Effects Of Acidic Fibroblast Growth Factor On Hippocampal Astrocytes Injury Induced By Gentamicin:Role Of Mitogen-Activated Protein Kinase Signal Pathway

Objective:To establish the cellular model of hippocampal astrocytes and detect the expression of P38,extracellular signal-regulated kinase(ERK)l/2 and c-jun N-terminal kinase (JNK)1/2.The purpose of this study was that to explore the mechanism of the protection of acidic fibroblast growth factor (aFGF)for hippocampal astrocytes from injury induced by gentamicin.Methods:Hippocampal astrocytes were isolated from newborn (24hours)Sprague-Dawley rats,digested,centrifugated and purified.The third generations of hippocampal astrocytes were identified by glial fibrillary acidic protein (GFAP) immunofluorescence.The purity above 95% was considered to be used in the study.Hippocampal astrocytes were cultured for 3 days in a 96-well culture plate and divided into 3 groups for the experiment:a.control group:normal culture;b.injury group(GM group):2.0g/LGM was added for 24 hours;c.protection group (aFGF+GM group):after adding 4.25ug/LaFGF,24 hours,then adding 2.0g/LGM,24 hours.Western blotting was adopted to detect the expressions of P38,ERK1/2 and JNK1/2.Results:(1)Cellular morphological observation:Under light microsc -ope, the cell of control group were stretched out long branch protrusions from their somas,appears the vital interweaving of network structure with their somas showing spindle and polygonal, exhibited strong refraction, outline were clear.Cellular morphology have changed in the injury group: some cells exhibiting shrinkage, the branch connection interrupting and even, losing the integrity of the cell structure. There were many granules and vacuoles in the cytoplasm; in the protection group, few particles and vacuoles existed in cytoplasm,cellular shrinkage were reduced, the somas morphological structure,cells fusion and lose were relieved,outline clearer.(2)Western Blotting was adopted to detect the expressions of P38,ERK1/2 and JNK1/2.The ERK1 increased in the injury group compared with the control group(P<0.05).Compared with the injury group, the p38 increased (P<0.05) and the ERK1 decreased (P<0.05) in the protection group.There was no significant difference among others (P>0.05).Conclusion:(1)Gentamicin may damage the hippocampal astrocytes through the ERK1.(2)aFGF could protect the hippocampal astrocytes injury induced by gentamicin.(3)The mitogen-activated protein kinase signal pathway,especially P38 and ERKl,may associate with the protection of aFGF for hippocampal astrocytes from injury induced by gentamicin.But the protection of aFGF may not by ERK2,JNK1/2.