Experimental Research Of Neurogenesis In Hippocampus And Cortex Following Guinea Pig SAH

Objective:To investigate the effect of unilateral subarachnoid hemorrhage (SAH) on guinea pig neurogenesis.Methods:The animal model of unilateral SAH was established by infusing autogenic femoral artery blood after drilling into subarachnoid cavity. Twenty eight guinea pigs were randomly divided into four groups and each group includes:2control animal,2sham operation animals and3SAH model animals. Four groups experimental animal survived7d,15d,30d,60d respectively. Nissl’s staining and immunohistochemistry were used to observe Nissl body and newly born neurons in cortex, dentate gyrus and cortical infarction area.Results:The cortex of control and sham operation animal was intact in each experimental group, but that of SAH model was incomplete in15d,30d,60d experimental time-point, the area of cortical defect became larger with time-point forward. Cortical Nissl body abnormally distributed in each group SAH model and peaked at15d and30d time-point in edge of cortical defect. NeuN positive cells distributed abnormally in part cortex, and was seldom in cortical infarction area. The expression of DCX was up-regulated in SAH model’s cortex and dentate gyrus, peaked in7d and15d time-point. DCX positive staining was observed in15d corpus callosum and substantial Alba and intensive DCX staining was also observed at the edge of cortical defect. GFAP positive staining intensively existed at edge of cortical defect and formed a band separating normal region and infarction area. In infarction area no co-expression of DCX and NeuN was found, only sporadic NeuN positive staining cells was observed. At edge of infarction area immunofluorescence within DCX, Ki67and GFAP indicate: Co-expression between DCX and GFAP was found at15d and30d; Co-expression between GFAP and Ki67was found only in15d, no co-expression between DCX and Ki67was found at15d and30d.Conclusion:Unilateral SAH can lead to severe damage to infusing-blood side of cortex; SAH can enhance function of central nervous system, neurogenesis zone can generate new neuron to replace the damaged neuron and its compensation function; Astrocytes may have same characteristic with Neural stem cells in pathological neurogenesis event. In ischemic CNS diseases, Astrocytes maybe participates in neurogenesis event by means of differentiating new neuron.