Bataillard A, Blanc-Brunat N, Vivier G, Medeiros I, Zhang B L, Touraine J L, Sassard J
Département de Physiologie et de Pharmacologie Clinique, CNRS URA 1483, Lyon, France.
Am J Hypertens. 1996 Feb;9(2):171-7. doi: 10.1016/0895-7061(95)00255-3.
The aim of this study was to search for the possible mechanisms involved in the antihypertensive effect of neonatal thymectomy that we previously observed in Lyon hypertensive (LH) rats. To that end, we studied in LH and normotensive control (LN) rats the consequences of neonatal thymectomy on vascular reactivity, renal structure, and pressure-natriuresis. The increase in pressor responses to angiotensin I and phenylephrine noted in LH rats as compared to LN animals was abolished by neonatal thymectomy. Histological study showed that kidneys from LH rats exhibited arterial wall hypertrophy, segmental hyalinization of the glomeruli, and were infiltrated by mononuclear cells. All these features of kidney injury were reduced in neonatally thymectomized LH rats. Lastly, the responses of isolated perfused kidneys from LH rats to stepwise reductions in renal perfusion pressure differed from those of LN rats by decreased renal perfusion flow and natriuresis. Neonatal thymectomy tended to improve sodium excretion in parallel with a slight decrease in renal vascular resistances. It is concluded that the normalization of vascular responsiveness to vasoconstrictor factors, the alleviation of renal lesions and, to a lesser extent, the moderate improvement of pressure natriuresis may account, at least in part, for the antihypertensive effect of neonatal thymectomy in LH rats.
本研究的目的是探寻我们之前在里昂高血压（LH）大鼠中观察到的新生期胸腺切除术后的降压作用所涉及的可能机制。为此，我们在LH大鼠和正常血压对照（LN）大鼠中研究了新生期胸腺切除对血管反应性、肾脏结构和压力-利钠作用的影响。与LN大鼠相比，LH大鼠对血管紧张素I和去氧肾上腺素的升压反应增强，而新生期胸腺切除可消除这种增强作用。组织学研究表明，LH大鼠的肾脏表现出动脉壁肥厚、肾小球节段性玻璃样变，并伴有单核细胞浸润。新生期胸腺切除的LH大鼠肾脏损伤的所有这些特征均有所减轻。最后，LH大鼠离体灌注肾脏对肾灌注压逐步降低的反应与LN大鼠不同，表现为肾灌注流量和利钠作用降低。新生期胸腺切除倾向于改善钠排泄，同时肾血管阻力略有降低。结论是，血管对血管收缩因子反应性的正常化、肾脏病变的减轻以及在较小程度上压力-利钠作用的适度改善，可能至少部分解释了新生期胸腺切除对LH大鼠的降压作用。
