Loss of SHROOM3 affects neuroepithelial cell shape through regulating cytoskeleton proteins in cynomolgus monkey organoids

Neural tube defects(NTDs)are severe congenital neurodevelopmental disorders arising from incomplete neural tube closure.Although folate supplementation has been shown to mitigate the incidence of NTDs,some cases,often attributable to genetic factors,remain unpreventable.The SHROOM3 gene has been implicated in NTD cases that are unresponsive to folate supplementation;at present,however,the underlying mechanism remains unclear.Neural tube morphogenesis is a complex process involving the folding of the planar epithelium of the neural plate.To determine the role of SHROOM3 in early developmental morphogenesis,we established a neuroepithelial organoid culture system derived from cynomolgus monkeys to closely mimic the in vivo neural plate phase.Loss of SHROOM3 resulted in shorter neuroepithelial cells and smaller nuclei.These morphological changes were attributed to the insufficient recruitment of cytoskeletal proteins,namely fibrous actin(F-actin),myosin II,and phospho-myosin light chain(PMLC),to the apical side of the neuroepithelial cells.Notably,these defects were not rescued by folate supplementation.RNA sequencing revealed that differentially expressed genes were enriched in biological processes associated with cellular and organ morphogenesis.In summary,we established an authentic in vitro system to study NTDs and identified a novel mechanism for NTDs that are unresponsive to folate supplementation.

Neurological Disorders Caused by Structural Dysfunction of VANGL2

Background: VANGL2 plays a variety of roles in various cellular processes, including tissue morphogenesis, asymmetric cell division, and nervous system development. There is currently a lack of systematic organization in the development and disease of the nervous system. Purpose: To explore the role of VANGL2 in the development of the nervous system and related diseases. Methods: Literature review and analysis of the role of VANGL2 in the development and disease of the nervous system. Results: VANGL2 defects lead to the development of the nervous system through the misconfiguration of various cells, which affects the development of the cochlea, the conduction of neural signals, and the development of nervous system-related diseases such as Alzheimer’s disease, GBM, Bohling-Opitz syndrome, and hydrocephalus. Conclusions: The VANGL2 gene is essential for nervous system development and its deficiency is linked to severe congenital conditions and various disorders, highlighting the need for more research on treatments for related gene defects.

Effect of Exposure to Trace Elements in the Soil on the Prevalence of Neural Tube Defects in a High-Risk Area of China

Objective Our objective is to build a model that explains the association between the exposure to trace elements in the soil and the risk of neural tube defects. Methods We built a function with different parameters to describe the effects of trace elements on neural tube defects. The association between neural tube defects and trace element levels was transformed into an optimization problem using the maximum likelihood method. Results Tin, lead, nickel, iron, copper, and aluminum had typical layered effects （dosage effects） on the prevalence of neural tube defects. Arsenic, selenium, zinc, strontium, and vanadium had no effect, and molybdenum had one threshold value that affected the prevalence of birth defects. Conclusion As an exploratory research work, our model can be used to determine the direction of the effect of the trace element content of cultivated soil on the risk of neural tube defects, which shows the clues by the dosage effect of their toxicological characteristics. Based on our findings, future biogeochemical research should focus on the direct effects of trace elements on human health.

Unusual Patterns of Neural Tube Defects in a High Risk Region of Northern China

Objective To study the prevalence of different types of neural tube defects （NTDs） in Luliang Prefecture, Shanxi province, where the prevalence of NTDs is unusually high and the correlation between NTDs prevalence and patterns. Methods A surveillance population-based birth defects was performed in Luliang Prefecture, Shanxi province. Results The results of our study showed that the prevalence of NTDs was 2-fold higher in Luliang Prefecture than in other areas of Shanxi province. Unusual patterns of NTDs were found, however, multiple NTDs were relatively common in Luliang Prefecture, accounting for over 13% of all NTDs cases in China. Conclusion The prevalence of NTDs is associated with its patterns.

Advanced glycation end products induce neural tube defects through elevating oxidative stress in mice

Our previous study showed an association between advanced glycation end products （AGEs） and neural tube defects （NTDs）. To understand the molecular mechanisms underlying the effect of AGEs on neural tube development, C57BL/6 female mice were fed for 4 weeks with com- mercial food containing 3% advanced glycation end product bovine serum albumin （AGE-BSA） or 3% bovine serum albumin （BSA） as a control. After mating mice, oxidative stress markers including malondialdehyde and H202 were measured at embryonic day 7.5 （E7.5） of ges- tation, and the level of intracellular reactive oxygen species （ROS） in embryonic cells was determined at E8.5. In addition to evaluating NTDs, an enzyme-linked immunosorbent assay was used to determine the effect of embryonic protein administration on the N-（carboxymethyl） lysine reactivity of acid and carboxyethyl lysine antibodies at E10.5. The results showed a remarkable increase in the incidence of NTDs at El0.5 in embryos of mice fed with AGE-BSA （no hyperglycemia） compared with control mice. Moreover, embryonic protein administration resulted in a noticeable increase in the reactivity of N-（carboxymethyl） lysine and N（ε）-（carboxyethyl） lysine antibodies. Malondialdehyde and H2O2 levels in embryonic cells were increased at E7.5, followed by increased intracellular ROS levels at E8.5. Vitamin E supplementation could partially recover these phenomena. Collectively, these results suggest that AGE-BSA could induce NTDs in the absence of hyperglycemia by an underlying mechanism that is at least partially associated with its capacity to increase embryonic oxidative stress levels.

Cell cycle-related genes p57kip2, Cdk5 and Spin in the pathogenesis of neural tube defects

In the field of developmental neurobiology, accurate and ordered regulation of the cell cycle and apoptosis are crucial factors contributing to the normal formation of the neural tube. Preliminary studies identified several genes involved in the development of neural tube defects. In this study, we established a model of developmental neural tube defects by administration of retinoic acid to pregnant rats. Gene chip hybridization analysis showed that genes related to the cell cycle and apoptosis, signal transduction, transcription and translation regulation, energy and metabolism, heat shock, and matrix and cytoskeletal proteins were all involved in the formation of developmental neural tube defects. Among these, cell cycle-related genes were predominant. Retinoic acid treat-ment caused differential expression of three cell cycle-related genes p57kip2, Cdk5 and Spin, the expression levels of which were downregulated by retinoic acid and upregulated during normal neural tube formation. The results of this study indicate that cell cycle-related genes play an im-portant role in the formation of neural tube defects. P57kip2, Cdk5 and Spin may be critical genes in the pathogenesis of neural tube defects.

Bayesian mapping of neural tube defects prevalence in Heshun County, Shanxi Province, China during 1998～2001

Objective: To estimate the prevalence rates of neural tube defects (NTDs) in Heshun County, Shanxi Province, China by Bayesian smoothing technique. Methods: A total of 80 infants in the study area who were diagnosed with NTDs were analyzed. Two mapping techniques were then used. Firstly, the GIS software ArcGIS was used to map the crude prevalence rates. Secondly, the data were smoothed by the method of empirical Bayes estimation. Results: The classical statistical approach produced an extremely dishomogeneous map, while the Bayesian map was much smoother and more interpretable. The maps produced by the Bayesian technique indicate the tendency of villages in the southeastern region to produce higher prevalence or risk values. Conclusions: The Bayesian smoothing technique addresses the issue of heterogeneity in the population at risk and it is therefore recommended for use in explorative mapping of birth defects. This approach provides procedures to identify spatial health risk levels and assists in generating hypothesis that will be investigated in further detail.

Methylmalonic Acid in Amniotic Fluid and Maternal Urine as a Marker for Neural Tube Defects

To evaluate the implication of methymalonic acid (MMA) in the early diagnosis of neural tube defects (NTD), a quantitative assay for MMA was established by using gas chromatography-mass spectrometry with stable isotope of MMA as an internal standard. Amniotic fluid and maternal urine MMA concentration, maternal serum folate, red blood cell folate and vitamin B 12 levels were measured in the middle term of NTD-affected and normal pregnancies. Amniotic fluid and maternal urine MMA concentrations in the middle term of NTD affected pregnancies (1.4±0.9 μmol/L, and 22.1±12.6 nmol/μmol creatinine) were significantly higher than that of normal pregnancies (1.0±0.4μmol/L, and 2.5±1.1 nmol/μmol creatinine). There was no significant difference between normal and NTD pregnancies for serum folate, red blood cell folate and vitamin B 12 levels. The results suggested that MMAs in amniotic fluid and maternal urine are sensitive markers for early diagnosis of NTD. Vitamin B 12 is an active cofactor involved in the remethylation of homocycteine and its deficiency is an independent risk factor for NTD. MMA is a specific and sensitive marker for intracellular vitamin B 12 deficiency. This study suggests that it is necessary to monitor the vitamin B 12 deficiency and advocates vitamin B 12 supplementation with folate prevention program.

An epidemiologic study of mitochondrial membrane transporter protein gene polymorphism and risk factors for neural tube defects in Shanxi, China

The present study involved a questionnaire survey of 156 mothers that gave birth to children with neural tube defects or had a history of pregnancy resulting in children with neural tube defects （case group） and 156 control mothers with concurrent healthy children （control group） as well as detection of mitochondrial membrane transporter protein gene [uncoupling protein 2 （UCP2）] polymorphism. The maternal UCP2 3＇ untranslated region （UTR） D/D genotype and D allele frequency were significantly higher in the case group compared with the control group （odds ratio （OR） 3.233; 95% confidence interval （C/） 1.103 9.476; P= 0.040; OR： 3.484; 95% CI： for neural tube defects 2.109 5.753; P 〈 0.001）. Univariate and multivariate logistic regression analysis of risk factors for neural tube defects showed that a matemal UCP2 3＇ UTR D/D genotype was negatively interacted with the mothers＇ consumption of frequent fresh fruit and vegetables （S = 0.007）, positively interacted with the mothers＇ frequency of germinated potato consumption （S = 2.15） and positively interacted with the mothers＇ body mass index （S = 3.50）. These findings suggest that maternal UCP2 3＇ UTR gene polymorphism, pregnancy time, consumption of germinated potatoes and body mass index are associated with an increased risk for neural tube defects in children from mothers living in Shanxi province, China. Moreover, there is an apparent gene-environment interaction involved in the development of neural tube defects in offspring.

Application of GIS-Based Spatial Filtering Method for Neural Tube Defects Disease Mapping

This study is to assess the prevalence rates spatial pattern of neural tube defects with geographic information system and spatial filtering technique. A total of 80 infants who diagnosed from neural tube defects in the area being studied between 1998 and 2001 were analyzed. Firstly, the geographic information system （GIS） software ArcGIS was used to map the crude prevalence rates. Secondly, the data were smoothed by the method of spatial filtering. We evaluated that the effect of changes in spatial filtering radius size was assessed by creating maps based on various filtering radius sizes. The 3 miles or larger filtering radius gives better section variability than the 2 and 2.5 miles or smaller ones. The maps produced by the spatial filtering technique indicate that prevalence rates in the villages in the southeastern region are to produce higher prevalence than that in the other regions. The smoothed maps based on Heshun County display a more adequate data representation than the raw prevalence rate map.

Polymorphisms of the maternal Slug gene in fetal neural tube defects in a Chinese population

Several studies have demonstrated that Slug,which encodes a zinc finger of the Snail family of transcription factors,is a potential risk factor for neural tube defects.Neural tube defects tend to occur with a high rate in Shanxi province,China.The present case-control study investigated genotypic distributions and allele frequencies of Slug C1548A polymorphisms in DNA samples from59 women with a history of neural tube defect pregnancies and 73 controls during the same period from Shanxi Province,China.Results demonstrated that women with a history of neural tube defect pregnancies had significantly greater genotypic distributions of Slug AA genotypes and A allele frequencies compared with controls,and A allele Slug C1548A was a risk factor for neural tube defects（odds ratio = 3.444;95% confidence interval;2.021-5.868,P 〈 0.05）.Three-dimensional structure prediction revealed that Slug C1548A resulted in transition of aspartic acid into glutamate at position 119.This indicated that these mutations could lead to damaged protein structure and function.These findings suggest that Slug C1548A gene polymorphism is closely related to neural tube defects in a population of Han Chinese origin from Shanxi Province,China

Retinoic acid induction of genes associated with neural tube developmental defects

To date, little information has been available regarding genes involved in the regulation of embryonic cell development, which participate in retinoic acid-induced neural tube defects in mice. Previous studies have revealed seven differentially expressed genes involved in neural tube developmental defects. However, gene expression and regulation is a complex process. Therefore, gene expression differences between normal and defective neural tubes at 9.5 and 10.5 days were compared. A total of eight differentially expressed genes exhibited coincident alterations at embryonic 9.5 and 10.5 days. In mice with retinoic acid-induced neural tube defects, NeK7, IGFBP5 ZW10, Csf3r, PSMC6, Cdk5, and Rbl expressions were downregulated, but Apoa-4 expression was upregulated. These results were confirmed by Northern blot hybridization. Results suggested that NeK7, IGFBP5, ZW10, Csf3r, PSMC6, Cdk5, Rb1, and Apoa-4 are important regulatory factors involved in neural tube defects.

Gene expression in retinoic acid-induced neural tube defects A cDNA microarray analysis

BACKGROUND： Neural tube defects can be induced by abnormal factors in vivo or in vitro during development. However, the molecular mechanisms of neural tube defect induction, and the related gene expression and regulation are still unknown. OBJECTIVE： To compare the differences in gene expression between normal embryos and those with neural tube defects. DESIGN, TIME AND SETTING： A neural development study was performed at the Department of Neurobiology, Third Military Medical University of Chinese PLA between January 2006 and October 2007. MATERIALS： Among 120 adult Kunming mice, 60 pregnant mice were randomly and evenly divided into a retinoic acid group （n = 30） and a normal control group （n =30）. The retinoic acid was produced by Sigma, USA, the gene microarray by the Amersham Pharmacia Company, Hong Kong, and the gene sequence was provided by the Incyte database, USA. METHODS： Retinoic acid was administered to prepare models of neural tube defects, and corn oil was similarly administered to the normal control group. Total RNA was extracted from embryonic tissue of the two groups using a Trizol kit, and a cDNA microarray containing 1 100 known genes was used to compare differences in gene expression between the normal control group and the retinoic acid group on embryonic （E） day 10.5 and 11.5. Several differentially expressed genes were randomly selected from the two groups for Northern blotting, to verify the results of the cDNA microarray. MAIN OUTCOME MEASURES： Morphological changes and differential gene expression between the normal control group and the retinoic acid group. RESULTS： Anatomical microscopy demonstrated that an intact closure of the brain was formed in the normal mouse embryos by days E10.5 and E11.5. The cerebral appearance was full and smooth, and the surface of the spine was intact. However, in the retinoic acid group on days E10.5 and E11.5, there were more dead embryos. Morphological malformations typically included non-closure at the top of the cranium and abnormal changes of the metencephalon and face. cDNA microarray analysis suggested that the changes in expression of seven different genes were similar on both days E10.5 and E11.5. These were downregulation of NekT, Igfbp5, Zw10, Csf3r, Psmc6 and Rb 1, and upregulation of Apoa-4. This study also indicated that Cdk5 expression was downregulated in the retinoic acid group on day E11.5. The results of the cDNA microarray analysis were partly confirmed by Northern blotting. CONCLUSION： Cdk5, Nek7, Igfbp5, Zw10, Csf3r, Psmc6, Rb1 and Apoa-4 may be key factors in retinoic acid-induced neural tube defects.

PSO/ACO Algorithm-based Risk Assessment of Human Neural Tube Defects in Heshun County,China

Abstract Objective To develop a new technique for assessing the risk of birth defects, which are a major cause of infant mortality and disability in many parts of the world. Methods The region of interest in this study was Heshun County, the county in China with the highest rate of neural tube defects （NTDs）. A hybrid particle swarm optimization/ant colony optimization （PSO/ACO） algorithm was used to quantify the probability of NTDs occurring at villages with no births. The hybrid PSO/ACO algorithm is a form of artificial intelligence adapted for hierarchical classification. It is a powerful technique for modeling complex problems involving impacts of causes. Results The algorithm was easy to apply, with the accuracy of the results being 69.5%＋7.02% at the 95% confidence level. Conclusion The proposed method is simple to apply, has acceptable fault tolerance, and greatly enhances the accuracy of calculations.

Study of A1298C MTHFR Gene Polymorphism as a Risk Factor for Neural Tube Defects in the Eastern Algerian Population

Background: As C677T mutation, A1298C mutation in methylene tetrahydrofolate reductase (MTHFR) gene results in a decreased MTHFR activity but to a less extent, it is known as a risk factor of predisposition to human neural tube defects (NTDs), in some populations. Our objective was therefore to study, for the first time in Algerian population, if A1298C polymorphism confers risk for the occurrence of this abnormality. We have examined the distribution of the genotype and the allele frequencies of A1298C mutation, and also their influence on plasma homocysteine (Hcy) concentration. Patients and Methods: We studied this polymorphism in 38 mothers of NTD cases and 67 control individuals of an eastern Algerian population. The mutation was determined by polymerase chain reaction-restriction fragment length polymorphism analysis (PCR/RFLP). Plasma homocysteine concentration was analyzed using an automated chemiluminescence method. Results: No signi?cant association could be observed between allele and genotypes frequencies of A1298C MTHFR gene polymorphism and NTDs risk. However, we could observe that A1298C polymorphism affects homocysteine metabolism in mothers of NTD cases leading to homocysteine concentration values higher in AA genotype and lower in AC/CC genotypes (15.29 ± 11.8 μmol/l vs. 8.63 ± 3.83 μmol/l, p < 0.05). Conclusion: Data indicate that A1298C MTHFR gene polymorphism might be a risk factor by affecting homocysteine metabolism in mothers of Algerian children with NTDs.

An Overview of Spina Bifida

A child born with untreatable birth defect encounters constant challenges in lifetime. Spina bifida is such type of defect mainly affecting neural tube. As a result, a child with spina bifida faces abnormal physical appearance to neurological dysfunctions. The incident rate of such birth defect is relatively common compared to other birth defects, therefore, an awareness among people is necessary to avoid such vulnerability. Therefore, this article provides a general outline of symptoms, types, risk factors, pathophysiology, preventive and therapeutic strategies of spina bifida which will help the general people for better understanding of the disease and be able to take precautions to combat such defect.

Physical Blocking Neural Tube Closure Affects Radial Intercalation and Neural Crest Midline-directed Migration in Xenopus Dorsal Explants

Neural tube defects （NTDs） are severe congenital malformation diseases, which occur in 1 out of 1000 births in human. In Xenopus, several tissue movements are involved in the neural tube closure process. Immediately after the neural tube fusion, the neural crest cells get monopolar protrusion toward dorsal midline and migrate to form the roof of the neural tube. At the same time, radial intercalation takes place from the ventral neural tube and forces it to be single-layered. Here, we physically block the neural tube closure to test the cell movements and the following patterning in Xenopus laevis explants. The results show that the single-layered neural tube fails to form and the neural crest cells remain at the lateral regions in the explants with NTDs. However, the patterning of the neural tube is not affected as indicated by the normal expression of the preneural genes. These results indicate a requirement of the neural tube fusion for the radial intercalation and the dorsal midline directed neural crest migration, but not for the dorsal-ventral patterning of the neural tube.

Brain stem global gene expression profiles in human spina bifida embryos

Environmental and genetic factors influence the occurrence of neural tube defects, such as spina bifida. Specific disease expression patterns will help to elucidate the pathogenesis of disease. However, results obtained from animal models, which often exhibit organism specificity, do not fully explain the mechanisms of human spina bifida onset. In the present study, three embryos with a gestational age of approximately 17 weeks and a confirmed diagnosis of spina bifida, as well as 3 age-matched normal embryos, were obtained from abortions. Fetal brain stem tissues were dissected for RNA isolation, and microarray analyses were conducted to examine profiles of gene expression in brain stems of spina bifida and normal embryos using Affymetrix HG-U133A 2.0 GeneChip arrays. Of the 14 500 gene transcripts examined, a total of 182 genes exhibited at least 2.5-fold change in expression, including 140 upregulated and 42 downregulated genes. These genes were placed into 19 main functional categories according to the Gene Ontology Consortium database for biological functions. Of the 182 altered genes, approximately 50% were involved in cellular apoptosis, growth, adhesion, cell cycle, stress, DNA replication and repair, signal transduction, nervous system development, oxidoreduction, immune responses, and regulation of gene transcription. Gene expression in multiple biological pathways was altered in the brain stem of human spina bifida embryos.

Ultrastructural changes in embryoic neuroepithelial cells caused by passive smoking in golden hamsters at different periods of pregnancy: A randomized controlled trial

BACKGROUND： Tobacco smoke exposure is recognized as a health risk for pregnant women and it is increasingly evident that tobacco smoke affects the development of brain. Recently, associations between maternal smoking during pregnancy and subsequent mental health problems in offspring have been reported. OBJECTIVE： To observe the effect of passive smoking on the morphology of nerve tissues and the ultrastructure of neuroepithelial cells during embryogenesis in golden hamster at different pregnant period. DESIGN： A randomized control study. SETTING： Department of Histology and embryology, Qingdao University. MATERIALS： Adult golden hamsters, including 40 males and 40 females that had not delivered, weighing （105±5） g, were provided by Shenyang Changsheng Biotechnology, Co.,Ltd. At 20 ： 00 - 21 ： 00, one male and one female were matched in each cage, and their mating was observed. The vaginal swabs were examined the next day and the day of positive sperm was taken as embryonic day 1 （E1）. METHODS： The experiment was completed in the Department of Histology and Embryology of Qingdao University from September 2001 to September 2003. （1） Abnormality caused by smoking, grouping and model establishment： A total of 40 healthy pregnant golden hamsters were randomly divided into control group （n =20） and experimental group （n =20）. The hamsters in the experimental group were exposed to tobacco smoke from embryonic day 4 to 7, 3 times per day, continuously 1 hour per time, 1 cigarette per golden hamster, for 4 consecutive days in the self-made chamber. The animals in the control group were given the same conditions as those in the experimental group except exposure to smoke. （2） Observation with transmission electron microscope： According to different gestational ages, the experimental group and the control group were all divided 4 subgroups （Groups A, B, C and D） respectively, and 5 hamsters in each subgroup. The pregnant golden hamsters were anaesthetized with 1 g/L pentobarbital sodium at 12 ： 00 and 18 ： 00 at E8, 8 ： 00 at E9 and 8 ： 00 at E10, and all the pregnant uteruses were divulsed under the stereomicroscope. The development of the neural plate, neural groove and neural tube were observed. Meanwhile, the amount of normal embryos and abnormal embryos including the neural tube defect ratios were recorded. （3） Electron microscopic specimen preparation and observation： Three embryos of each group ad libtium were fixed. The alternations of neuroepithelial ultrastrnctures were observed with transmission and scanning electron microscopes. MAIN OUTCOME MEASURES： （1） The incidences of abnormality of nervous system development were observed under stereomicroscope and scanning electron microscope in smoking group and the control group; （2） Alternations of neuroepithelial ultrastructures were observed with transmission electron microscope. RESULTS： All the 40 pregnant golden hamsters were involved in the final analysis. （1） Manifestations and incidence of nervous system dysplasia： Passive smoking could induce dymorphogenesis during neurnlation, which mainly presented as growth retardation, spina bifida and failure of formation of neural tubes; The incidences of the nervous system dysplasia in the experimental groups [20%（10/49）, 27%（14/51）, 32% （19/59）, 27% （17/63）] were higher than those in the corresponding control groups [0. 2% （1/57）, 4% （2/53）, 4% （2/52）, P 〈 0.01]. （2） Histomorphological changes at different time points after spermatiation observed with transmission and scanning electron microscopes： In the control group, the embryos formed C-shape columned embryos, anterior and posterior neuropores were all closure at 10 ： 00 on E10; In the experimental group, unfused anterior and posterior neuropores still could be found, and some embryos presented spina bifida at 10 ： 00 on E10. In the control group, neuroepithelial cell arranged tidily and closely, the boundary of the cells was clear, the flee surface of neuroepithelial had a mass of long and regular microvillus, and the surface of mesenchymal cell around the neuroepithelium had many processes which mutually related at 12 ： 00 on E8. In the experimental group, the neuroepithelial cells arranged irregularly and the intercellular spaces became wide at 12 ： 00 on E8. The apical portion of many neuroepithelial cells bulged into the lumen and many microvilli were shorted and swollen. The quantity of the microvillus reduced gradually, evenly disappeared with the increasing of gestational age at 18：00 on E8. Under transmission electron microscope, the neuroepithelial cells in experimental embryos arranged irregularly. There were many visible materials in the intercellular space which increased the breadth and anomaly. It was apparent that passive smoking evoked major alterations in neuroepithelial cytoarchitecture. Junctional complex reduced. Many microvilli were shorted and swollen, even the apical portion of many neuroepithelial cells bulged, and abscised into the lumen. A lot of vacuolation appeared in the cytoplasm of neuroepithelia and mesenchymal cell around the neuroepithelium. The cristae of mitochondria reduced even disappeared, and some mitochondria became elongate. Irregular nuclear, increased heterochromatin and karyopycnosis/karyorrhexis were observed easily. Perinuclear cisternae partially swelled and embraced tangible material （maybe the material from nuclear）. Some death cells separated into a lot of apoptotic bodies. Some apoptotic bodies were found in the cytoplasm of other healthy-looking or healthy cells. CONCLUSION： Passive smoking may induce degeneration, apoptosis, and cells loss in the neural epithelium, thereby result in failure of formation and differentiation of neural tube. It is an important way by which passive smoking caused neural tube defects.

Correlation between spina bifida manifesta in fetal rats and c-Jun N-terminal kinase signaling

Fetal rat models with neural tube defects were established by injection with retinoic acid at 10 days after conception. The immunofluorescence assay and western blot analysis showed that the number of caspase-3 positive cells in myeloid tissues for spina bifida manifesta was increased. There was also increased phosphorylation of c-Jun N-terminal kinase, a member of the mitogen activated protein kinase family. The c-Jun N-terminal kinase phosphorylation level was positively correlated with caspase-3 expression in myeloid tissues for spina bifida manifesta. Experimental findings indicate that abnormal apoptosis is involved in retinoic acid-induced dominant spina bifida formation in fetal rats, and may be associated with the c-Jun N-terminal kinase signal transduction pathway.