Alteration of lens and retina textures from mice embryos with folic acid deficiency: image processing analysis

Purpose: Folic acid (FA) is an essential vitamin for embryonic development. It plays particularly a critical role in RNA, DNA and protein synthesis. On the other hand, the collagen IV and laminin-1 are important proteins during embryonic development. This study was done to find if FA deficiency at a short and a long term in mothers could alter the tissue texture of retina and lens of the progeny. Methods: Collagen IV and laminin-1 were localized by immunohistochemistry in the lens and retina of the FA-deficient embryos. To carry out the image processing, texture segmentation was performed through canny edge detection and Fourier transform (FT). We defined a parameter, the grain size, to describe the texture of the lens and retina. A bootstrap method to estimate the distribution and confidence intervals of the mean, standard deviation, skewness and kurtosis of the grain size has been developed. Results: Analysis through image processing using Matlab showed changes in the grain size between control- and FA-deficient groups in both studied molecules. Measures of texture based on FT exhibited changes in the directionality and arrangements of type IV collagen and laminin-1. Conclusions: Changes introduced by FA deficiency were visible in the short term (2 weeks) and evident in the long term (8 weeks) in both grain size and orientation of fibre structures in the tissues analysed (lens and retina). This is the first work devoted to study the effect of FA deficit in the texture of eye tissues using image processing techniques

Multispectral Imaging Method for Rapid Identification and Analysis of Paraffin-Embedded Pathological Tissues

The study of the interaction between light and biological tissue is of great help in the identification of diseases as well as structural alterations in tissues. In the present study, we have developed a tissue diagnostic technique by using multispectral imaging in the visible spectrum combined with principal component analysis (PCA). We used information from the propagation of light through paraffin-embedded tissues to assess differences in the eye tissues of control mouse embryos compared to mouse embryos whose mothers were deprived of folic acid (FA), a crucial vitamin necessary for the growth and development of the fetus. After acquiring the endmembers from the multispectral images, spectral unmixing was used to identify the abundances of those endmembers in each pixel. For each acquired image, the final analysis was performed by performing a pixel-by-pixel and wavelength-by-wavelength absorbance calculation. Non-negative least squares (NNLS) were used in this research. The abundance maps obtained for the first endmember revealed vascular alterations (vitreous and choroid) in the embryos with maternal FA deficiency. However, the abundance maps obtained for the third endmember showed alterations in the texture of some tissues such as the lens and retina. Results indicated that multispectral imaging applied to paraffin-embedded tissues enhanced tissue visualization. Using this method, first, it can be seen tissue damage location and then decide what kind of biological techniques to apply

Development of a polarization imaging method to detect paraffin‐embedded pathology tissues before applying other techniques

The present article describes the development of a technique, applied to paraffin‐embedded tissues, which uses three different wavelengths of monochromatic light (λ1 = 445 nm, λ2 = 540 nm and λ3 = 660 nm) for the measures of the degree of polarization, degree of linear polarization, degree of circular polarization and birefringence, all obtained from measurements of Stokes parameters by using polarized light. The goal of this study was to detect changes in developing embryonic mouse eye when pregnant mice fed diets without folic acid for variable periods compared with a healthy control group. We present a biomedical diagnostic technique based on polarized light detection applied to paraffin‐embedded tissues to visualize the structural damage to aid us in the diagnosis before applying other techniques. Through this method, we can visualize and identify which parts of the tissue were altered with respect to the control group

Gestational folic acid deficiency alters embryonic eye development: Possible role of basement membrane proteins in eye malformations.

Objectives: Folic acid (FA) is crucial before and during early pregnancy. FA deficiency can occur because dietary FA intake is low in mothers at the time of conception. Likewise, various ocular pathologies are related to the alteration of extracellular matrices. The present study aimed to investigate the association between maternal FA deficiency and congenital eye defects. We also investigated whether maternal diet deficient in FA alters the expression of collagen IV and laminin-1 as a possible mechanism responsible for the appearance of ocular malformations. Both proteins are the main components of the basal lamina, and form an interlaced network that creates a relevant scaffold basement membrane. Basal laminae are involved in tissues maintenance and implicated in regulating many cellular processes. Methods: A total of 57 mouse embryos were classified into the following groups: Control group, (mothers were fed a standard rodent diet), and D2 and D8 groups (mothers were fed FA-deficient [FAD] diet for 2 or 8 wk, respectively). Female mice from group D2 were fed a FAD diet (0 mg/kg diet + 1% succinyl sulfathiazole used to block the synthesis of FA) for 2 wk from the day after mating until day 14.5 of gestation (E14.5). On the other hand, female mice from group D8 were fed a FAD diet for 8 wk (6 wk before conception and during the first 2 wk of pregnancy). For the data analysis, we first estimated the incidence of malformations in each group. Then, the statistical analysis was performed using IBM SPSS Statistics, version 25.0. Expression patterns of collagen IV and laminin-1 were examined with the immunohistochemical technique. Results: Our results showed that mice born to FA-deficient mothers had several congenital eye abnormalities. Embryos from dams fed a short-term FAD diet were found to have many significant abnormalities in both anterior and posterior segments, as well as choroidal vessel abnormalities. However, embryos from dams fed a long-term FAD diet had a significantly higher incidence of eye defects. Finally, maternal FA deficiency increased the expression of both collagen IV and laminin-1. Likewise, changes in the spatial localization and organization of collagen IV were observed. Conclusions: A maternal FAD diet for a short-term period causes eye developmental defects and induces overexpression of both collagen IV and laminin-1. The malformations observed are probably related to alterations in the expression of basement membrane proteins

Multifractal analysis of embryonic eye structures from female mice with dietary folic acid deficiency. Part II: Fractal dimension, lacunarity, divergence, and multifractal spectrum

The aim of this work is to study local changes of fractality in mouse embryonic lens. Embryos were removed from female mice that have been subjected to a diet deficient in folic acid for two and eight weeks. The local change of fractality is studied through the analysis of the Local Connected Fractal Dimension (LCFD) on binarised images of these lenses using FracLac plugin for ImageJ, after immunohistochemical analysis performed using anti-collagen IV or anti-laminin-1. The samples were analysed previously by the authors to locate under and overexpression lens zones of these proteins. The results show that there are variations of the LCFD with respect to control groups. These changes show significant positive correlations with changes in spatial patterns of both proteins expression

Epidermal Growth Factor Impairs Palatal Shelf Adhesion and Fusion in the T gf-β3 Null Mutant

The cleft palate presented by transforming growth factor-β3 (Tgf-β3 ) null mutant mice is caused by altered palatal shelf adhesion, cell proliferation, epithelial-to-mesenchymal transformation and cell death. The expression of epidermal growth factor (EGF), transforming growth factor-β1 ( Tgf-β1 ) and muscle segment homeobox-1 (Msx-1) is modified in the palates of these knockout mice, and the cell proliferation defect is caused by the change in EGF expression. In this study, we aimed to determine whether this change in EGF expression has any effect on the other mechanisms altered in Tgf-β 3 knockout mouse palates. We tested the effect of inhibiting EGF activity in vitro in the knockout palates via the addition of Tyrphostin AG 1478. We also investigated possible interactions between EGF, Tgf-β 1 and Msx-1 in Tgf-β 3 null mouse palate cultures. The results show that the inhibition of EGF activity in Tgf-β 3 null mouse palate cultures improves palatal shelf adhesion and fusion, with a particular effect on cell death, and restores the normal distribution pattern of Msx-1 in the palatal esenchyme. Inhibition of TGF-β 1 does not affect either EGF or Msx-1 expression

Interactions between TGF-beta1 and TGF-beta3 and their role in medial edge epithelium cell death and palatal fusion in vitro

In recent decades, studies have shown that both TGF-b1 and TGF-b3 play an important role in the induction of medial edge epithelium (MEE) cell death and palatal fusion. Many of these experiments involved the addition or blockage of one of these growth factors in wild-type (WT) mouse palate cultures, where both TGF-b1 and TGF-b3 are present. Few studies have addressed the existence of interactions between TGF-b1 and TGF-b3, which could modify their individual roles in MEE cell death during palatal fusion. We carried out several experiments to test this possibility, and to investigate how this could influence TGF-b1 and TGF-b3 actions on MEE cell death and palatal shelf fusion. We double immunolabelled developing mouse palates with anti-TGF-b1 or anti-TGF-b3 antibodies and TUNEL, added rhTGF-b1 or rhTGF-b3 or blocked the TGF-b1 and TGF-b3 action at different concentrations to WT or Tgf-b3 null mutant palate cultures, performed in situ hybridizations with Tgf-b1 or Tgf-b3 riboprobes, and measured the presence of TUNEL-positive midline epithelial seam (MES) cells and MES disappearance (palatal shelf fusion) in the different in vitro conditions. By combining all these experiments, we demonstrate great interaction between TGF-b1 and TGF-b3 in the developing palate and confirm that TGF-b3 has a more active role in MES cell death than TGF-b1, although both are major inductors of MES disappearance. Finally, the co-localization of TGF-b1, but not TGF-b3, with TUNEL in the MES allows us to suggest a possible role for TGF-b1 in MES apoptotic clearance.Ministerio de Sanidad de EspañaComunidad Autónoma de MadridUniversidad ComplutenseDepto. de Anatomía y EmbriologíaFac. de MedicinaTRUEpu

Alteration of medial-edge epithelium cell adhesion in two Tgf-beta3 null mouse strains

Although palatal shelf adhesion is a crucial event during palate development, little work has been carried out to determine which molecules are responsible for this process. Furthermore, whether altered palatal shelf adhesion causes the cleft palate presented by Tgf-b3 null mutant mice has not yet been clarified. Here, we study the presence/distribution of some extracellular matrix and cell adhesion molecules at the time of the contact of palatal shelves in both wild-type and Tgf-b3 null mutant palates of two strains of mice (C57/BL/6J(C57), and MF1) that develop cleft palates of different severity. We have performed immunohistochemistry with antibodies against collagens IV and IX, laminin, fibronectin, the a5- and b1-integrins, and ICAM-1; in situ hybridization with a Nectin-1 riboprobe; and palatal shelf cultures treated or untreated with TGF-b3 or neutralizing antibodies against fibronectin or the a5-integrin. Our results show the location of these molecules in the wild-type mouse medial edge epithelium (MEE) of both strains at the time of the contact of palatal shelves; the heavier (C57) and milder (MF1) alteration of their presence in the Tgf-b3 null mutants; the importance of TGF-b3 to restore their normal pattern of expression; and the crucial role of fibronectin and the a5-integrin in palatal shelf adhesion. We thus provide insight into the molecular bases of this important process and the cleft palate presented by Tgf-b3 null mutant mice.Fondo de Investigaciones SanitariasComunidad Autónoma de MadridUniversidad ComplutenseDepto. de Anatomía y EmbriologíaFac. de MedicinaTRUEpu