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Xiao-qing Zhao

Publications and source records attributed to Xiao-qing Zhao.

5 recordsLinked to original sources
PubMed2005

[Abnormal development of conotruncal region in Cx43 knockout mice].

OBJECTIVE: To explore the etiology of the conotruncal malformations in Cx43 knockout mice. METHODS: The objects were C57/BL6 mice of E11.5 to 1 day after birth by the mating of 2 month old heterozygous mice which included Cx43 (knockout, KO) homozygotes (Cx43-/-), heterozygotes (Cx43+/-) and wild-types (Cx43+/+) genotyped by PCR method. Microdissection and HE staining were used to examine the structures of hearts. The expression of the alpha-SCA, alpha-SMA, AP-2alpha were detected by immunohistochemistry. AP-2alpha mRNA was detected by in situ hybridization. RESULTS: Cx43-/- mice died within 24 h after birth with a swelling and blockage of the conotruncal region, which led to the obstruction of OFT and enlargement of right ventricle. HE staining showed plenty of abnormal tissues in this region forming many pouches. No apparent malformations were observed in Cx43+/- and Cx43+/+ mice. The expression of alpha-SCA in the proximal OFT septum was delayed obviously in Cx43-/- predominantly at E13.5 and E14.5. The expression of alpha-SMA in the OFT in Cx43+/- and Cx43-/- was stronger than that of Cx43+/+ mice, and mostly located in the hyperplastic conotruncal region especially at E13.5-E15.5 in Cx43-/- mice. The expression could still be observed at the birth day in Cx43-/- mice, which was not observed in Cx43+/+ mice. The expression of AP-2alpha and AP-2alpha mRNA at E13.5 increased in Cx43-/- and abnormally located in the proximal OFT septum. CONCLUSION: Cx43 KO mice are characterized by hyperplasia in conotruncal region. Cx43 KO mice exhibited a delayed myocardialization and the developmental immaturity of cardiomyocytes. The abnormal distribution of cardiac neural crest cells is likely to contribute to the conotruncal malformations in Cx43-deficient mice.

Animals↗
PubMed2005

Mutations of connexin43 in fetuses with congenital heart malformations.

BACKGROUND: Gap junction channels formed by connexin43 (Cx43) protein are important in cardiac morphogenesis, and Cx43 gene is thought to be associated with congenital heart malformation (CHM). This study was undertaken to detect the mutations of Cx43 in fetuses with CHM. METHODS: Cx43 extron DNA was amplified by PCR from 16 fetuses with a variety of CHM. The PCR products were analyzed by SSCP and DNA sequencing. Thirty children who had no CHM were selected as controls. RESULTS: Eight homozygous mutations of Cx43 were observed in a fetus with double outlet right ventricule (DORV), five of the 8 mutations were missense mutations including Arg239Trp, Ser251Thr, Ala253Pro, Pro283Leu and Thr290Asn, and the remaining 3 were silent polymorphisms including Gly252Gly, Pro256Pro and Thr275Thr. No mutations were found in other fetuses and the control group. CONCLUSIONS: Mutations of Cx43 may be associated with congenital conotruncal anomalies. PCR-SSCP is an effective method for screening the mutations of Cx43.

Connexin 43↗
PubMed2005

[Histopathological analysis of neonatal mouse hearts with connexin43 gene defects].

OBJECTIVE: To investigate the characteristics of heart morphology in neonatal mice with connexin43 gene defects. METHODS: Two mouse lines were used in this study, which included connexin43 knockout (Cx43KO) mice and CMV43(CT) transgenic mice. PCR analysis was carried out to identify the genotypes of two transgenic mice. Sections with HE staining were analyzed to display the morphologic structures of the hearts in neonatal mice. C57BL6/SJ mice were used as control. RESULTS: All 11 homozygous Cx43KO mice died within 24 hr after birth showing severe right ventricular outflow tract obstruction (RVOTO). Out of 20 homozygous CMV43(CT) transgenic mice, 12 mice died within 48 hr after birth showing not only RVOTO, but also atrial septal defect (ASD), ventricular septal defect (VSD) and other cardiac defects, while the remaining 8 mice were alive without heart defects. Both heterozygous Cx43KO and CMV43(CT) transgenic mice had normal hearts. CONCLUSION: Connexin43 gene defect is obviously associated with abnormal heart morphogenesis. The different types and different dosage of the gene defects may lead to different phenotypes of hearts.

Animals↗