Effects of CX43 hemichannel on neuronal damage after ischemia-reperfusion injury

Abstract

To explore the CX43-hemichannels effects on rat hippocampus neuron damage after ischemia-reperfusion. A total of 128 Sprague-Dawley male rats were randomly divided into 4 groups of sham-operated group (sham), no treatment (I/R), connexin 43 mimetic peptide (I/R+Gap26) and normal saline (I/R+NS) (n = 32 each). TTC staining was used to examine each brain infarct volume after 24 h reperfusion. The levels of connexin 43 and astrocyte activation (glial fibrillary acidic protein) were assessed with Western blot and immunohistochemistry. And neuronal morphology of hippocampus was examined by Nissl stain and immunohistochemistry. As compared with sham group, brain infarction volume [(132 ± 7) mm(3) vs 0] and the expressions of astrocytic CX43 and GFAP protein in I/R group increased [CX43: (2.45 ± 0.56) vs (1.15 ± 0.43); GFAP: (146 ± 11) vs (76 ± 5), P < 0.05). And the damage of neuron increased versus I/R+NS group, brain infarction volume [(76 ± 6) vs (140 ± 10) mm(3)] and the expressions of astrocytic CX43 and GFAP were lower in I/R+Gap26 group [CX43: (0.43 ± 0.16) vs (2.15 ± 0.73); GFAP: (57 ± 6) vs (140 ± 9), P < 0.05] and neuronal damage lessened. Blocking CX43-hemichannel may reduce astrocytic activation and lessen the damage of hippocampus neurons after cerebral ischemia-reperfusion injury.