| Objective To study the changes of Neurons Activity and NO(nitric oxide) output after anoxia in primary cultured fetal rat neurons and to observe the effect on Neurons Activity and NO output in anoxic fetal rat neurons by propofol preconditioning or postconditioning in vitro. The expression of Hsp70(Heat Shock Protein 70), Hsp70mRNA and Hsc70(Heat Shock cognate Protein 70) mRNA was also observed in fetal rat neurons incubated with different concentration of propofol for different time in non-anoxia conditions, in order to clarify the neuroprotective mechanism of propofol at the cellular level and provid useful information for proper administering time and concentration of propofol in clinic. Methods The neurons of 16?8 days fetal rat were primarily free-serum cultured in vitro. The morphology of neurons was observed by inverted phase contrast microscopes. Neurons Activity was detected by MTT analysis>NO output was assayed with nitrate reductase method. The expression of Hsp70 was measured by immunohistochemical technique and the expression of Hsp70mRNA and Hsc70 mRNA was measured by in situ hybridization technique. Five parts were included in this study: 1. To study the effect of different concentration of propofol on Neurons Activity in primary cultured fetal rat neurons. Neurons were administrated either fresh culture medium (control group, n=16)or 1.4, 5.6, 14, 56, 140 u M of propofol( propofol group, n=16), and 1 hour later, OD was detected. 2. To study the effect of propofol preconditioning or propofol postconditioning on Neurons Activity and NO output in anoxic neurons. Neurons were randomly divided into four groups: Group I (n=8): Non-anoxic damage, no propofol; Group II (n=8): Anoxic damage. 37癈, 95% N2 + 5% CO2, 30min; Group III (n=8): Propofol preconditioning. According to the above, effective concentration of neuroprotection of propofol was selected, administrating into cell culture medium 1 hour before anoxia; Group IV (n=8): Propofol postconditioning. The concentration of propofol was similar with group III, administrating into cell culture medium after anoxia instantly for 1 hour. Then, group IK III, IV were divided into 5 sub-groups : the t1, t2, t4, t6 and t24 represented 5 re-oxygen time respectively. 3. To study the expression of Hsp70 in primary cultured fetal rat neurons incubated with different concentration of propofol for different time in non-anoxia condition. Neurons having been cultured for 12 days were randomlydivided into three groups: (1) Control group; (2) 14 u M Propofol; (3) 56 u M Propofol. Then, the Group (2)and (3) were divided into 4 sub-group: the t3-, t8% t24and t48 represented 4 administration time respectively. 4. To study the expression of Hsp70mRNA in primary cultured fetal rat neurons incubated with different concentration of propofol for different time in non-anoxia condition. Neurons having been cultured for 12 days were randomly divided into three groups: (1)Control group; (2)14 u M Propofol; (3)56 u M Propofol. Then, the Group (2)and (3) were divided into 5 sub-group : the tK t3, t6, tSand t24 represented 5 administration time respectively. 5. To study the expression of Hsc70mRNA in primary cultured fetal rat neurons incubated with different concentration of propofol for different time in non-anoxia condition. Neurons having been cultured for 12 days were randomly divided into three groups: ?Control group; ?4 u M Propofol; (3)56 u M Propofol. Then, the Group ?and (3) were divided into 5 sub-group : the tK i3^ t6, t8 and t24 represented 5 administration time respectively.Result: Using of 14 u M and 56 u M propofol for Ih in fetal rat neurons was found as effective concentration of neuroprotection, which could increase Neurons Activity. Anoxia for 30 min could decrease Neurons Activity and increase the NO output of the neurons. In propofol preconditioning or postconditioning group , Neurons Activity of all groups increased at 5 re-oxygen time, compared with that in anoxic group, and there was no difference between the two concentrations of propofol (14...
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