Immunohistochemical assessment of intrinsic and extrinsic markers of hypoxia in reproductive tissue: differential expression of HIF1α and HIF2α in rat oviduct and endometrium

Abstract

Hypoxia is thought to be critical in regulating physiological processes within the female reproductive system, including ovulation, composition of the fluid in the oviductal/uterine lumens and ovarian follicle development. This study examined the localisation of exogenous (pimonidazole) and endogenous [hypoxia inducible factor 1α and 2α (HIF1α, -2α), glucose transporter type 1 (GLUT1) and carbonic anhydrase 9 (CAIX)] hypoxia-related antigens within the oviduct and uterus of the rat reproductive tract. The extent to which each endogenous antigen co-compartmentalised with pimonidazole was also assessed. Female Wistar Furth rats (n = 10) were injected intraperitoneally with pimonidazole (60 mg/kg) 1 h prior to death. Reproductive tissues were removed immediately following death and fixed in 4% paraformaldehyde before being embedded in paraffin. Serial sections were cut (6–7 μm thick) and antigens of interest identified using standard immunohistochemical procedures. The mucosal epithelia of the ampulla, isthmus and uterus were immunopositive for pimonidazole in most sections. Co-compartmentalisation of pimonidazole with HIF1α was only expressed in the mucosa of the uterus whilst co-compartmentalisation with HIF2α was observed in the mucosa of the ampulla, isthmus and uterus. Both GLUT1 and CAIX were co-compartmentalised with pimonidazole in mucosa of the isthmus and uterus. This study confirms that mucosal regions of the rat oviduct and uterus frequently experience severe hypoxia and there are compartment specific variations in expression of endogenous hypoxia-related antigens, including the HIF isoforms. The latter observation may relate to target gene specificity of HIF isoforms or perhaps HIF2α’s responsiveness to non-hypoxic stimuli such as hypoglycaemia independently of HIF1α.

Curcumin ameliorates insulin signalling pathway in brain of Alzheimer’s disease transgenic mice

“…An IHC staining technique was used to examine the number of positive-stained neurons, including InR, IRS-1, PI3K, p-PI3K, AKT and p-AKT. 14 The paraffin sections were kept in a 56°C oven for 1 h. Then, they were moved into p-xylene1 and p-xylene2 in sequence and stayed there for 20 min. Next, the slices were placed in gradient 100%, 95%, 80% and 70% alcohol for 3-5 min, and then they were placed in distilled water.…”

Different Expression of Hypoxic and Angiogenic Factors in Human Endometriotic Lesions

“…[4][5][6] Hypoxia inducible factor 1a (HIF-1a) and HIF-2a are known to be stabilized at different oxygen levels and to have different temporal responses 7 and are expressed in human and rat endometrium. 8,9 Expression of HIF-1a mRNA was observed in eutopic endometrium of women with endometriosis 10 but not in endometriotic tissue, 11 while no data about HIF-2a expression in endometriotic lesions are referred.…”

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

“…In very early studies, the low O 2 concentration status of the oviductal lumen was examined using oxygen probe recordings during the menstrual or oestrous cycle stages of monkeys, hamsters and rabbits (Fischer & Bavister, 1993;Mastroianni & Jones, 1965). In addition, Gillies et al have also confirmed that mucosal regions of the rat oviduct frequently experience severe hypoxia and that there are compartment-specific variations in the expression of endogenous hypoxia-related antigens, including the HIF isoforms (Gillies, Robinson, McPhail, Carter, & Murray, 2011). Most recently, He et al (2020) found that higher mRNA levels of HIF-1α and HIF-2α occur in the oviduct and anterior pituitary compared with the hypothalamus, ovary and uterus in yak, and both of these are higher in these organs of yak than in cattle.…”