Effects Of NGF On The Neural Cells And Egr-1 Gene Expression In Patients With Epilepsy

【Objective】To study the level of nerve growth factor (NGF) in the cerebrospinal fluid (CSF)of human epileptics. To investigate the number of survivable neural cells, GFAP (+)astrocytes and MAP2(+)neurons were exposed to the different levels of NGF in the hippocampus CA1 region of human epileptics. And the expression of Egr-1mRNA was investigated in the neural cells affected by NGF to explore the effect and mechanism of NGF on the injured neural cells attcaked by epileptic discharge.【Methods】Enzyme-linked immunosorbent assay (ELISA) was used to investigate the concentration of NGF in the CSF of the epileptic group (n=28) and the non-epileptic group (n=21). Acutely dissociated cell suspensions of human hippocampus CA1 region with non specific pathological changes (n=16) were divided into NGF group and non-added NGF controlled group respectively. There were three subgroups exposed to NGF at the doses of 12.5, 50, 100 ng/ml respectively. After 4 hr culturing, the astrocytes and neurons were immunostained by Bb staining combined with the special maker GFAP, MAP2..And the numbers of the total neural cells, astrocytes and neurons were counted under inversion fluorescence microscope. At the same time, the expression of Egr-1 mRNA in the neural cells was detected by semiquantitative RT-PCR analysis.【Results】1. The concentrations of CSF NGF were (27.31±6.36)pg/ml in the epileptic group, and (24.09±4.96) pg/ml in the controlled group. There was no significant difference in the levels of NGF between them (P>0.05).2. Among the different levels of NGF 12.5, 50, 100ng/ml, the numbers of neural cells of hippocampus CA1 region were (82.02±11.08), (104.71±14.24), (127.11±14.35) cells/VF respectively. There were significant differences between the NGF group and the non-added NGF group (67.71±9.21) cells/VF (P<0.01). At the same time, there were significant differences between two groups among the three NGF groups (P<0.05).3. The numbers of GFAP(+) astrocytes affected by three different levels of NGF above were (30.73±5.16), (44.25±6.76), (59.57±6.23) cells/VF respectively. There were differences between the NGF group and the non-added NGF group (23.11±4.39) cells/VF (P<0.01). There were also significant differences between two groups among the three NGF groups (P<0.05). The numbers of MAP2(+) neurons in the non-added group and the three different levels of NGF and were (8.82±1.74), (14.81±2.87), (22.51±3.10), (32.17±2.52) cells/VF respectively . There were differences between two groups among them (P<0.05).4. The percentages (median: interguartile range) of GFAP(+) astrocytes in neural cells of the hippocampus CA1 region of human epileptics affected by three different concentration of NGF 12.5, 50, 100ng/ml were 34.94(31.16-36.91)%, 38.49(34.70-39.9 4)%, 42.36(40.22-45.13)%, 45.92(43.79-51.53)% respectively and in the non-added NGF group was 0.35(0.31-0.37). At the same time, the percentages of MAP2(+) neurons in neural cells in the non-added group and the NGF groups were 13.01(10.65-15.55)%, 18.35(16.37-19.92)%, 21.94(21.36-22.84)%, 25.33(23.98-26.84)%. It showed the same tendency of the percentage of MAP2(+) cells or GFAP(+) astrocytes in neural cells affercted by three different levels of NGF(P>0.05).5. To compare the three different doses of NGF group with the non-added controlled, the expressions of Egr-1mRNA (AEgr-1/Aβ-actin) in the controlled group and the three different levels of NGF group were (0.46±0.14), (0.63±0.14), (0.80±0.15), (1.12±0.12) respectively. There were differences among them (P<0.01).There was positive correlation between the number of the survivable neural cells and Egr-1mRNA quantity(r=0.780,P<0.01) among three NGF group.【Conclusions】There is no significant difference of the level of NGF in human CSF between the epileptics group and the non-epileptic controlled. In vitro, NGF can play a protective role in the survivable neural cells and GFAP(+)astrocytes, MAP2(+)neurons in hippocampus CA1 of human epileptics in the short time. Moreover there is a kind of dose-effect relation between NGF and the activity of neural cells. The total number of survivable cells is increasing with ascending levels of NGF. There is the same protective effect as well on the GFAP(+) astrocytes as on the MAP2(+) neurons. NGF can protect the neural cells attacked by epileptic discharge by promoting the expression of Egr-1 gene.