In Vivo Study Of Neural Stem Cells In Adult Rat Brain

Part One In vivo detection of neural stem cells in adult rat brain and the effect of epidermal growth factor(EGF) OBJECTIVE: To detect the location of neural stem cells in adult rat brain, and evaluate the effect of EGF on proliferation of neural stem cells. METHODS: 45 healthy adult male SD rats weight 270～320g were used in this experiment. Rat were randomly distributed into 3 groups which are normal group, EGF group and vehicle control group. Each group contains 15 rats. Animals in the normal group were not given any drugs, while animals in the EGF group received a unilateral ventricle infusion of EGF. The infusion lasts for 7 consecutive days using a microinjection pump at a flow rate of lpl/min, with a concentration of 0.1mg/nil. This correlates to an infusion rate of SOOng/d. Animals in the vehicle control group were infused with 0.9% saline, with the same method and the same dose as the EGF group. In each group, 5 rats were given Bromodeoxyuridine (BrdU) i.p., 100mg/Kg every 2 hours for 10 hours before been killed. 1 hour after the last BrdU injection, animals were killed by an anesthetic overdose and transcardially perfused with 4% para- formaldehyde. The brain were removed and the immunohistochemistry examines were performed. The location and the number of neural stem cells were revealed by the counting of nestin positive cells. The proliferation of neural stem cells were revealed by the counting of BrdU labeled cells. RESULTS: Nestin positive cells were found in the subependymal zone of the lateral ventricle and in the dentate gyrus of hippocampus. In the cortex and the subependymal zone of Ill, IV ventricle, no nestin positive cells were detected. Double-label ininiunohistochemistry for nestin and BrdUshowd that part of nestin positive cells were aIso BrdU positive, whilepart of nestin positive cells were BrdU negative. This twlies tha someneural stem cells are continuately proliferting, while som are relativelyqulescen. After the infusion of EGF, the numbe of nestin positive cellsand nestin+ BrdU+ double labeled cells wee both incrasedsipeanti.(P<0.m)CONCLUSON: There are neural stem cells in the subependymal zone ofthe lateral ventricle. These cells express nestin whih is a kind ofinfordiate filament belong to muItipotential neural stem cells. Some ofthese cells are selfrenewing continately. The infusion of EGF to theventricle can promote the proliferation of neural stem cells.Pot Two Reaedon of neural 8tem cell8 cher traUmatic brain injmp andthe effeCt of EGFOBWW: To decide Whther or not neural stem cells of adult rat canproliferat6 and fferentiat6 into neurons and astrOCyt6s ds tr8UInaticbrain inUry. W the regulator of proliferatiOn and diffrentiaon.WDS: 60 healthy adult rnale SD rats weigh 270~320g were used inthis experimen. Ra wer randondy dischted into 3 groups whih arenoM group, ThI group and ThI + EGF group. A fluld-percussion braininUry model were used in this study. AnjInals in group 2 and group 3received a mederate brain inUry rnade by fluld perCUSSon at 1.5aAnosphere pressure. EGF infusion wee given to the in group 3 withthe sam method and dose as part one. Anhals were peford with 4%parafMdehyde at 1 week and 8 weeks after inUry respectively. Eachtim N is 5 M in each group received BrdU inection beforeMe. The method of BrdU inection and parafrmaldehyde perfusionis the sam as pot one. IrnmunocheIItistw of nestin BrdU, NSE, GFAPwer pedermed to detect the prolifertion and differentiation of neUralstem celIs after traurnatic brain inury, and the efha of EGF onproliferation and dmerentiation. The beam walking test, beam balancingtest and angling test were pehad to evaluate the effed of EGF on ratS'neural funtion.