Expression pattern of Mical-1 in the temporal neocortex of patients with intractable temporal epilepsy and pilocarpine-induced rat model

Abstract

Mical-1 is a novel F-actin-disassembly factor that is critical in actin reorganization. It provides a molecular conduit through which actin reorganizes-a hallmark of cell morphological changes, including axon navigation. However, whether Mical-1 is involved in the epileptogenesis remains unknown. Here, we investigate Mical-1 expression pattern in patients with intractable temporal lobe epilepsy (TLE) and pilocarpine-induced rat model. We used double-labeled immunoflurescence, immunohistochemistry, and Western blotting to assess the location and expression of Mical-1 in temporal neocortex of patients with intractable TLE, and the expression pattern of Mical-1 at different time point in the hippocampus and temporal lobe cortex of the pilocarpine-induced rat model. Double-labeled immunofluorescence showed that Mical-1 was coexpressed with neuron-specific enolase (NSE) in the cytoplasm of neurons in temporal neocortex of patients with TLE and hippocampus of rat model. Faint and scattered immunoreactivity for Mical-1 in the neuron of temporal neocortex in TLE group, but strong immunoreactivity for Mical-1 was shown in control subjects. To quantitatively evaluate the Mical-1 immunoreactivity, we measured the mean optical density (OD) of Mical-1. In the hippocampus of pilocarpine-induced rat model, the OD values transient increased at 6 h after seizure then decreased from 1 day to 14 days, and returned to a subnormal level at 60 days. The lowest level of Mical-1 expression occurred at 14 days after seizure in the hippocampus. In the temporal lobe cortex of rat model, the OD values decreased at all time point after kindling compared to the normal group. Furthermore, our Western blot analysis confirmed these expression patterns of Mical-1 from latent stage to chronic stage. Our results indicate that in patients with TLE and pilocarpine-induced rat model, the expression of Mical-1 were followed a downtrend from the latent stage to chronic stage after seizure evoke. Thus, as an effect factor participated in F-actin disassemble, Mical-1 may associate with inner pathophysiological modulation in epilepsy.