Department of Pharmacology, School of Basic Medical Sciences, Anhui Medical University, NO.81 Meishan Road, Hefei 230032, China.
Department of Pharmacology, School of Basic Medical Sciences, Anhui Medical University, NO.81 Meishan Road, Hefei 230032, China.
Phytomedicine. 2023 Mar;111:154666. doi: 10.1016/j.phymed.2023.154666. Epub 2023 Jan 13.
We previously found that total flavones of Rhododendron (TFR) protected against the cerebral ischemia/reperfusion (I/R) injury. But the detailed mechanism is not clear. Recent research revealed that reactive astrocytes were divided into A1 and A2 phenotypes for their morphological and functional remodeling and neurotoxic- vs-neuroprotective effect on the injury of the central nervous system (CNS).
The present study was undertaken to explore the role and mechanism of TFR on the phenotypic change of astrocytes following cerebral I/R in vivo and oxygen glucose deprivation/re-oxygenation (OGD/R) in vitro.
We tested the expression of astrocytes marker glial fibrillary acidic protein (GFAP), A1 astrocytes marker C3 protein and A2 astrocytes marker S100a10, as well as the BrdU/GFAP-positive cells, GFAP/S100a10-positive cells and GFAP/C3-positive cells in mice hippocampal tissues to evaluate the phenotypic change of astrocytes. Besides, we assessed the change of astrocyte phenotypes following OGD/R in vitro.
We found that mice cerebral I/R promoted the astrocytes proliferation of both A1 and A2 phenotypes in hippocampal tissues. While treatment with TFR could promote the proliferation of A2 astrocytes but inhibit the A1 astrocytes proliferation in mice hippocampal tissues, suggesting that TFR could accelerate the astrocytes transformation into A2 subtype following cerebral I/R. Whereas, in OGD/R model of astrocytes, we found that TFR inhibited the proliferation of both A1 and A2 astrocytes. Besides, we found that TFR could up-regulate the release of cystathionine β-synthase (CBS)-produced hydrogen sulfide (HS) and inhibit RhoA/Rho kinase pathway, and revealed that the inhibitory effect of TFR on astrocytes proliferation could be blocked by aminooxyacetic acid (AOAA), an CBS inhibitor. Furthermore, TFR could ameliorate the mice cerebral I/R injury and the OGD/R-induced astrocytic damage.
These findings suggested that TFR could affect the transformation of astrocytes subtypes following cerebral I/R, which may be related to up-regulation of CBS-produced HS and subsequent inhibition of RhoA/ROCK pathway.
我们之前发现，金雀异黄素（TFR）可防止脑缺血再灌注（I/R）损伤。但是，其详细机制尚不清楚。最近的研究表明，反应性星形胶质细胞根据其形态和功能重塑以及对中枢神经系统（CNS）损伤的神经毒性和神经保护作用分为 A1 和 A2 表型。
本研究旨在探讨 TFR 在体内脑 I/R 及体外氧葡萄糖剥夺/再氧合（OGD/R）后对星形胶质细胞表型变化的作用及机制。
我们检测了星形胶质细胞标志物胶质纤维酸性蛋白（GFAP）、A1 星形胶质细胞标志物 C3 蛋白和 A2 星形胶质细胞标志物 S100a10 的表达，以及 BrdU/GFAP 阳性细胞、GFAP/S100a10 阳性细胞和 GFAP/C3 阳性细胞，以评估星形胶质细胞的表型变化。此外，我们评估了体外 OGD/R 后星形胶质细胞表型的变化。
我们发现，脑 I/R 促进了海马组织中 A1 和 A2 表型星形胶质细胞的增殖。而 TFR 处理可促进海马组织中 A2 星形胶质细胞的增殖，但抑制 A1 星形胶质细胞的增殖，提示 TFR 可加速脑 I/R 后星形胶质细胞向 A2 亚型转化。然而，在 OGD/R 模型中，我们发现 TFR 抑制了 A1 和 A2 星形胶质细胞的增殖。此外，我们发现 TFR 可上调半胱氨酸β-合成酶（CBS）产生的硫化氢（HS）的释放并抑制 RhoA/Rho 激酶通路，并且 TFR 对星形胶质细胞增殖的抑制作用可被 CBS 抑制剂氨基氧乙酸（AOAA）阻断。此外，TFR 可改善脑 I/R 损伤和 OGD/R 诱导的星形胶质细胞损伤。
这些发现表明，TFR 可影响脑 I/R 后星形胶质细胞亚型的转化，这可能与 CBS 产生的 HS 的上调及随后抑制 RhoA/ROCK 通路有关。
