Objective:To discuss the effect of exosomes(Exos)loaded with microRNA-520a-5p(miR-520a-5p)on the pregnancy outcomes in fetal mice with intrauterine growth restriction(FGR),and to clarify its mechanism.Methods:The mouse placental mesenchymal stem cells(MSCs)were cultured in vitro and transfected with miR-520a-5p adenovirus vector(Ad-miR-520a-5p)to obtain the Exos with high miR-520a-5p load(miR-520a-5p-MSCs-Exos),which were then identified.The C57BL/6 mice were mated in cages at a female∶male ratio of 2∶1 to achieve successful pregnancy.Forty pregnant mice were divided into control group,FGR group,NC-MSCs-Exos group,and miR-520a-5p-MSCs-Exos group,with 10 mice in each group.Except for control group,the mice in other groups were exposed to excessive dexamethasone(DEX)during pregnancy to induce FGR models in the pregnant mice.The body weights of the fetal mice at birth and at 1,2,3,and 4 weeks after birth were detected;real-time fluorescence quantitative PCR(RT-qPCR)method was used to detect the expression levels of miR-520a-5p,DNA methyltransferase 3b(DNMT3b),and vascular endothelial growth factor(VEGF)mRNA in placenta tissue of the mice in various groups;Western blotting method was used to detect the expression levels of DNMT3b and VEGF proteins in placenta tissue of the mice in various groups;methylation-specific PCR(MSP)was used to analyze the methylation rates of VEGF promoter in placenta tissue of the mice in various groups;dual-luciferase reporter gene assay was used to verify the targeting relationship between miR-520a-5p and DNMT3b.Results:The results of transmission electron microscope(TEM)and nanoparticle tracking analysis(NTA)showed that the Exos were spherical with particle size concentrated near 100 nm;the Western blotting method results showed that the surface biomarkers CD63 and CD81 of Exos were positively expressed.The RT-qPCR results showed that compared with NC-MSCs-Exos and Ad-NC-MSCs-Exos,the expression level of miR-520a-5p in Ad-miR-520a-5p-MSCs-Exos was increased(P＜0.001).The differences in birth body weight and the body weights at 1,2,and 3 weeks after birth of the fetal mice among four groups were statistically significant(F=36.084,F=19.851,F=77.755,F=103.223;P＜0.001).Compared with control group,the birth body weight and the body weights at 1,2,and 3 weeks after birth of the fetal mice in FGR group were decreased(P＜0.05);compared with FGR group and NC-MSCs-Exos group,the birth body weight and the body weights at 1,2,and 3 weeks after birth of the fetal mice in miR-520a-5p-MSCs-Exos group were increased(P＜0.05).The One-way ANOVA results showed that the differences in the expression levels of miR-520a-5p,DNMT3b,and VEGF mRNA in placenta tissue of the mice among four groups were statistically significant(F=103.224,F=856.460,F=214.563;P＜0.001).The pairwise comparison between groups showed that compared with control group,the expression levels of miR-520a-5p and VEGF mRNA in placenta tissue of the mice in FGR group were decreased(P＜0.05),and the expression level of DNMT3b mRNA was increased(P＜0.05);compared with FGR group and NC-MSCs-Exos group,the expression levels of miR-520a-5p and VEGF mRNA in placenta tissue of the mice in miR-520a-5p-MSCs-Exos group were increased(P＜0.05),and the expression level of DNMT3b mRNA was decreased(P＜0.05).The One-way ANOVA results showed that the differences in the expression levels of DNMT3b and VEGF proteins in placenta tissue of the mice among four groups were statistically significant(F=245.601,F=149.360;P＜0.001).The pairwise comparison between groups showed that compared with control group,the expression level of DNMT3b protein in placenta tissue of the mice in FGR group was increased(P＜0.05),and the expression level of VEGF protein was decreased(P＜0.05);compared with FGR group and NC-MSCs-Exos group,the expression level of DNMT3b protein in placenta tissue of the mice in miR-520a-5p-MSCs-Exos group was decreased(P＜0.05),and the expression level of VEGF protein was increased(P＜0.05).The One-way ANOVA results showed that the difference in the methylation rate of VEGF promoter in placenta tissue of the mice among four groups was statistically significant(F=687.096,P＜0.001).The pairwise comparison between groups showed that compared with control group,the methylation rate of VEGF promoter in placenta tissue of the mice in FGR group was increased(P＜0.05);compared with FGR group and NC-MSCs-Exos group,the methylation rate of VEGF promoter in placenta tissue of the mice in miR-520a-5p-MSCs-Exos group was decreased(P＜0.05).Dual-luciferase reporter gene assay results showed that compared with miR-NC group,the luciferase activity in the cells containing DNMT3b-WT reporter vector in miR-520a-5p group was decreased(P＜0.05);compared with miR-NC group,the luciferase activity in the cells containing DNMT3b-MUT reporter vector in miR-520a-5p group had no change,no significant difference was observed(P＞0.05).Conclusion:The MSCs-derived Exos highly loaded with miR-520a-5p may improve the pregnancy outcomes of FGR fetal mice by targeting and down-regulating the expression of DNMT3b,inhibiting VEGF methylation,and promoting VEGF expression.

Objective:To evaluate the value of p16 INK4a detected by p16 INK4a immunostaining as a new generation of cervical cytology for primary screening and secondary screening in population-based cervical cancer screening, and in improving cytological diagnosis. Methods:Between 2016 and 2018, 5 747 non-pregnant women aged 25-65 years with sexual history were recruited and underwent cervical cancer screening via high-risk (HR)-HPV/liquid-based cytological test (LCT) test in Shenzhen and surrounding areas. All slides were immuno-stained using p16 INK4a technology, among them, 902 cases were offered p16 INK4a detection during primary screening, and the remaining 4 845 cases were called-back by the virtue of abnormal HR-HPV and LCT results for p16 INK4a staining. Participants with complete LCT examination, HR-HPV test, p16 INK4a staining and histopathological examination results were included in this study. The performance of p16 INK4a in primary and secondary screening, and in assisting cytology to detect high grade squamous intraepithelial lesion [HSIL, including cervical intraepithelial neoplasia (CIN) Ⅱ or Ⅲ] or worse [HSIL (CIN Ⅱ) + or HSIL (CIN Ⅲ) +] were analyzed. Results:(1) One-thousand and ninety-seven cases with complete data of p16 INK4a and histology were included. Pathological diagnosis: 995 cases of normal cervix, 37 cases of low grade squamous intraepithelial lesion (LSIL), 64 cases of HSIL and one case of cervical cancer were found. Among them, 65 cases of HSIL (CIN Ⅱ) + and 34 cases of HSIL (CIN Ⅲ) + were detected. The positive rate of p16 INK4a in HSIL (CIN Ⅱ) + was higher than that in CINⅠ or normal pathology (89.2% vs 10.2%; P<0.01). (2) p16 INK4a as primary screening for HSIL (CIN Ⅱ) + or HSIL (CIN Ⅲ) + was equally sensitive to primary HR-HPV screening (89.2% vs 95.4%, 94.1% vs 94.1%; P>0.05), but more specific than HR-HPV screening (89.8% vs 82.5%, 87.7% vs 80.2%; P<0.05). p16 INK4a was equally sensitive and similarly specific to cytology (≥LSIL; P>0.05). (3) The specificity of LCT adjunctive p16 INK4a for detecting HSIL (CIN Ⅱ) + or HSIL (CIN Ⅲ) + were higher than that of LCT alone or adjunctive HR-HPV ( P<0.01), while the sensitivity were similar ( P>0.05). (4) p16 INK4a staining as secondary screening: p16 INK4a was significantly more specific (94.1% vs 89.7%, 91.9% vs 87.4%; P<0.01) and comparably sensitive (84.6% vs 90.8%, 88.2% vs 91.2%; P>0.05) to cytology for triaging primary HR-HPV screening. HPV 16/18 to colposcopy and triage other HR-HPV with p16 INK4a was equally sensitive (88.2% vs 94.1%; P=0.500) and more specific (88.3% vs 83.0%; P<0.01) than HPV 16/18 to colposcopy and triage other HR-HPV with LCT≥ atypical squamous cells of undetermined significance (ASCUS), and the referral rate decreased (14.0% vs 19.4%; P=0.005). Conclusions:For primary screening, p16 INK4a is equally specific to cytology and equally sensitive to HR-HPV screening. p16 INK4a alone could be an efficient triage after primary HR-HPV screening. In addition, p16 INK4a immunostaining could be used as an ancillary tool to cervical cytological diagnosis, and improves its accuracy in cervical cancer screening.

Objective:To investigate the use of p16 INK4a immuno-stained cytology as the primary screening for cervical cancer prevention. Methods:From March to August 2018, 902 women from Shenzhen and surrounding area were recruited for cervical cancer screening with ThinPrep Cytologic Test (TCT), cobas4800 HPV test, and p16 INK4a co-test. Colpo/biopsies were performed using the point of interest biopsy protocol of directed and random cervical biopsies plus endocervical curettage for all women, any of whose tests was positive. Two senior cytopathologists interpreted TCT and p16 INK4a test. The performance of p16 INK4a for early detection of CIN2+ and inter-observer reproducibility of the interpretation of p16 INK4a were evaluated. Results:The positive rates of HPV test, p16 INK4a co-test and TCT diagnosed as LSIL/AGC or higher grade were 8.1% (73/902), 6.8% (61/902) and 4.7% (42/902), respectively. Colposcopy referring rate was 79.6% (109/137), among which 10 cases were diagnosed as CIN2+ (5 cases of CIN2 and 5 cases of CIN3). The sensitivity and specificity for CIN2+ of p16 INK4a test, TCT (LSIL/AGC or higher grade) and HPV test were 90.0%, 80.0%, 100.0% and 90.9%, 91.9%, 82.5%, respectively. Compared to TCT and HPV test, there was no significant difference in sensitivity and specificity between p16 INK4a and TCT/HPV test ( P>0.05). The Kappa value of the 2 cytopathologists in interpreting p16 INK4a and TCT was 0.944 and 0.425, respectively ( P<0.05). Conclusions:p16 INK4a for cervical cancer screening is equally sensitive to HPV test and specific to TCT while subjective difference of cytopathologists′ interpretation of p16 INK4a is small. Therefore, p16 INK4a can be used as a new cervical cancer screen method for its better diagnostic performance.