ABSTRACT
Objective:To investigate the protective effect of schisandrin B (SchB)on the cerebral ischemia reperfusion injury of the rats and the influence in HSPA12B/PI3K/Akt signaling pathway,and to explore the mechanisms.Methods:130 SD rats were divided into sham group,cerebral ischemia reperfusion injury model group (model group),low dose of SchB group (SchB 3 mg· kg-1 ,SchB1 group),middle dose of SchB group (SchB 10 mg·kg-1 ,SchB2 group)and high dose of SchB group (SchB 30 mg·kg-1 ,SchB3 group)(n=26).The rats in sham group didn’t plug lines;the rats in model were used to establish ischemia reperfusion models;the rats in SchB1 ,SchB2 and SchB3 groups were firstly pretreated with different doses of SchB for 7 d,and then they were used to build cerebral ischemia reperfusion injury models.The nerve dysfunction of rats was evaluated by neurologic deficit score.The cerebral edema was detected by measuring the content of water in brain tissue.The morphological changes of brain tissue were observed by toluidine blue staining.The levels of nuclear factor kappa B (NF-κB), tumor necrosis factor-α(TNF-α),interleukin-1 (IL-1)and interleukin-6 (IL-6)in the brain tissue were detected by ELISA.Western blotting method was used to detect the protein expression levels of heat shock protein A12B (HSPA12B ), serine-threonine kinase (Akt ) and phosphorylation serine-threonine kinase (p-AKT ). Results:Compared with sham group,the neurologic deficit score of rats in model group was significantly increased (P <0.01),and the content of water in brain tissue was increased (P < 0.01 );the brain tissue structure was loosened,and the mesenchyme appeared edema;the NF-κB,TNF-α,IL-1,and IL-6 levels were increased (P <0.01),and the expression levels of HSPA12B and p-Akt proteins were decreased (P <0.01).Compared with model group,the neurologic deficit scores of the rats in SchB1 ,SchB2 ,and SchB3 groups were decreased (P <0.01),and the contents of water in brain tissue of the rats in SchB2 and SchB3 groups were decreased (P <0.05);the edema of nerve cells was alleviated,and the cavities were reduced;the NF-κB,TNF-α,IL-1,and IL-6 levels were decreased (P <0.05 or P <0.01),the expression levels of the HSPA12B protein in SchB2 ,and SchB3 groups were increased (P <0.05),and the p-Akt protein expression levels of the rats in SchB1 ,SchB2 ,and SchB3 groups were increased (P <0.01).Conclusion:SchB could protect the cerebral ischemia reperfusion injury of rats,its mechanism may be related to regulating the HSPA12B/PI3K/Akt signaling pathway and inhibiting the inflammatory reaction damage to the nerve cells of reperfusion.
ABSTRACT
Objective To explore the lipopolysaccharide (LPS)-induced changes of heat shock protein A12B (HSPA12B) expression and its effect on the permeability of human umbilical vein endothelial cells (HUVECs). Methods The HUVECs cultured in vitro were divided into four groups; control group (without any treatment); LPS group (1 #g/mL LPS); LPS + pIRES2EGFPHSPA12B-3Flag group (The HSPA12B gene overexpression plasmid was transiently transfected into HUVECs and then LPS of 1 #g/mL was added); and LPS+ pIRES2EGFP-3Flag group (The negative control plasmid was transiently transfected into HUVECs and then LPS of 1 #g/mL was added). The transendothelial electrical resistance (TEER) of HUVECs was measured by MERSSTX01 Electrode. The expression of VE-cadherin was studied by flow cytometry. RT-PCR and Western blotting analysis were used to examine the expression changes of HSPA12B mRNA and protein in HUVECs stimulated with LPS at various time points. Results It was showed that after stimulated with LPS, HSPA12B mRNA and protein were gradually upregulated, and peaked at 12 h. HSPA12B significantly increased the TEER value of HUVECs (P< 0. 001), and it could completely offset the decline of TEER value induced by LPS(P<0. 001). Besides, HSPA12B could cause upregulation of VE-cadherin expression. Conclusion HSPA12B can reduce the permeability of vascular endothelial cells by up- regulating the expression of VE-cadherin, thus protecting the vascular endothelial barrier function of endothelial cells.