Study On The Function And Mechanism Of Aquaporin 4 In Hypoglycemic Edema Of Astrocytes

Objective To investigate the role of AQP4 in hypoglycemia induced cell edema in astrocytes and its mechanism.Methods We first compared the cell volume between primary astrocytes and astrocyte cell line CTX TNA2, treated with hypoglycemia(0.2m M glucose). Then the expression of AQP4 in primary astrocytes and CTX TNA2 was detected. To invest the role of AQP4 in hypoglycemia induced cell edema, the recombinant plasmid p EGFP-C2-AQP4-M23 was constructed, and we got the plasmid transfected into CTX TNA2 cells. The cells were treated with hypoglycemia, and the changes of cell volume were observed. The primary astrocytes were treated with AQP4 Si RNA to inhibite the expression of AQP4, and we detected the changes of cell volume in low glucose. To better understand the mechanism, mutated p EGFP-C2-AQP4-M23 plasmids, S111 A and S180 A, were constructed. All the datas were analysed by SPSS 16.0 software.Results The primary astrocyte cell volume increased in hypoglycemia, while CTX TNA2 cell volume did not change. The primary astrocytes expressed AQP4, but CTX TNA2 did not. The CTX TNA2 cells expressed AQP4 when transfected with p EGFP-C2-AQP4-M23 plasmid, which was identified by AQP4 antibody. The cells expressing AQP4 were larger than those without AQP4 in hypoglycemia. Cell edema of primary astrocytes in hypoglycemia was inhibited by AQP4 Si RNA. After 24 h hypoglycemia, CTX TNA cells expressing AQP4,wild type and S180 A, were larger than cells in control group. But CTX TNA cells expressing S111 A mutated AQP4 had no difference from control group.Conclusion AQP4 is necessary for hypoglycemia induced cell swelling, And phosphorylation of AQP4 Ser111 site is the core key for this progress.