Soni N, Pandey A K, Kumar A, Verma A, Kumar S, Gunwant P, Phogat J B, Kumar V, Singh V
Department of Veterinary Gynaecology and Obstetrics, Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar 125004, India.
Department of Veterinary Clinical Complex, Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar 125004, India.
Domest Anim Endocrinol. 2020 Jul;72:106371. doi: 10.1016/j.domaniend.2019.06.003. Epub 2019 Jul 3.
High ambient temperature exhibits a retrograde effect on buffalo reproduction because of heat stress. Moreover, melatonin is known to regulate reproductive changes in seasonally reproductive animals by binding to high affinity, G protein-coupled receptors. The MTNR1A gene is a prime receptor, mediating the effect of melatonin at the neuroendocrine level to control seasonal reproduction. In sheep, the role of melatonin is well known; however, studies have not been conducted in buffalo to determine its effect during favorable and unfavorable breeding seasons. Therefore, the present study aimed to (1) determine the expression of MTNR1A, ERα, ERβ, and PR gene transcripts in the ovarian follicles of buffalo during the summer and winter seasons and (2) analyze melatonin, 17β-estradiol, and progesterone concentrations in the follicular fluid of buffalo during both seasons. Murrah buffalo ovaries were collected during both the summer (May-June) and winter (December-January) seasons. All visible ovarian follicles were allocated into one of three groups: (1) small (8-9.9 mm); (2) medium (10-11.9 mm); and (3) large (12-14 mm). Follicular fluid was aspirated from each group of follicles for hormone analyses. The granulosa cells were processed for RNA extraction. Furthermore, they were subjected to real-time quantitative PCR to analyze the expression (relative quantification) of MTNR1A, ERα, ERβ, and PR in each follicular group. The expression of MTNR1A gene transcript decreased with the increasing size of the follicle and intrafollicular melatonin concentration. Expression of ERα and PR remained unaffected by the season and was similar (P > 0.05) in all groups. Expression of ERβ was higher (P < 0.05) in summer than winter; nevertheless, small-sized follicles from the summer exhibited higher (P < 0.05) expressions than medium- and large-sized follicles. The overall intrafollicular melatonin concentration was positively correlated (P < 0.05) with 17β-estradiol and progesterone concentrations. In conclusion, the decreased expression of MTNR1A and increased concentration of intrafollicular melatonin with the increasing size of the follicle indicates a probable role in folliculogenesis and ovulation in buffalo.
由于热应激，高环境温度对水牛繁殖呈现逆行效应。此外，已知褪黑素通过与高亲和力的G蛋白偶联受体结合来调节季节性繁殖动物的生殖变化。MTNR1A基因是主要受体，介导褪黑素在神经内分泌水平的作用以控制季节性繁殖。在绵羊中，褪黑素的作用是众所周知的；然而，尚未在水牛中进行研究以确定其在有利和不利繁殖季节的影响。因此，本研究旨在：（1）确定夏季和冬季水牛卵巢卵泡中MTNR1A、ERα、ERβ和PR基因转录本的表达；（2）分析两个季节水牛卵泡液中褪黑素、17β-雌二醇和孕酮的浓度。在夏季（5月至6月）和冬季（12月至1月）收集摩拉水牛的卵巢。所有可见的卵巢卵泡被分为三组之一：（1）小卵泡（8 - 9.9毫米）；（2）中卵泡（10 - 11.9毫米）；（3）大卵泡（12 - 14毫米）。从每组卵泡中抽吸卵泡液进行激素分析。对颗粒细胞进行RNA提取。此外，对其进行实时定量PCR以分析每个卵泡组中MTNR1A、ERα、ERβ和PR的表达（相对定量）。MTNR1A基因转录本的表达随着卵泡大小和卵泡内褪黑素浓度的增加而降低。ERα和PR的表达不受季节影响，在所有组中相似（P>0.05）。ERβ的表达在夏季高于冬季（P<0.05）；然而，夏季的小卵泡比中卵泡和大卵泡表现出更高的表达（P<0.05）。卵泡内褪黑素的总体浓度与17β-雌二醇和孕酮浓度呈正相关（P<0.05）。总之，MTNR1A表达的降低以及卵泡内褪黑素浓度随卵泡大小增加表明其在水牛卵泡发生和排卵中可能发挥作用。
