Effect of Taurine on the expression of glucose regulated protein 78 and growth arrest and DNA damage - in-ducible protein 34 in zebrafish larvae brain after hypoxia/reoxygenation brain injury / 中华实用儿科临床杂志

ABSTRACT

Objective To investigate the expression of endoplasmic reticulum stress - related factors, glucose - regulated protein 78(GRP78)and growth arrest and DNA damage - inducible protein 34( GADD34)and neuronal apoptosis in the brain of zebrafish larvae after hypoxia/ reoxygenation brain injury,and the neuroprotective role of Taurine. Methods The 5 day post - fertilization zebrafish larvae were randomly assigned to 3 groupscontrol group, hypoxia/ reoxygenation model group(model group)and Taurine treatment group(Taurine group). According to the dif-ferent time points for observation,each group was subdivided into 5 subgroups(1 h,3 h,6 h,24 h,48 h)with 100 ze-brafish larvae each. The pathological changes in the brain tissues and cell apoptosis were detected by fluorescence ter-minal deoxynucleotidyltransferase - mediated dUTP nick end - labeling( TUNEL). The expression of GRP78 and GADD34 mRNA in the brain of zebrafish larvae were detected by real - time quantitative reverse transcription PCR (qRT - PCR). The changes in GRP78 and GADD34 protein were detected by Western blot. Results (1)TUNELapoptosis index(AI)was increased after hypoxia/ reoxygenation,and reached the peak at 3 h in model group,the AI in Taurine group was decreased compared with that in the model group at the same time point(1 h22. 83 ± 1. 80 vs 30. 18 ± 1. 81,3 h23. 22 ± 2. 46 vs 42. 97 ± 4. 01,6 h16. 80 ± 1. 69 vs 22. 97 ± 1. 91,all P ﹤ 0. 05).(2)qRT -PCRthe expression of GRP78 and GADD34 mRNA was increased at 1 h after hypoxia/ reoxygenation,and reached the peak at 3 h in the model group,the expression in Taurine group was decreased compared with that in the model group at the same time point(GRP78 mRNA1 h2. 35 ± 0. 13 vs 5. 36 ± 0. 35,3 h3. 08 ± 0. 33 vs 4. 27 ± 0. 52,6 h1. 57 ± 0. 12 vs 3. 00 ± 0. 13,all P ﹤ 0. 05;GADD34 mRNA1 h5. 14 ± 0. 55 vs 7. 45 ± 0. 67,3 h2. 79 ± 0. 58 vs 5. 83 ± 0. 51,6 h1. 79 ± 0. 22 vs 3. 67 ± 0. 30,all P ﹤ 0. 05).(3)Western blotthe expression of GRP78 and GADD34 pro-tein was increased at 1 h,reached the peak at 6 h,but it was decreased in Taurine group(GRP78 protein1 h1. 12 ± 0. 11 vs 1. 37 ± 0. 13,3 h0. 79 ± 0. 11 vs 1. 25 ± 0. 10,6 h0. 55 ± 0. 10 vs 1. 52 ± 0. 14,all P ﹤ 0. 05;GADD34 pro-tein1 h0. 92 ± 0. 11 vs 1. 11 ± 0. 13,3 h0. 96 ± 0. 11 vs 1. 52 ± 0. 09,6 h0. 76 ± 0. 05 vs 1. 89 ± 0. 06,all P ﹤0. 05).(4)The expression of GRP78 and GADD34 protein was positively correlated with AI in the model group(r =0. 53,0. 56 respectively,all P ﹤ 0. 05). Conclusion One of neuroprotective mechanisms of Taurine against hypoxia/reoxygenation brain injury may down - regulate GRP78 and GADD34 expression.