Expression of Toll-like receptor 4 in hippocampus of rat model with temporal lobe epilepsy

Objective To investigate the expression of Toll-like receptor 4 (TLR4) protein in hippocampus of rat model with temporal lobe epilepsy after status epilepticus (SE) and explore its function in the pathogenesis of temporal lobe epilepsy. Methods Rat model with temporal lobe epilepsy was induced by lithium chloride (LiCl)-pilocarpine. Total protein was extracted from hippocampus and rat brain slices were obtained at different time points (0, 1, 6, 12, 24, 48 h and 7, 10, 30, 50 d) after SE. Western blotting and immunohistochemical staining were used for detection of the expression of TLR4 in the hippocampus. Results The results of Western blotting showed the TLR4 protein expression at 0, 1, 6, 12, 24, 48 h and 7, 10, 30 d after SE was higher than that in the control group (P < 0.05, for all), and the TLR4 protein expression at 50 d after SE showed no significant difference compared with the control group (P = 0.714). There was no significant difference between LiCl group and control group (P = 0.590). The results of immunohistochemistry showed the number of TLR4 positive neuron in CA3 area at 1, 6, 12, 24, 48 h and 7, 10, 30, 50 d after SE was higher than that in the control group (P < 0.05, for all), but showed no significant difference at 0 h after SE (P = 0.326). There was no significant difference between LiCl group and model group at 0 h after SE (P = 0.451). The difference in CA1 and CA2 area in different groups was not statistically significant (P > 0.05). Conclusion TLR4 protein was mainly expressed in cytoplasm ofpyramidal cells in CA3 area of hippocampus. TLR4 protein expression in the hippocampus was increased in varying degrees at different observation time points after SE, indicating that TLR4 may play an important role in the development of epilepsy. doi：10.3969/j.issn.1672-6731.2013.12.009