Singh Jai, Paul A, Thakur N, Yadav V P, Panda R P, Bhure S K, Sarkar M
Physiology & Climatology, Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh 243122, India.
Biochemistry Section, Indian Veterinary Research Institute, Izatnagar, Bareilly, Uttar Pradesh 243122, India.
Anim Reprod Sci. 2015 Jul;158:31-52. doi: 10.1016/j.anireprosci.2015.04.006. Epub 2015 Apr 25.
The present study aimed to determine the expression of insulin like growth factor (IGF) genes in the bubaline ovarian follicles and modulatory role of IGF-I on progesterone production from granulosa cells (GC) of pre-ovulatory follicle in vitro. According to size, follicles were classified into four groups: GI (small), GII (medium), GIII (large) and GIV (preovulatory). All IGF genes were expressed in both GC and theca interna (TI) cells. The relative expression of IGF-I and IGF receptor I (IGFR-I) genes increased with follicle size and was greatest in the pre-ovulatory follicle (P<0.05). Expression of IGF-II and IGFR-II genes was minimal in GC but was readily detected in TI cells. In TI cells, the gene expression was greater in medium and large as compared to small and pre-ovulatory follicles. The expression of all binding protein (IGFBP) genes was detected in both GC and TI cells. Expression of IGFBP-3 gene increased with follicle size and was greatest in pre-ovulatory follicles (P<0.05). The expression of IGFBP-2 and IGFBP-4 was less in pre-ovulatory follicles but expression of IGFBP-5 and IGFBP-6 genes were greater at this stage. The GC culture was conducted for three time durations and with three doses of IGF-I. Expression of steroidogenic genes (StAR, CYP11A1, HSD3B) and progesterone concentration were increased in a dose and time dependent fashion. The present study, therefore, provided evidence of an autocrine/paracrine role of IGFs in follicular development and a stimulatory role of IGF1 in steroid production in GC of preovulatory follicles in the bubaline species.
本研究旨在确定胰岛素样生长因子（IGF）基因在水牛卵巢卵泡中的表达，以及IGF-I对体外排卵前卵泡颗粒细胞（GC）孕酮分泌的调节作用。根据大小，卵泡分为四组：GI（小）、GII（中）、GIII（大）和GIV（排卵前）。所有IGF基因在GC和卵泡内膜（TI）细胞中均有表达。IGF-I和IGF受体I（IGFR-I）基因的相对表达随卵泡大小增加而升高，在排卵前卵泡中最高（P<0.05）。IGF-II和IGFR-II基因在GC中的表达最低，但在TI细胞中易于检测到。在TI细胞中，与小卵泡和排卵前卵泡相比，中卵泡和大卵泡中的基因表达更高。在GC和TI细胞中均检测到所有结合蛋白（IGFBP）基因的表达。IGFBP-3基因的表达随卵泡大小增加而升高，在排卵前卵泡中最高（P<0.05）。IGFBP-2和IGFBP-4在排卵前卵泡中的表达较少，但IGFBP-5和IGFBP-6基因在该阶段的表达较高。对GC进行了三个时间段和三种剂量IGF-I的培养。类固醇生成基因（StAR、CYP11A1、HSD3B）的表达和孕酮浓度呈剂量和时间依赖性增加。因此，本研究提供了证据，证明IGF在卵泡发育中具有自分泌/旁分泌作用，以及IGF1对水牛排卵前卵泡GC中类固醇生成具有刺激作用。
