Protective effects of Progranulin against focal cerebral ischemia-reperfusion injury in rats by suppressing endoplasmic reticulum stress and NF-κB activation in reactive astrocytes

Abstract

The aim of this study is to explore the effect progranulin (PGRN) has on endoplasmic reticulum (ER) stress and the NF-κB activation in reactive astrocytes found in rat models with focal cerebral ischemia-reperfusion (I/R) injury. Sprague-Dawley (SD) rats were grouped into the sham, I/R, PGRN-high dose, PGRN-low dose, and negative control (NC) groups. TTC staining was applied in order to detect the cerebral infarction volume, a TUNEL assay to detect the apoptosis rate of neurons, an ELISA to measure MDA, SOD, iNOS, LDH, TNF-α, IL-1β, IL-6, and IL-10 levels, and both RT-qPCR and western blotting methods in order to detect PGRN, GFAP, GRP78, CHOP, and NF-κB p65 expressions. The astrocytes (AST) cells were then assigned into the normal, I/R, negative control (NC), PGRN-high dose, and PGRN-low dose groups. After completing the transfection process, the proliferative capacity of AST cells was detected by use of the CCK-8 assay. Both the in vivo and in vitro results, in comparison with the I/R and the NC groups, the PGRN-high dose and PGRN-low dose groups both presented a decrease in cerebral infarction volume, apoptosis rate of neurons, MDA, LDH, iNOS, TNF-α, IL-1β, IL-6 levels, and GFAP, GRP78, CHOP, NF-κB p65 expressions, and an increase in SOD, IL-10, and PGRN levels as well as cell proliferation depending on dosage. Based on our results, we came to the confirmation that PGRN can reduce neuronal apoptosis by mitigating ER stress in the reactive astrocytes as well as downregulating the inflammatory levels by suppressing the NF-κB signaling pathway.

Keywords: Endoplasmic reticulum (ER) stress; astrocyte; focal cerebral ischemia-reperfusion; nuclear factor kappa B; progranulin (PGRN).