Effects of basic fibroblast growth factor on mRNA expression of transforming growth factor-β1 and its receptor in neonatal rats after brain ischemia

Objective To address the neuroprotective mechanism of basic fibroblast growth factor(bFGF)on ischemic brain injury in neonatal rats.Methods Sixty-six brain ischemia models of 3-day-old Sprague-Dawley rats were made by occluding bilateral common carotid artery.The models were randomly divided into two groups:trial group and control group with 33 rats in each group.The rats of trial group were administrated bFGF 5μg/d through intraperitoneal injection,3 days consecutively.The other thirty-three rats were taken into the sham operation group.The number of gtial fibrillary acidic protein(GFAP)positive cells in the subventricular zone of rata'brain was observed with immunofluorescence assays at the 4th,7th and 14th days after the operation.The mRNA expression of transforming growth factor-β1(TGF-β1)and its receptor Smad2 in the subventricular zone were examined by real-time PCR assays at the above mentioned time points respectively.Results (1)The number of GFAP positive cells in the subventricular zone of the sham operation group was highest at the 7th day(325.4±52.5),and it reached peak at the 14th day in the control group(533.5±75.7)and the trial group(727.2±104.5),there was a significant difference in three groups at each time point(P＜0.01).(2)TGF-β1 and Smad2 mRNA expression peaked at the 7th dayin control group(7.67±1.22,6.22±1.92,respectively),and it reached peak at the 14th day in the trial group(8.65±1.02,7.67±1.41,respectively),there was a significant difference in three groups at each time point(P＜0.01).Conchtsions Exogenous bFlGF could increase the number of astrocytes by inducing the expression of TGF-81 in the subventricular zone of neonatal rats after brain ischemia. Key words: Fibroblast growth factor 2; Brain ischemia; Transforming growth factor beta; As-trocytes; Rats