Supplementary Material for: Allopregnanolone and Pregnanolone Are Reduced in the Hippocampus of Epileptic Rats, but Only Allopregnanolone Correlates with Seizure Frequency

Background: Neurosteroids modulate epileptic activity by interacting with the γ-aminobutyric acid type A receptor, but their brain levels are still undetermined. Objectives: We aimed to establish neurosteroid levels in the neocortex and hippocampus by liquid chromatography/mass spectrometry in epileptic rats. Methods: Kainic acid-treated rats were continuously monitored up to 9 weeks to determine seizure frequency by video electrocorticography (n = 23) and compared to age-matched controls monitored in the same manner (n = 11). Results: Decreased allopregnanolone (–50%; p < 0.05, Mann-Whitney test) and pregnanolone levels (–64%; p < 0.01) were found in the hippocampus, whereas pregnenolone sulfate, pregnenolone, progesterone, and 5α-dihydroprogesterone were nonsignificantly reduced. No changes were found in the neocortex. Moreover, allopregnanolone (but not pregnanolone) levels were positively correlated with seizure frequency (r2 = 0.4606, p < 0.01). Conclusion: These findings indicate a selective reduction in hippocampal levels of 3α-reduced neurosteroids. This reduction was partially mitigated by seizures in the case of allopregnanolone.

背景：神经甾体（neurosteroids）通过与A型γ-氨基丁酸（γ-aminobutyric acid type A, GABAA）受体结合调控癫痫发作活动，但目前其脑内水平仍未明确。
研究目的：本研究旨在通过液相色谱-质谱联用法（liquid chromatography/mass spectrometry, LC-MS）测定癫痫模型大鼠新皮层与海马体中的神经甾体水平。
方法：本研究对海人酸（kainic acid, KA）造模的癫痫大鼠进行最长9周的持续监测，通过视频脑电监测（video electrocorticography, video-ECoG）统计其癫痫发作频率（n=23），并以相同监测方式处理的同龄对照大鼠作为对照（n=11）。
结果：在海马体中检测到别孕烷醇酮（allopregnanolone）水平降低50%（p<0.05，曼-惠特尼U检验），孕烷醇酮（pregnanolone）水平降低64%（p<0.01）；硫酸孕烯醇酮、孕烯醇酮、孕酮及5α-双氢孕酮的水平虽有下降，但差异无统计学意义。新皮层中未发现显著变化。此外，别孕烷醇酮（而非孕烷醇酮）的水平与癫痫发作频率呈正相关（决定系数r²=0.4606，p<0.01）。
结论：本研究结果表明，癫痫模型大鼠海马体中3α还原型神经甾体的水平呈现选择性降低；而就别孕烷醇酮而言，该水平降低可被癫痫发作部分缓解。