The expression of Akt1 in hippocampus of rat model of temporal lobe epilepsy at different time

Abstract

Objective To study the expression of Akt1 in hippocampal neurons in temporal lobe epilepsy, and explore its role in the development of epilepsy. Methods Two hundred and ten healthy adult male Sprague⁃Dawley (SD) rats were randomly divided into normal group (n = 10), lithium chloride (LiCl) group (n = 10) and epilepsy group (n = 190). LiCl⁃pilocarpine (PILO) was used for animal model of epilepsy. Total protein was extracted from hippocampus and rat brain slices were obtained at different time points (0 h, 1 h, 6 h, 12 h, 24 h, 48 h, 7 d, 10 d, 30 d, 50 d) after status epilepticus (SE) in normal group and LiCl group. Western blotting technique was used for detection of total protein in the hippocampus, and gray value was analyzed by Quantity one software. Immunohistochemical staining was used to detect the expression of Akt1 protein in the hippocampus and microscopic counting method (× 200) was used to quantify positive nerve cells in hippocampal region. Results Compared with the control group, the expression of Akt1 protein in the hippocampus in epilepsy group was significantly increased at the beginning of SE and achieved to the peak at 30 d after SE (0 h: 4.09±0.04, t = 2.445, P = 0.034; 30 d: 0.52± 0.03, t = 1.214, P = 0.002). The expression level was quickly reduced and was lower than normal value at 24 h after SE (0.27 ± 0.06, t = 4.294, P = 0.000), and no significant differences were seen at other time points. In comparison with LiCl group, the Akt1 protein expression in hippocampus in epilepsy group began to decrease at 1 h after SE, and reached to the lowest level at 24 h after SE (0.27 ± 0.06, t = 4.134, P = 0.000). At 48 h after SE the Akt1 expression began to increase and achieved to the level of LiCl group at 7 d after SE. In immunohistochemical staining: Akt1 protein positive cells in hippocampal CA3 area immediately increased after SE and achieved to the peak (46.70 ± 2.90) at 12 h after SE, but decreased to normal level (16.20 ± 2.50) at 48 h after SE. The positive neurons increased again (25.00 ± 2.30) at 10 d and reached to peak level (44.10 ± 1.80) again at 30 d after SE, but began to reduce to normal level (22.30 ± 2.60) at 50 d after SE. In LiCl group, Akt1 protein expression in CA3 area was higher than that in normal group at 0 h (P < 0.05). Akt1 protein positive cells in CA1 and CA2 areas showed no significant difference among different groups (P > 0.05, for all). Conclusion The dynamic process of Akt1 protein expression in hippocampus and the CA3 area of hippocampus after SE showed a higher, lower, and then higher presentation, suggests a possible cellular protective effect against apoptosis and promotion for cell survival.

DOI：10.3969/j.issn.1672⁃6731.2012.05.015