefit of TLJN was achieved by recovering two-way induction between BMECs and astrocytes, enhancing activity of injured BMECs and astrocytes, stabilizing enzymatic barriers, promoting expression of neurotrophic factors, and inhibiting inflammatory cytokines.

Key words: Endothelial cells, Astrocytes, Paracrine communication, Oxygen-glucose-deprivation, Tongluojiunao injection