| Other Abstract | Objective: To explore the mechanism of missed abortion, the contents of serum &beta-hCG, VEGF and the expression levels of VEGF-MEK/ERK signaling pathway and trophoblast cell apoptosis related factors of villous tissues were measured and analyzed.
Methods: (1)Serum specimens and villous tissue specimens were collected from 12 cases of missed abortion and 12 termination of pregnancy by induced abortion due to unintended pregnancy in normal pregancy. All subjects were in the same age group, at the same gestational week, and had no history of exposure to occupational hazards. (2)Radioimmunoassay was used to detect &beta-hCG levels in serum of the two groups. (3)Enzyme-linked immunosorbent assay was used to detect VEGF levels in serum. (4)Hematoxylin-eosin sections of villous tissue were prepared and the histopathological changes of villous tissue were observed by light microscopy. (5)Immunohistochemistry CD34 positioning was used to detect the villous angiogenesis. (6)The mRNA expression levels of VEGF, VEGFR2, RAS, MEK1/2 and ERK1/2 related genes in villi, as well as the mRNA expression levels of apoptotic genes Bcl-2, Bax, Cyt c and Casepase 3 was detected by qRT-PCR. (7)The expression levels of VEGF-MEK/ERK signaling pathway related proteins including VEGF, VEGFR2, RAS, MEK1/2, p-MEK1/2, ERK1/2, p-ERK1/2 and the expression levels of apoptosis-related proteins Bcl-2, Bax, Cyt c and Casepase 3 were detected by Wes Simple Western system.
Results: (1)The content of &beta-hCG and VEGF in serum: The missed abortion group of serum &beta-hCG, VEGF levels were lower than normal pregnancy group (P <0.05). (2)The pathological changes of villi tissues in the two groups: the trophoblast of the villi tissues in the missed abortion was significantly thinner, the number of cells was reduced, the cell structure was disordered, and part of the trophoblast cells were absent. (3)The angiogenesis of villi: In missed abortion group, the blood vessels in the villi interstitium were small, the vessel lumen was narrow, and the number of vessels was decreased obviously. The microvascular count results showed that the microvascular density in the villi of the missed abortion group was lower than the normal early pregnancy group (P <0.05). (4)Expression of VEGF-MEK/ERK signaling pathway related factors in villi: The expression levels of VEGF, VEGFR2, MEK1/2 and ERK1/2 mRNA in the villi of the missed abortion group were lower than the normal early pregnancy group (P <0.05)The expression levels of VEGF, RAS, p-MEK1/2 and p-ERK1/2 proteins and the p-MEK/MEK and p-ERK/ERK ratios in the villi of the missed abortion group were lower than the normal early pregnancy group (P <0.05). (5)The expression of apoptosis-related factors in trophoblast cells in villi: the expression level of Bcl-2 mRNA in villi of the missed abortion group was lower than the normal early pregnancy group (P <0.05)The mRNA expression levels of Bax, Cyt c and Caspase 3 in the villi of the missed abortion group were higher than the normal early pregnancy group (P <0.05)The expression level of Bcl-2 protein in the villi of the missed abortion group was lower than the normal early pregnancy group (P <0.05)The expression levels of Bax/Bcl-2, Cyt c and Caspase 3 proteins in the villi of the missed abortion group were higher than the normal early pregnancy group (P <0.05). (6)The correlation analysis of VEGF and ERK1/2 protein expression level in villi tissue and villous microvessel density: In missed abortion group, the ERK1/2 protein expression level was positively correlated with villous microvessel density (r=0.909, P <0.05).
Conclusion: The &beta-hCG, VEGF levels in the serum were decreased, the expression of the VEGF-MEK/ERK signaling pathway was down-regulated, villi angiogenesis were reduced and mitochondrial apoptotic pathway was activated, villi angiogenesis and trophoblast dysfunction were impaired in early pregnancy, which may be an important mechanism for missed abortion. |
