The expression of hypoxia‐inducible factor‐1 alpha in primary reproductive organs of the female yak (Bos grunniens) at different reproductive stages

Abstract

The yak (Bos grunniens) is the most important livestock animal in high-altitude regions owing to its prominent adaptability to cold conditions, nutritional deficiencies and hypoxia. The reproductive organs exhibit different histological appearances and physiological processes at different reproductive stages. Hypoxia-inducible factor-1 alpha (HIF-1α) is the regulatory subunit of HIF-1 that crucially regulates the response to hypoxia in mammalian organisms. The goal of our study was to investigate the expression and distribution of HIF-1α in the primary yak reproductive organs at different reproductive stages. Samples of the ovary, oviduct and uterus of 15 adult female yaks were collected and used in the experiment. The expression and localization of HIF-1α proteins and mRNA were investigated using quantitative real-time polymerase chain reaction (qRT-PCR), Western blot (WB) and immunohistochemistry (IHC). The results indicated that the expression of HIF-1α protein in the ovary was higher during the luteal phase than during the follicular phase and gestation period (p < .05). In the oviduct, HIF-1α protein was also more highly expressed during the luteal phase than during the follicular phase and gestation period (p < .01). However, in the uterus, the HIF-1α protein had stronger expression during the gestation period than during the follicular phase (p < .01) and luteal phase (p < .05). The expression of HIF-1α mRNA was similar to that of its protein. Immunohistochemical analysis revealed intense immunostaining of HIF-1α proteins in the follicular granulosa cells, granular luteal cells, villous epithelial cells of the oviduct, endometrial glandular epithelium and luminal epithelium, foetal villous trophoblast, and epithelia of caruncular crypts. This study showed that the expression of HIF-1α in the ovary, oviduct and uterus varies according to the stage of the reproductive cycle. This implies that HIF-1α plays an important role in regulating the stage-specific physiological function of yak reproductive organs under hypoxic environments.

Study on the HIF ‐1α regulated by glycolytic pathways and mitochondrial function in yaks of different altitudes during postmortem aging

“…However, since mitochondrial functions still existed under hypoxic conditions, they could still affect energy metabolism (Matarneh et al, 2018; Wu et al, 2020). So far, HIF‐1α was studied for medical, biomedical, and biochemical purposes, but recently, it attracted the attention of meat specialists due to its regulatory role in postmortem meat quality and aging (Fan et al, 2020). Gao et al (2019) found that HIF‐1α expression in yak and beef was significantly different at different altitudes, and that the higher the altitude, the more severe the hypoxia, and the higher the expression of HIF‐1α.…”

Interaction networks between the Fallopian tubes and the embryo in human tubal pregnancy: Current knowledge and perspectives

“…62 HIF-1α is located in the yak oviduct, and its expression level varies according to the reproductive cycle stage. 63 Cigarette smoking has negative effects via HIF-1α to induce marked cilia loss in the rat oviduct. 64 However, the picture of HIF-1α in the human Fallopian tubes is still unclear due to the gaps in our own understanding of the molecular details of the HIF-1α/VEGF signaling pathway in tubal pregnancy.…”

Expression and distribution patterns of VEGF, TGF‐β1 and HIF‐1α in the ovarian follicles of Tibetan sheep

“…In mammals, known cellular signalling pathways such as PI3K/AKT, AKT/mTOR, TGF‐β and insulin growth factor (IGF) signalling regulated follicular development (Ernst et al., 2017). Another study has reported that there was HIF‐1α expression in the ovaries, indicating that HIF‐1α is involved in physiological function regulation in Yaks (Fan et al., 2020). TGF‐β 1 is an important growth factor that affects ovarian functions such as follicular development, steroidogenesis, ovulation, luteinisation and female fertility, among others (Knight & Glister, 2006).…”