Characterization Of The Arterial Architecture Of The Uterine Caruncle In Yaks At Different Periods And Expression Of Angiogenesis-related Regulators

The occurrence,changes,and distribution of arterioles in the uterine caruncle of yaks in different periods and the expression of angiogenesis-related regulatory factors play an important role in the reproductive performance of yaks.In this study,we used the vascular casting technique to make stereotypes of the uterus and arterioles of the uterine caruncle in pregnant and non-pregnant yaks,observed the shape and distribution of the arterioles of the uterine caruncle,determined the number of branches of the arterioles of the uterine caruncle,and compared the differences of the arterioles of the uterus and the number of branches in different periods.Immunohistochemistry,real-time quantitative PCR(RT-q PCR),and western blot were also used to study the vascular endothelial growth factor(VEGF),vascular endothelial growth factor(VEGF),vascular endothelial growth factor(VEGF),and vascular endothelial growth factor(VEGF)in the yak.growth factor(VEGF),angiopoietin-1(Ang-1),epidermal growth factor(EGF),and its receptor(EGFR)in uterine caruncle tissues at different times The genes and proteins of EGF and its receptor(EGFR)were localized and quantified,and their differential expression was analyzed to investigate their relationship with the angiogenesis of the yak uterine meatus and to analyze their correlation with the reproductive performance of yaks.Key findings from this study include the following:1.The vascular casting of the uterus and her caruncular artery was successfully done using the vascular casting technique.It was found that the uterine artery originated from the abdominal aorta to the 1/3rd of the uterine artery,where two branches emerged,the superior and inferior branches,and both the superior and inferior branches continued to send out new branches to the uterine horn.The arcuate artery(2nd level branch)and its closely coiled,wavy 3rd～4th level branches accompanying the line finally anastomose to form a hollow tubular vascular network.3rd–4th level branches in the inner side of the vascular network branch out into small waves or dendritic vascular clusters convex to the inner side to supply blood to the uterine horn and the inner wall of the uterus.The arcuate artery’s main trunk moves in a "U" zigzag pattern and extends on the bottom or both sides of the "U" shape in vertical or oblique upward radiating(mildly curving)or dendritic branches to form a vascular network that extends into the uterine meats.The branches are initially spiral and twisted and then decrease near the end of the tree.2.A relative examination of examples from the gestational and nonpregnant periods uncovered a critical expansion in the number and length of grade 3～4 vascular branches in the uterus and its meatus of yaks during pregnancy,a diminishing in helicity,huge changes looking like the arcuate supply routes and the vessels fanning out the arcuate corridors,and an expansion in the twisting arterioles of the uterine blood vessel vascular organization.We counted 45±5.29 arciform supply routes,4.80±0.92 tertiary branches,and 18±3.62 little parts of the fourth request,more than during the non-gestational period(P<0.05).In the non-pregnant period,level 3 branches on every "U" twist were essentially situated at the sides of the curve,and the majority of them began to show up at the second twist of the primary trunk.During pregnancy,the number of branches expanded to 3～4tertiary branches,chiefly on the horizontal parts of the twist,and the winding parts of level3 showed up at the primary curve of the principal trunk.3.The IHC results showed that VEGF,Ang-1,EGF,and EGFR were similarly distributed in yak follicular,luteal,and gestational uterine caruncle tissues,mainly in the cytoplasm of the mucosal epithelium,the cytoplasm within the lumen of the uterine glands,and lymphocytes.The cytoplasm of the mucosal epithelium,the cytoplasm in the lumen of the glandular ducts,and the cytoplasm around the blood vessels showed strong positive expression,while the lymphocytes were positive and none of the negative controls were expressed.4.The results of RT-q PCR demonstrated differences in the expression of VEGF,Ang-1,EGF,and EGFR genes in yak follicular,luteal,and gestational carton tissues.m RNA expression of VEGF was highest in the gestational phase,followed by the luteal phase,and lowest in the follicular phase,the expression of VEGF m RNA was significantly higher from the follicular phase to the luteal phase and then to the gestational phase(P<0.05).m RNA Ang-1 was similar in expression to VEGF(P<0.05).The relative expression of EGF m RNA was significantly higher in the luteal phase than in the follicular phase and gestational phase(P<0.05).the relative expression of EGFR m RNA was significantly higher in the follicular phase than in the luteal phase and gestational phase(P<0.05).5.The results of Western blot showed that the expression of proteins VEGF,Ang-1,EGF,and EGFR differed in the uterine caruncle of yaks at different times.Among them,VEGF and Ang-1 proteins were highest in gestation,followed by the luteal phase,and lowest in the follicular phase,and there was a significant difference before the three(P<0.05).The EGF protein content was highest in gestation,followed by the follicular phase,and lowest in the luteal phase,and there was a significant difference between the three(P<0.05).The protein content of EGFR was significantly higher during pregnancy compared to the follicular and luteal phases(P<0.05).In conclusion,VEGF,Ang-1,EGF,and EGFR were expressed in the follicular phase,luteal phase,and gestational phase of the yak uterus and its caruncle under the present experimental conditions,and there were significant differences,with the highest protein expression in the gestational phase.It is hypothesized that the expression of VEGF,Ang-1,EGF,and EGFR is closely related to angiogenesis,which is important for the regulation and maintenance of reproductive physiological activities in female yaks.The expression of VEGF,Ang-1,EGF,and EGFR is presumed to be closely related to angiogenesis,which is important for the regulation and maintenance of reproductive physiology in female yaks.