Effects of Hydrogen Gas on Blood-brain Barrier Damage and Cognitive Dysfunction in Wild Type and Nrf2-knock out Mice with Sepsis
XU Ge,YU Yang,YANG Man
Department of Anesthesiology,Tianjin Medical University General Hospital, Tianjin Institute of Anesthesiology, Tianjin 300052, China
Abstract:
Objective To explore whether H2 can protect blood-brain barrier (BBB) and reduce sepsisassociated encephalopathy (SAE) through Nrf2 dependent pathway. Methods 152 female wild-type (WT) and 152 Nrf2 knockout (Nrf2-/-) C57BL/6J mice were randomly divided into Sham group, Sham+H2 group,CLP group and CLP+H2 group. In CLP and CLP+H2 groups, cecal ligation and puncture were performed to prepare sepsis model. Sham group and Sham+H2 group mice were only underwent open surgery. Sham group and CLP+H2 group mice began to inhale 2% H2 for 60 minutes at 1h and 6h after CLP or sham operation. 24 hours after sham operation or CLP, 20 mice in each group were randomly selected to observe and record the natural survival rate for 7days. 4 mice in each group were randomly selected to detect the blood-brain barrier injury by Evans blue extravasation method. 4 mice in each group were randomly selected to extract the cortex and the levels of VE-cadherin and ZO-1 were detected by Western blot. The rest 10 mice in each group were tested with Morris water maze for 7 days when 4days after sham operation or CLP operation to evaluate the cognitive function. Results In WT mice, the 7-day survival rate of CLP+H2 group (60%) was significantly higher than that of CLP group (35%) (P<0.01). The extravascular Evans blue extravasation in CLP+H2group [(3.68 ± 0.18) μg/g] was significantly lower than that in CLP group [(5.24 ± 0.06) μg/g] (P<0.05). The escape latency of CLP+H2 group[d6:(20.86±4.99)s;d7:(15.01±4.43)s;d8:(15.45±4.95)s;d9:(15.81±6.65) s;d 10 :( 12 . 37 ±4 . 15 )s] were significantly increased than those of CLP group [d 6 :( 41 . 62 ±12 . 94 )s; d7:(39.37±12.74)s; d8:(36.95±9.64)s; d9:(34.55±13.57)s; d10:(29.45 ±9.13)s] (all P<0.01).The time of crossing platform [(4.10 ± 0.99) times] in CLP+H2 group was significantly higher than that in CLP group [(1.20 ± 0.79) times] (P < 0.01);VE-cadherin/β-actin level (0.37 ± 0.02) was significantly higher than that in CLP group (0.18 ± 0.01) (P< 0.01), and ZO-1/β-actin level (0.46 ± 0.02) was significantly higher than that in CLP group (0.20 ± 0.01) (P < 0.01).There was no signi?cant difference in Nrf2 - / - mice (P> 0.05). Conclusion Inhalation of 2% H2 can protect BBB by reducing the permeability of BBB through Nrf2 dependent pathway, thus reducing SAE and improving cognitive function.
