Faculty of Veterinary and Animal Sciences, Mahasarakham University, Tambon Talaad, Amphur Muang, Mahasarakham 44000, Thailand.
Theriogenology. 2010 Jun;73(9):1257-66. doi: 10.1016/j.theriogenology.2009.12.005. Epub 2010 Feb 19.
The complex anatomy the of ovine cervix limits the success of transcervical artificial insemination in sheep, but Misoprostol (a PGE(1) analogue) relaxes the cervix and facilitates transcervical artificial insemination. However, the mechanism by which Misoprostol causes cervical relaxation is not known. This study examined if intra-cervical Misoprostol altered the hyaluronan content and the mRNA expression of COX-2, LHR, or FSHR in the cervix of the estrus ewe. Estrus was synchronized in cyclic ewes with progestagen pessaries and 48 h after sponge removal ewes were treated intra-cervically with 0 (controls), 200, or 400 microg Misoprostol. Hyaluronan content was determined by ELISA and mRNA expression of LHR, FSHR, and COX-2 was analyzed by in situ hybridization using digoxigenin-11-uridine-5'-triphosphate labeled riboprobes. The hyaluronan content of the cervix was significantly higher in sheep that received 200 (P<0.05) or 400 (P<0.05) microg Misoprostol compared to controls. Moreover, it was significantly (P<0.05) higher in the vaginal region compared to mid and uterine regions. Misoprostol increased (P<0.05) the mRNA expression of LHR and COX-2 but not FSHR. The expression for all three genes was highest in the vaginal region and lowest in uterine region. The luminal epithelium and circular smooth muscle layers had higher (P<0.05) expression for LHR, FSHR, and COX-2 mRNAs, and the sub-epithelial stroma had the lowest (P<0.05). We propose that the intra-cervical application of Misoprostol induces the mRNA expression of LHR, FSHR, and COX-2 through a positive feedback loop. The data suggest that softening of the cervix by Misoprostol is caused by an increase in the hyaluronan content of the cervix.
绵羊宫颈的复杂解剖结构限制了经宫颈人工授精的成功率，但米索前列醇（一种 PGE（1）类似物）可使宫颈松弛，从而促进经宫颈人工授精。然而，米索前列醇引起宫颈松弛的机制尚不清楚。本研究检测了经宫颈给予米索前列醇是否会改变发情母羊宫颈中的透明质酸含量以及 COX-2、LHR 或 FSHR 的 mRNA 表达。用孕激素阴道栓同步循环母羊发情，海绵取出后 48 小时，经宫颈给予 0（对照组）、200 或 400μg 米索前列醇。通过 ELISA 测定透明质酸含量，通过原位杂交分析用 DIG-11-尿嘧啶 5'-三磷酸标记的 RNA 探针分析 LHR、FSHR 和 COX-2 的 mRNA 表达。与对照组相比，接受 200（P<0.05）或 400（P<0.05）μg 米索前列醇的绵羊宫颈中的透明质酸含量显著增加。此外，阴道区的含量明显高于中、子宫区。米索前列醇增加（P<0.05）LHR 和 COX-2 的 mRNA 表达，但不增加 FSHR 的表达。这三个基因的表达在阴道区最高，在子宫区最低。腔上皮和环形平滑肌层的 LHR、FSHR 和 COX-2 mRNAs 表达较高（P<0.05），而黏膜下基质的表达较低（P<0.05）。我们提出，经宫颈给予米索前列醇通过正反馈环诱导 LHR、FSHR 和 COX-2 的 mRNA 表达。数据表明，米索前列醇使宫颈变软是由于宫颈透明质酸含量增加所致。
