背景:不孕症是一个日益严重的全球健康问题,影响着全世界数百万对夫妇。在几个因素中,体重过重会对生殖功能产生不利影响。瘦素是一种众所周知的脂肪因子,可作为肥胖和生育能力之间的内分泌信号。然而,高瘦素水平对女性生殖影响的确切机制尚不清楚。
方法:通过回交产生过表达瘦素(‰)的转基因猪,并筛选瘦素过表达。增长曲线,脂肪沉积,繁殖性能,凋亡,血清激素和胆固醇的产生,RNA测序,和单核RNA测序(snRNA-seq)的瘦素过表达猪和野生型组进行了评估。
结果:获得了过表达瘦素的转基因猪,表现出显著减轻的体重,身体尺寸,和背部脂肪厚度。这些猪表现为青春期晚期(330±54.3vs.155±14.7天),以发情间间隔增加为特征的不规则发情行为(29.2±0vs.21.3±0.7天),和更多的交配直到怀孕(至少3次)。瘦素猪的这种生殖损害与以FSH水平升高为特征的激素失衡有关。LH,催乳素,E2、P4和TSH,类固醇生成改变,如血清胆固醇酯水平升高以及类固醇生成标志物(StAR,CYP19A),和卵巢功能障碍表现为中性粒细胞浸润和卵巢中caspase-3阳性细胞的低表达。此外,卵巢的大量RNA测序还显示嗜中性粒细胞浸润,随后炎症相关基因上调。此外,snRNA-seq反映了瘦素过表达引发的免疫反应,抑制卵泡发育和黄体化,导致卵巢代谢功能障碍和激素失衡。
结论:低体重的瘦素过表达猪对繁殖性能有不利影响。导致青春期延迟,不规则的动情周期,降低了育种效率。这与代谢失衡有关,增强的免疫反应,改变卵巢功能.本研究为瘦素潜在的复杂机制提供了理论依据,和使用瘦素过度表达的母猪不育症。
BACKGROUND: Infertility is a growing global health concern affecting millions of couples worldwide. Among several factors, an extreme body weight adversely affects reproductive functions. Leptin is a well-known adipokine that serves as an endocrine signal between adiposity and fertility. However, the exact mechanisms underlying the effects of high leptin level on female reproduction remain unclear.
METHODS: Transgenic pigs overexpressing leptin (♀) were produced by backcrossing and screened for leptin overexpression. The growth curve, fat deposition, reproductive performance, apoptosis, serum hormones and cholesterol production, RNA sequencing, and single-nucleus RNA sequencing (snRNA-seq) of the leptin-overexpressing pigs and wild-type group were evaluated.
RESULTS: Transgenic pigs overexpressing leptin (♀) were obtained, which exhibited significantly reduced body weight, body size, and back fat thickness. These pigs manifested a late onset of puberty (330 ± 54.3 vs. 155 ± 14.7 days), irregular estrous behavior characterized by increased inter-estrous interval (29.2 ± 0 vs. 21.3 ± 0.7 days), and more number of matings until pregnancy (at least 3 times). This reproductive impairment in leptin pigs was related to hormonal imbalances characterized by increased levels of FSH, LH, prolactin, E2, P4, and TSH, altered
steroidogenesis such as increased levels of serum cholesterol esters along with steroidogenic markers (StAR, CYP19A), and ovarian dysfunctions manifested by neutrophilic infiltration and low expression of caspase-3 positive cells in the ovaries. Moreover, bulk RNA sequencing of the ovaries also revealed neutrophilic infiltration followed by upregulation of inflammation-related genes. Furthermore, snRNA-seq reflected that leptin overexpression triggered immune response, suppressed follicle development and luteinization, resulting in metabolic dysfunction and hormone imbalance in the ovary.
CONCLUSIONS: Low body weight in leptin overexpressing pigs adversely affects the reproductive performance, causing delayed puberty, irregular estrous cycles, and reduced breeding efficiency. This is linked to metabolic imbalances, an increased immune response, and altered ovarian functions. This study provides a theoretical basis for the complex mechanisms underlying leptin, and infertility by employing leptin-overexpressing female pigs.