Icariin Attenuates OGD/R-Induced Autophagy via Bcl-2-Dependent Cross Talk between Apoptosis and Autophagy in PC12 Cells.

Icariin (ICA), an active component of Epimedium brevicornum Maxim, exerts a variety of neuroprotective effects such as antiapoptosis. However, the mechanisms underlying antiapoptosis of ICA in neurons exposed to oxygen-glucose deprivation and reperfusion (OGD/R) are unclear. The B-cell lymphoma-2 (Bcl-2) protein family plays an important role in the regulation of apoptosis and autophagy through Bcl-2-dependent cross talk. Bcl-2 suppresses apoptosis by binding to Bax and inhibits autophagy by binding to Beclin-1 which is an autophagy related protein. In the present study, MTT result showed that ICA increased cell viability significantly in OGD/R treated PC12 cells (P < 0.01). Results of western blotting analysis showed that ICA increased Bcl-2 expression significantly and decreased expressions of Bax, cleaved Caspase-3, Beclin-1, and LC3-II significantly in OGD/R treated PC12 cells (P < 0.01). These results suggest that ICA protects PC12 cells from OGD/R induced autophagy via Bcl-2-dependent cross talk between apoptosis and autophagy.

Crocetin inhibits leukocyte adherence to vascular endothelial cells induced by AGEs.

Advance glycation end products (AGEs) have been postulated to play an important role in diabetic complications such as atherosclerosis disease. Adhesion and migration of leukocyte to endothelial cells (EC) is one of the early key steps in the pathogenesis. Crocetin is an important ingredient of diet in India and also used in various systems of indigenous medicine. In this study, we investigated effect of crocetin on leukocyte adherence to bovine endothelial cells (BEC) induced by AGEs in vitro and the possible mechanisms involved. BEC were pre-incubated with crocetin (0.01, 0.1, and 1 microM) for 12 h and exposed to AGEs (100 microg/ml). Cells proliferation was determined by MTT; leukocyte-endothelial cell adhesion was assayed by myeloperoxidase methods; intercellular adhesion molecular-1 (ICAM-1) protein expression was studied by immunocytochemistry and mitochondrial membrane potential (MMP) was analyzed by the retention of rhodamine 123 (RH123); furthermore, levels of anion (O(2)(-)), malonicdialdehyde (MDA) in super cells culture and superoxide dismutase (SOD) in cells were also detected, respectively. Results demonstrated that crocetin could inhibit AGE-induced BEC growth suppression and significantly reduce adhesion rate of leukocyte to BEC (P < 0.01 or P < 0.05); ICAM-1 protein was also suppressed (P < 0.05). Furthermore, crocetin could increase activity of SOD (P < 0.05), decrease levels of MDA and O(2)(-) (P < 0.01). In addition, down-regulated MMP was also increased by crocetin (P < 0.01 or P < 0.05). These data revealed crocetin could prevent the adhesion of leukocyte to BEC and down-regulation the expression of ICAM-1, and the possible mechanisms might be related to its antioxidant activity, which is through up-regulation of the activity of antioxidant enzymes and protection for mitochondrion.