An MRI study on abnormal hippocampus related structure and functional connectivity in pilocarpine-induced temporal lobe epilepsy rats

Abstract

Objective To study the abnormal hippocampal structural and functional connectivity in pilocarpine-induced temporal lobe epilepsy (TLE) rats. Methods Thirty SD rats were randomized into TLE group (n=20) and control group (n=10). Lithium-pilocarpine (LIP) was injected intraperitoneally in rats in the TLE group, and saline instead of pilocarpine was treated in the control group. Six weeks later, rats were received 7.0-tesla T MRI scanning for structural and functional images. The volume of hippocampal gray matter volume and dorsal hippocampus related functional connectivity were compared between the two groups. Results Immediately after LIP treatment, 12 rats in the TLE group exhibited status epilepticus. Six weeks later, spontaneous seizures were observed in 10 of the 12 rats in the TLE group were observed spontaneous seizures. The volumes of hippocampal gray matter volumes in the TLE and control groups were 102.51±1.97 mm3 and 85.76±1.62 mm3, respectively; significant differences wasere noted between the two groups(P<0.05). As compared to controls, the rats in the TLE group revealed decreased dorsal hippocampus related connectivity to the ipsilateral amygdala and the ipsilateral ventral hippocampus(P<0.05), and increased connectivity to the contralateral cortex(P<0.05). Conclusions In choronic LIP-TLE rats, hippocampal gray matter structures wereas impaired., and The functional connection in hippocampus-limbic system was diminished, while that in and hippocampus-cortex functional networks was enhancedere also abnormal. Key words: Epilepsy; Magnetic resonance imaging; Hippocampus; Rats