Endoplasmic reticulum (ER) stress might play an important role in a range of neurological diseases; however, this phenomenon's role in
subarachnoid hemorrhage (SAH) remains unclear. In this study, we explored the potential role of endoplasmic reticulum stress in early
brain injury following SAH.84 rats were used for an endovascular perforation-induced
subarachnoid hemorrhage model. The rats were intraperitoneally pretreated with the ER stress inducer
tunicamycin (Tm) or with the inhibitor
tauroursodeoxycholic acid (
TUDCA) before SAH onset. An intracerebral ventricular infusion of autophagy inhibitor
3-methyladenine (3-MA) was also used to determine the relation between autophagy and ER stress in early
brain injury following SAH. At 24h, rats were neurologically evaluated, and their brains were extracted for molecular
biological and histological studies. ER stress was activated in rats after 24h of SAH. Enhanced ER stress via Tm pretreatment significantly improved neurological deficits, attenuated the expression of pro-apoptotic molecules of
caspase-3 and reduced the number of TUNEL-positive cells. In contrast, the ER stress inhibitor
TUDCA aggravated neurological deficits and apoptotic cell death. Western blot analysis revealed that levels of the autophagic
protein Beclin 1 and the ratio of LC3-II to LC3-I were both increased by Tm infusion and reduced by
TUDCA administration. The suppression of autophagic activity with 3-MA attenuated Tm-induced anti-apoptotic effects. Our study indicates that ER stress alleviates early
brain injury following SAH via inhibiting apoptosis. This
neuroprotective effect is most likely exerted by autophagy activation.