Catalpol improves impaired neurovascular unit in ischemic stroke rats via enhancing VEGF-PI3K/AKT and VEGF-MEK1/2/ERK1/2 signaling.

Neurovascular unit (NVU) is organized multi-cellular and multi-component networks that are essential for brain health and brain homeostasis maintaining. Neurovascular unit dysfunction is the central pathogenesis process of ischemic stroke. Thus integrated protection of NVU holds great therapeutic potential for ischemic stroke. Catalpol, classified into the iridoid monosaccharide glycoside, is the main active ingredient of the radix from traditional Chinese medicine, Rehmannia glutinosa Libosch, that exhibits protective effects in several brain-related diseases. In the present study, we investigated whether catalpol exerted protective effects for NVU in ischemic stroke and the underlying mechanisms. MCAO rats were administered catalpol (2.5, 5.0, 10.0 mg·kg-1·d-1, i.v.) for 14 days. We showed that catalpol treatment dose-dependently reduced the infarction volume and significantly attenuated neurological deficits score in MCAO rats. Furthermore, catalpol treatment significantly ameliorated impaired NVU in ischemic region by protecting vessel-neuron-astrocyte structures and morphology, and promoting angiogenesis and neurogenesis to replenish lost vessels and neurons. Moreover, catalpol treatment significantly increased the expression of vascular endothelial growth factor (VEGF) through up-regulating PI3K/AKT signaling, followed by increasing FAK and Paxillin and activating PI3K/AKT and MEK1/2/ERK1/2 pathways. The protective mechanisms of catalpol were confirmed in an in vitro three-dimensional NVU model subjected to oxygen-glucose deprivation. In conclusion, catalpol protects NVU in ischemic region via activation of PI3K/AKT signaling and increased VEGF production; VEGF further enhances PI3K/AKT and MEK1/2/ERK1/2 signaling, which may trigger a partly feed-forward loop to protect NVU from ischemic stroke.

[Changes of EPO in rats with chronic renal failure and low immunity and reversal effects of Yougui Yin and exogenous EPO].

The aim of this paper was to observe the changes of EPO in rats with chronic renal failure and low immunity induced by adenine and to investigate the reversal effect of Yougui Yin(YGY)and exogenous EPO.SD rats were randomly divided into normal control group(n=20)and adenine-model group(n=90).The adenine-model group rats were given with adenine 150 mg·kg~(-1)for 14days by gavage administration,and then randomly divided into 8 groups as follows:model group(n=20),YGY groups(10,20,40 g·kg~(-1),10 in each group),rh EPO group(500,1 000,1 500 IU·kg~(-1),10 in each group),and Guilu Erxian Gao 10 g·kg~(-1)group(positive control group,n=10).From the 15th day,every group except normal control group received 150 mg·kg~(-1)adenine by gavage administration once every two days to maintain the model.Meanwhile,the rats in each YGY group and Guilu Erxian Gao group received corresponding drugs by gavage administration once a day for 30 days.The rats in rh EPO groups were subcutaneously injected with rh E-PO once every 3 days for 30 days.On day 46,rats were anesthetized to take blood and then sacrificed.The serum levels of creatinine,urea,glandular hormone,immunoglobulin,complement and interleukin,the proportion of T cells in the spleen,the killing rate of NKcells and the proliferative capacity of spleen cells were measured.Western blot was used to detect the key proteins in JAK2-STAT5 and NF-κB pathways mediated by EPO in kidney and spleen.As compared with the normal control group,the serum levels of CREA and UREA were increased significantly and the serum levels of ACTH,T and T3 were decreased significantly in the model group rats,indicating that the functions of kidney,adrenal gland,gonad and thyroid in rats were decreased.At the same time,the serum levels of Ig A,Ig G,Ig M,C3,C4,IL-2 and IL-6 were significantly decreased,the proportion of CD4~+,CD4~+/CD8~+T cell subsets,the killing rate of NK cell and the proliferation ability of spleen lymphocyte in spleen of the model group rats were significantly declined,indicating that the immune function of model group rats was decreased,and the model of kidney deficiency immunodeficiency was successfully constructed.As compared with the model group,both YGY and rh EPO significantly reduced serum levels of CREA and UREA,significantly increased serum levels of ACTH,T,T3,T4,Ig A,Ig G,Ig M,C3,C4,IL-2,and IL-6,increased the proportion of CD4~+,CD4~+/CD8~+T cell subsets,the killing rate of NK cell and the proliferation ability of spleen lymphocyte in spleen.YGY could significantly increase the content of EPO in serum.Both YGY and rh EPO could regulate the expression of EPOR,p-JAK2/JAK2,STAT5,NF-κB p50,NF-κB p65 and NF-κB IκB of EPO-mediated JAK2-STAT5 and NF-κB pathways in kidney and spleen.EPO is an important factor in the chronic renal failure and low immunity induced by adenine in rats.Exogenous EPO and YGY have significant reversal effects for the model rats.The mechanism of YGY may be related to the up-regulation of EPO in serum and regulating the expression of key proteins in EPO-mediated JAK2-STAT5 and NF-κB pathways in kidney and spleen.The mechanism of exogenous EPO may be related to regulating the expression of the key proteins in EPO-mediated JAK2-STAT5 and NF-κB pathways in kidney and spleen.