Chun S Y, Eisenhauer K M, Kubo M, Hsueh A J
Department of Gynecology and Obstetrics, Stanford University School of Medicine, California 94305-5317, USA.
Endocrinology. 1995 Jul;136(7):3120-7. doi: 10.1210/endo.136.7.7540548.
A growing body of evidence suggests that intraovarian interleukin-1 beta (IL-1 beta) may play an intermediary role in the ovulatory process. Furthermore, induction of nitric oxide (NO) by IL-1 beta has been reported in a wide variety of tissues. As the majority of ovarian follicles undergo an atretic degeneration process involving apoptotic cell death, we set out to determine whether IL-1 beta rescues follicles from apoptosis and the possible involvement of NO. Preovulatory follicles obtained from PMSG-primed rats were cultured for 24 h in serum-free medium with or without hormone treatments. After culture, follicular apoptotic DNA fragmentation was analyzed by autoradiography of size-fractionated DNA labeled at 3'-ends with [32P]dideoxy-ATP. Follicular NO production was also determined by a colorimetric method. Treatment with IL-1 beta dose-dependently suppressed the spontaneous onset of apoptosis in cultured follicles, but stimulated NO production. In contrast, the addition of IL-1 receptor antagonist eliminated both effects of IL-1 beta, confirming receptor mediation. Follicles treated with sodium nitroprusside, a NO generator or an analog of cGMP, the second messenger for NO, also showed decreased follicle apoptosis. Moreover, the addition of NG-monomethyl-L-arginine, a NO synthase inhibitor, reversed both IL-1 beta stimulation of NO production and suppression of apoptosis, suggesting a mediatory role of NO in these IL-1 beta effects. Gonadotropins also prevent follicle apoptosis. Of interest, treatment with hCG stimulated NO production, and the hCG suppression of follicle apoptosis and stimulation of NO production were partially blocked by cotreatment with IL-1 receptor antagonist, indicating the mediation of endogenous IL-1 beta. Treatment with IL-1 beta also stimulated a small increase in the production of cAMP, estrogen, and progesterone. Taken together, these findings suggest that IL-1 beta is a survival factor for ovarian follicles, and its action is partially mediated via NO and cGMP generation. Moreover, part of the suppressive action of gonadotropins on follicle apoptosis is mediated by endogenously produced IL-1 beta.
越来越多的证据表明，卵巢内白细胞介素-1β（IL-1β）可能在排卵过程中起中介作用。此外，已有报道称IL-1β在多种组织中可诱导一氧化氮（NO）生成。由于大多数卵巢卵泡会经历一个涉及凋亡性细胞死亡的闭锁退化过程，我们着手确定IL-1β是否能使卵泡免于凋亡以及NO可能的参与情况。从经孕马血清促性腺激素（PMSG）预处理的大鼠获取的排卵前卵泡，在无血清培养基中进行培养24小时，有无激素处理。培养后，通过对用[32P]双脱氧三磷酸腺苷标记3'末端的大小分级DNA进行放射自显影分析卵泡凋亡性DNA片段化。卵泡NO生成也通过比色法测定。用IL-1β处理剂量依赖性地抑制培养卵泡中凋亡的自发发生，但刺激NO生成。相反，添加IL-1受体拮抗剂消除了IL-1β的两种作用，证实了受体介导。用硝普钠（一种NO供体）或cGMP（NO的第二信使）类似物处理的卵泡也显示卵泡凋亡减少。此外，添加NO合酶抑制剂NG-单甲基-L-精氨酸可逆转IL-1β对NO生成的刺激和对凋亡的抑制，表明NO在这些IL-1β作用中起中介作用。促性腺激素也可防止卵泡凋亡。有趣的是，用人绒毛膜促性腺激素（hCG）处理刺激NO生成，并且hCG对卵泡凋亡的抑制和对NO生成的刺激被与IL-1受体拮抗剂共同处理部分阻断，表明内源性IL-1β的介导作用。用IL-1β处理也刺激了环磷酸腺苷（cAMP）、雌激素和孕酮生成的小幅增加。综上所述，这些发现表明IL-1β是卵巢卵泡的存活因子，其作用部分通过NO和cGMP生成介导。此外，促性腺激素对卵泡凋亡的部分抑制作用是由内源性产生的IL-1β介导的。
