Vio C P, Balestrini C, Recabarren M, Cespedes C
Departamento de Ciencias Fisiológicas, Facultad de Ciencias Biologicas, Pontificia Universidad Católica de Chile, Santiago.
Immunopharmacology. 1999 Oct 15;44(1-2):205-10. doi: 10.1016/s0162-3109(99)00091-0.
Prostaglandins are local mediators/modulators of kinin effects in the kidney. The prostaglandin G2/H2 synthase (cyclooxygenase, COX) is the key regulatory enzyme of prostanoid synthesis pathway. Two COX isoenzymes (constitutive or COX-1 and inducible or COX-2) have been described in the rat kidney. We have demonstrated the presence of COX-2 in a subset of thick ascending limb of Henle (TAL) cells in normal adult rats [Vio, C.P., Cespedes, C., Gallardo, P., Masferrer, J.L., 1997. Renal identification of cyclooxygenase-2 in a subset of thick ascending limb cells. Hypertension 30, 687-692]. The present work was designed to evaluate COX-2 during the postnatal development of the rat kidney. Kidneys from Sprague-Dawley rats were studied during postnatal days 5, 10, 15 days and adult (60 days) (n = 8 each group). Renal tissue was immunostained with specific antibodies against COX-2. COX-2 was observed exclusively in TAL. A small number of COX-2 cells were observed during early postnatal life, increasing from day 5 to 15, and decreasing thereafter to reach adult levels. During maximal expression, near 20% of TAL were COX-2 positive whereas in early postnatal period and adults, only 2% of TAL cells contain COX-2. This transient induction of COX-2 during development suggest that the enzyme is necessary for the postnatal development of the kidney. This change in COX-2 seems to correspond to a derepression of COX-2 gene expression secondary to low levels of glucocorticoids.
前列腺素是肾脏中激肽效应的局部介质/调节剂。前列腺素G2/H2合酶（环氧化酶，COX）是前列腺素合成途径的关键调节酶。在大鼠肾脏中已描述了两种COX同工酶（组成型或COX-1以及诱导型或COX-2）。我们已经证实在正常成年大鼠的髓袢升支粗段（TAL）细胞亚群中存在COX-2[维奥，C.P.，塞斯佩德斯，C.，加拉多，P.，马斯费雷尔，J.L.，1997年。肾髓袢升支粗段细胞亚群中环氧化酶-2的鉴定。《高血压》30，687 - 692]。本研究旨在评估大鼠肾脏出生后发育过程中的COX-2。对出生后第5天、第10天、第15天和成年期（60天）的斯普拉格-道利大鼠的肾脏进行研究（每组n = 8）。用针对COX-2的特异性抗体对肾组织进行免疫染色。仅在TAL中观察到COX-2。在出生后早期观察到少量COX-2细胞，从第5天到第15天增加，此后减少至成年水平。在最大表达期间，近20%的TAL为COX-2阳性，而在出生后早期和成年期，仅2%的TAL细胞含有COX-2。发育过程中COX-2的这种短暂诱导表明该酶对肾脏的出生后发育是必需的。COX-2的这种变化似乎对应于糖皮质激素水平低导致的COX-2基因表达的去抑制。
