Expression And Distribution Of LRP6 And VEGFR2 In Lungs Of Different Age Yak

The purpose of this study was to explore the expression and localization of LRP6 and VEGFR2 in the lung tissues of calves of different ages,and to elucidate the possible role of LRP6 and VEGFR2 in the adaptive structure of hypoxia in calf lungs.Newborn(1-7 days old,n=5),juvenile(5-6 months old,n=5),adult(3-6 years old,n=5)and old(7-10 years old,n=5)healthy yak lung tissue samples were selected for further study of relevant factors.Firstly,the LRPP6 and VEGFR2 gene sequences of calf were cloned by RT-PCR,and related bioinformatics analysis was performed.Then,quantitative PCR,enzyme-linked immunosorbent assay and Western-blot experiment were used to explore different ages from mRNA and protein.The expression of LRP6 and VEGFR2 in the yak lungs;Finally,the exact distribution and expression levels of LRP6 and VEGFR2 in lungs of different ages were studied using immunohistochemistry.The results show: 1.Using RT-PCR technology to clone the LRP6 and VEGFR2 gene sequences of yak and carry out related bioinformatics analysis,the results are as follows: The yak LRP6 gene was cloned(GenBank accession number: MF776096),and the open reading frame length was 624 bp.Start codon at 41 bp and the stop codon at 664 bp,encoding 207 amino acids.Homology analysis and phylogenetic tree showed that the calf LRP6 gene had similar evolutionary levels with wild yak,North American yak and sheep,and was far from the evolutionary level of human,macaque and cynomolgus monkeys.The yak VEGFR2 gene(GenBank accession number: MF590245)was cloned and its open reading frame length was 312 bp,the start codon was at 96 bp,and the stop codon was at 407 bp,encoding 103 amino acids.Homology analysis and phylogenetic tree indicated that the yak VEGFR2 gene was similar to the evolutionary levels of the bovine calf,domestic bovine and wild yak,and was far from the mouse,brown rat and human.2.LRP6 and VEGFR2 mRNA and protein expression patterns were the same in yak lungs,Expression from newborn to the old showed an increasing trend.There was no significant difference in the expression of LRP6 and VEGFR2 between the adult and juvenile old yaks(P>0.05).The differences in the expression levels of the dult,juvenile and old yak were significant(P<0.05).The difference between the expression levels of the newborn and old yak was significant(P<0.05).The expression of LRP6 and VEGFR2 mRNA in yaks was mainly expressed in the lungs of elderly yaks.The other groups had a small amount of expression,which may be related to the growth regulation mechanism of calves.3.The LRP6 was mainly distributed in the lungs of branches and their branches epithelial cells and alveolar type Ⅱ cells and the expression was stronger;the expression of pulmonary vascular endothelial cells and vascular wall smooth muscle cells was weak.The VEGFR2 was mainly distributed in the epithelial cells of the bronchial lung and its branches,wall smooth muscle cells and alveolar septum and alveolar typeⅠcells and the expression was stronger;the expression of pulmonary vascular endothelial cells and smooth muscle cells was weak.These two factors may be involved in the formation of the structure of the lung airways and pulmonary arteries in calves.