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Early ketamine exposure results in cardiac enlargement and heart dysfunction in Xenopus embryos.

Guo R, Liu G, Du M, Shi Y, Jiang P, Liu X, Liu L, Liu J, Xu Y - BMC Anesthesiol (2016)

Bottom Line: However, with the exception of studies about the nervous system, studies about the effect of early ketamine exposure on embryos are rare.Moreover, the heart rate and ventricular shortening fraction were decreased, findings indicative of heart dysfunction.The heart enlargement and decreased VSF may result from the down-regulation of XMLC2 mRNA and protein levels.

View Article: PubMed Central - PubMed

Affiliation: Department of Anesthesiology, Children's Hospital of Chongqing Medical University, Ministry of Education Key Laboratory of Child Development and Disorders, Key Laboratory of Pediatrics in Chongqing, Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, Chongqing, 400014, PR China.

ABSTRACT

Background: Ketamine is a commonly used clinical anesthetic and a popular recreational drug. However, with the exception of studies about the nervous system, studies about the effect of early ketamine exposure on embryos are rare. Xenopus laevis is a commonly used vertebrate model for assessing teratogenicity. Therefore, we treated Xenopus embryos with ketamine to evaluate its teratogenicity on embryos.

Methods: Xenopus embryos were treated with ketamine from stages 8 to 21. Embryonic and cardiac morphology were analyzed using living embryo imaging and whole-mount RNA in situ hybridization (WMISH). Heart function was measured by heart rate and ventricular shortening fraction (VSF). The mRNA expression levels of several heart development-related genes were determined by reverse transcription quantitative polymerase chain reaction (RT-qPCR). The protein expression levels of XMLC2, phospho-histone H3 (pH3) and histone H3 were determined by western blot.

Results: Ketamine caused concentration-dependent increases in mortality and shortening of body length. At a dose of 0.5 mg/ml, ketamine exposure resulted in cardiac enlargement as the primary manifestation of several malformations: gut defects, a curved axis and shortened body length. Cardiac cells underwent increased proliferation. Moreover, the heart rate and ventricular shortening fraction were decreased, findings indicative of heart dysfunction. XMLC2 expression levels were down-regulated at stages 28, 32/33, 35/36 and 46.

Conclusions: Ketamine exposure during early development has teratogenic effects on Xenopus embryos. The heart enlargement and decreased VSF may result from the down-regulation of XMLC2 mRNA and protein levels. These findings provide new insight into the potential fetal defects induced by ketamine exposure during early pregnancy.

No MeSH data available.


Related in: MedlinePlus

The effect of ketamine on heart development-related gene expression. a The mRNA levels of heart-specific genes XNkx2.5 and XTnIc in whole embryos, carcasses and dissected tissues at stage 46. *P < 0.05, #P < 0.05. b The mRNA levels of heart development-related genes, XNkx2.5, XTnIc, MHC-alpha, gata4, gata6b and XMLC2 in dissected tissues at stage 46. *P < 0.05. c XMLC2 mRNA levels at stage 28, 32/33 and 35/36. d XMLC2 protein levels at stage 28, 32/33, 35/36 and 46. e Quantitation of the levels of XMLC2 protein shown in D. The data are expressed as the means ± SD. Con control, K ketamine, st stage
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Fig5: The effect of ketamine on heart development-related gene expression. a The mRNA levels of heart-specific genes XNkx2.5 and XTnIc in whole embryos, carcasses and dissected tissues at stage 46. *P < 0.05, #P < 0.05. b The mRNA levels of heart development-related genes, XNkx2.5, XTnIc, MHC-alpha, gata4, gata6b and XMLC2 in dissected tissues at stage 46. *P < 0.05. c XMLC2 mRNA levels at stage 28, 32/33 and 35/36. d XMLC2 protein levels at stage 28, 32/33, 35/36 and 46. e Quantitation of the levels of XMLC2 protein shown in D. The data are expressed as the means ± SD. Con control, K ketamine, st stage

Mentions: We firstly anesthetized the embryos at stage 46 and dissected out the heart regions under a microscope. The dissected tissues were subsequently used to detect the mRNA expression levels of several heart development-related genes using RT-qPCR. In the dissected tissues, the expression levels of XNkx2.5 and XTnIc were significantly higher than that in the whole embryos and the remaining carcasses (P < 0.05) (Fig. 5a), confirming that the dissected tissues were hearts. Then, we examined the mRNA expression levels of XNkx2.5, XTnIc, MHC-alpha, gata4, gata6b and XMLC2 in these tissues (Fig. 5b). The data indicated that only XMLC2 mRNA was decreased in the ketamine-treated group (P < 0.05), whereas the other gene expression levels showed no significant difference in the two groups. Furthermore, we examined XMLC2 mRNA expression during three early stages of heart development (Fig. 5c). The expression levels were all significantly decreased in the ketamine-treated group (P < 0.05), which were consistent with the results observed at stage 46. We then detected XMLC2 protein expression using western blot at four stages. The result demonstrated that the expression levels were all down-regulated in the ketamine-treated groups (Fig. 5d-e).Fig. 5


Early ketamine exposure results in cardiac enlargement and heart dysfunction in Xenopus embryos.

Guo R, Liu G, Du M, Shi Y, Jiang P, Liu X, Liu L, Liu J, Xu Y - BMC Anesthesiol (2016)

The effect of ketamine on heart development-related gene expression. a The mRNA levels of heart-specific genes XNkx2.5 and XTnIc in whole embryos, carcasses and dissected tissues at stage 46. *P < 0.05, #P < 0.05. b The mRNA levels of heart development-related genes, XNkx2.5, XTnIc, MHC-alpha, gata4, gata6b and XMLC2 in dissected tissues at stage 46. *P < 0.05. c XMLC2 mRNA levels at stage 28, 32/33 and 35/36. d XMLC2 protein levels at stage 28, 32/33, 35/36 and 46. e Quantitation of the levels of XMLC2 protein shown in D. The data are expressed as the means ± SD. Con control, K ketamine, st stage
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4836076&req=5

Fig5: The effect of ketamine on heart development-related gene expression. a The mRNA levels of heart-specific genes XNkx2.5 and XTnIc in whole embryos, carcasses and dissected tissues at stage 46. *P < 0.05, #P < 0.05. b The mRNA levels of heart development-related genes, XNkx2.5, XTnIc, MHC-alpha, gata4, gata6b and XMLC2 in dissected tissues at stage 46. *P < 0.05. c XMLC2 mRNA levels at stage 28, 32/33 and 35/36. d XMLC2 protein levels at stage 28, 32/33, 35/36 and 46. e Quantitation of the levels of XMLC2 protein shown in D. The data are expressed as the means ± SD. Con control, K ketamine, st stage
Mentions: We firstly anesthetized the embryos at stage 46 and dissected out the heart regions under a microscope. The dissected tissues were subsequently used to detect the mRNA expression levels of several heart development-related genes using RT-qPCR. In the dissected tissues, the expression levels of XNkx2.5 and XTnIc were significantly higher than that in the whole embryos and the remaining carcasses (P < 0.05) (Fig. 5a), confirming that the dissected tissues were hearts. Then, we examined the mRNA expression levels of XNkx2.5, XTnIc, MHC-alpha, gata4, gata6b and XMLC2 in these tissues (Fig. 5b). The data indicated that only XMLC2 mRNA was decreased in the ketamine-treated group (P < 0.05), whereas the other gene expression levels showed no significant difference in the two groups. Furthermore, we examined XMLC2 mRNA expression during three early stages of heart development (Fig. 5c). The expression levels were all significantly decreased in the ketamine-treated group (P < 0.05), which were consistent with the results observed at stage 46. We then detected XMLC2 protein expression using western blot at four stages. The result demonstrated that the expression levels were all down-regulated in the ketamine-treated groups (Fig. 5d-e).Fig. 5

Bottom Line: However, with the exception of studies about the nervous system, studies about the effect of early ketamine exposure on embryos are rare.Moreover, the heart rate and ventricular shortening fraction were decreased, findings indicative of heart dysfunction.The heart enlargement and decreased VSF may result from the down-regulation of XMLC2 mRNA and protein levels.

View Article: PubMed Central - PubMed

Affiliation: Department of Anesthesiology, Children's Hospital of Chongqing Medical University, Ministry of Education Key Laboratory of Child Development and Disorders, Key Laboratory of Pediatrics in Chongqing, Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, Chongqing, 400014, PR China.

ABSTRACT

Background: Ketamine is a commonly used clinical anesthetic and a popular recreational drug. However, with the exception of studies about the nervous system, studies about the effect of early ketamine exposure on embryos are rare. Xenopus laevis is a commonly used vertebrate model for assessing teratogenicity. Therefore, we treated Xenopus embryos with ketamine to evaluate its teratogenicity on embryos.

Methods: Xenopus embryos were treated with ketamine from stages 8 to 21. Embryonic and cardiac morphology were analyzed using living embryo imaging and whole-mount RNA in situ hybridization (WMISH). Heart function was measured by heart rate and ventricular shortening fraction (VSF). The mRNA expression levels of several heart development-related genes were determined by reverse transcription quantitative polymerase chain reaction (RT-qPCR). The protein expression levels of XMLC2, phospho-histone H3 (pH3) and histone H3 were determined by western blot.

Results: Ketamine caused concentration-dependent increases in mortality and shortening of body length. At a dose of 0.5 mg/ml, ketamine exposure resulted in cardiac enlargement as the primary manifestation of several malformations: gut defects, a curved axis and shortened body length. Cardiac cells underwent increased proliferation. Moreover, the heart rate and ventricular shortening fraction were decreased, findings indicative of heart dysfunction. XMLC2 expression levels were down-regulated at stages 28, 32/33, 35/36 and 46.

Conclusions: Ketamine exposure during early development has teratogenic effects on Xenopus embryos. The heart enlargement and decreased VSF may result from the down-regulation of XMLC2 mRNA and protein levels. These findings provide new insight into the potential fetal defects induced by ketamine exposure during early pregnancy.

No MeSH data available.


Related in: MedlinePlus