Injury elicited increase in spinal cord neurosteroid content analyzed by gas chromatography mass spectrometry
Injury elicited increase in spinal cord neurosteroid content analyzed by gas chromatography mass spectrometry
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DOI：
10.1210/en.2005-0955
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发表时间：
2006-04-01
期刊：
影响因子：
4.8
通讯作者：
Guennoun, R
中科院分区：
文献类型：
--
作者：
Labombarda, F;Pianos, A;Guennoun, R
在成年雄性大鼠脊髓（SC）中研究了脊髓损伤（SCI）、去势和肾上腺切除术联合以及孕酮（PROG）治疗对神经类固醇水平和类固醇生成酶表达的影响。通过气相色谱/质谱法定量SC和血浆中的类固醇水平，并通过定量实时RT-PCR定量酶的mRNA。在横切后75 h SC中，双烯醇酮（PREG）、PROG、5 α-二氢孕酮、3 α，5 α-四氢孕酮的水平增加，而血浆中无显著增加。联合肾上腺切除术和性腺切除术后，显着水平的PREG和PROG仍然在SC中，这表明他们的本地生物合成。在肾上腺切除和性腺切除大鼠的SC中，SCI后24小时PREG增加，随后在75小时伴随其直接代谢产物PROG的增加。这些观察结果与PREG生物合成的连续增加及其在SC内响应于损伤而转化为PROG一致。然而，SCI后P450-侧链裂解和3 β-羟基类固醇脱氢酶/Delta 5-Delta 4异构酶mRNA水平无显著变化。SCI后系统性PROG治疗导致血浆和SC中PROG、5 α-二氢孕酮和3 α，5 α-四氢孕酮的非常大的增加。此外，在SC中检测到高水平的3 β，5 α-四氢孕酮，而它们的血浆水平几乎检测不到。由于SC中还原代谢物与PROG的比例是血浆中的65倍，因此还原代谢物似乎主要来源于局部生物合成。我们的研究结果强烈表明，当地生物合成的神经甾体在SC损伤的反应中发挥着重要作用。
The effects of spinal cord injury (SCI), combined with castration and adrenalectomy, and of progesterone (PROG) treatment on neurosteroid levels and steroidogenic enzyme expression were investigated in the adult male rat spinal cord (SC). Steroid levels were quantified by gas chromatography/ mass spectrometry in SC and plasma, and mRNAs of enzymes by quantitative real-time RT-PCR. The levels of pregnenolone (PREG), PROG, 5 alpha-dihydroprogesterone, 3 alpha,5 alpha-tetrahydroprogesterone increased in SC 75 h after transection without significant increase in the plasma. After combined adrenalectomy and gonadectomy, significant levels of PREG and PROG remained in the SC, suggesting their local biosynthesis. In the SC of adrenalectomized and gonadectomized rats, there was an increase of PREG 24 h after SCI, followed at 75 h by a concomitant increase in its direct metabolite, PROG. These observations are consistent with a sequential increase of PREG biosynthesis and its conversion to PROG within the SC in response to injury. However, no significant change in P450-side chain cleavage and 3 beta-hydroxysteroid dehydrogenase/Delta 5-Delta 4 isomerase mRNA levels was observed after SCI. Systemic PROG treatment after SCI, resulted in a very large increase in PROG, 5 alpha-dihydroprogesterone, and 3 alpha,5 alpha-tetrahydroprogesterone in both plasma and SC. Furthermore, high levels of 3 beta,5 alpha-tetrahydroprogesterone were detected in SC, whereas their plasma levels remained barely detectable. Because the ratio of reduced metabolites to PROG was 65-times higher in SC than in the plasma, it appears likely that reduced metabolites mainly originated from local biosynthesis. Our results strongly suggest an important role for locally biosynthesized neurosteroids in the response of the SC to injury.