ABSTRACT
Objective To explore the possible mechanism by which thioredoxin-interacting protein (TXNIP) par?ticipated in early brain injury (EBI) of subarachnoid hemorrhage (SAH) via examination of the expression of TXNIP and its downstream apoptotic factors before and after intervention. Methods Subarachnoid Hemorrhage (SAH) was performed by endovascular perforation. Total 97 adult male SD rats were randomly divided into 6 groups:sham-operation (17), SAH (32), control siRNA (12), TXNIP siRNA (12), resveratrol control (12) and resveratrol injection (12). Western blot was used to examine the expression of TXNIP, p-ASK-1, Caspase-3 before and after intervention. Laser scanning confocal microscopy (LSCM) was used to detect the expression of TXNIP in neurons. The co-localization of TXNIP with apoptotic cells was examined by using fluorescent TUNEL. Mortality, behavior score and cerebral edema were also evaluated. Re?sults Mortality, behavior scores and brain edema were improved after TXNIP siRNA and resveratrol injection(P<0.05). LSCM showed that TXNIP was widely expressed in brain and mainly located in cytoplasm of neurons in SAH rats. Fluo?rescent TUNEL revealed the co-localization of TXNIP with apoptotic cells. The expression level of TXNIP was signifi?cantly higher in SAH group than in sham operation (P<0.05, n=3). The expression level of TXNIP gradually increased at 12h and still remained at high level at 72h (P<0.05). This increase was simultaneously accompanied by the increase in downstream apoptosis factors, p-ASK-1 and Caspase-3. Inhibition of TXNIP by siRNA or resveratrol significantly re?duced the expression of TXNIP, p-ASK-1 and Caspase-3 (P<0.05, n=3). Conclusion TXNIP gradually increases in ear?ly period after SAH and aggravates brain damage through activation of ASK-1 apoptosis signaling pathway, whereas inhi?bition of TXNIP may attenuate EBI through reduction of p-ASK-1 and Caspase-3 after SAH.
ABSTRACT
Objective To examine the iron content and the expression of hepcidin in early period after subarach-noid hemorrhage (SAH) in rats, and to explore the role of hepcidin in dysregulation of brain iron metabolism after SAH. Methods Totally 90 adult male SD rats were randomly divided into two groups:the sham-operation group and SAH group. The SAH model was established by single blood injection to prechiasmatic cistern. Immunohistochemical and Western Blotting were used to examine the expression of hepcidin at 12, 24, 48 and 72h after SAH. Meanwhile, Atomic Absorption Spectrometer was used to detect the iron content. Results Immunochemistry showed that hepcidin expression in rats in SAH group began to rise at 12 h(0.30±0.06)and gradually increased over time until 72 h(0.56±0.07)compared with the sham group(0.19±0.05). The expression of hepcidin was significantly higher in SAH group than in the sham group(F=31.911, P<0.05). Western blot showed that hepcidin expression in rats in SAH group began to rise at 12h(0.481±0.065) and gradually increased over time until 72h(1.627±0.143)Compared with the sham group(0.238±0.047). The expression of hepcidin was significantly higher in SAH group than in the sham group after SAH(F=147.314,P<0.05). Iron content in SAH group began to rise at 12h after SAH(58.50±9.19)and gradually increased until 72 h(99.34±7.68). The iron con-tents in SAH group were higher at every time points than those in sham group(43.51±4.59)(F=28.799,P﹤0.05). The ex-pression of hepcidin was correlated with the iron content in SAH group(r=0.914,P﹤0.01). Conclusion The increase in iron content following SAH is associated with the increased hepcidin expression.