Teratogeni učinki retinojske kisline na razvoj zarodkov španskega pupka (Pleurodeles waltl)

Naiaretto, Sabrina (author), Bizjak Mali, Lilijana (mentor)

Retinojska kislina (RA) je pomemben morfogen med embrionalnim razvojem vretenčarjev. Njena kompleksna in večnivojska vloga je ključna za pravilno vzpostavitev telesnih osi in pravilen potek morfogeneze. Hkrati pa previsoka koncentracija RA v določenih razvojnih stopnjah deluje teratogeno. Namen te študije je bil ugotoviti učinke eksogene RA na zgodnji razvoj španskega pupka (Pleurodeles waltl). Zarodke v stadiju blastule in gastrule smo izpostavili različnim koncentracijam RA (10-6 M, 10-8 M, 10-10 M, 10-11 M) za krajši in daljši čas (1 uro in 24 ur). Spremljali smo teratogene učinke RA na embrionalni razvoj in razvoj ličink ter preživetje. Narejena je bila tudi histološka analiza. Naša opažanja kažejo, da so učinki RA odvisni od razvojnega stadija ob izpostavitvi, od dodane koncentracije RA in dolžine izpostavljenosti RA. Letalne razvojne nepravilnosti smo opazili pri najvišji koncentraciji RA (10-6 M RA) in pri 24-urni izpostavitvi blastul in gastrul, kot tudi pri 1-urni izpostavitvi gastrul. Pri blastulah se je razvoj zaustavil po zaključku nevrulacije, ki je potekala nepravilno in pri gastrulah (24 ur) med zgodnjo organogenezo, medtem ko je bil čas preživetja gastrul izpostavljenih 1 uro med dvemi tedni in enim mesecem. Najhujše motnje v razvoju preživelih zarodkov so bile opažene ob 24-urni izpostavitvi RA v koncentraciji 10-8 M v času gastrulacije. Prizadet je bil razvoj glave in možganov (posteriorizacija z izgubo anteriornega dela), oči (anoftalmija, mikroftalmija, kiklopija, manjkajoča leča), čeljusti, žrela in škrg. Telesna os je bila kratka z ukrivljenim in razcepljenim repom. Pri nižjih koncentracijah RA (10-10 M, 10-11 M) večjih nepravilnosti v razvoju nismo zasledili ne glede na dolžino in razvojni stadij izpostavitve RA. Učinek eksogene RA na razvoj španskih pupkov je podoben ostalim vretenčarskim modelnim organizmom.

• Language: Slovenian
• Keywords: španski pupek, retinojska kislina, morfogen, teratogen, embriogeneza, histologija
• Work type: Master's thesis/paper
• Organization: BF - Biotechnical Faculty
• Year: 2020
• PID: 20.500.12556/RUL-116678
• COBISS.SI-ID: 44399363
• Publication date in RUL: 03.06.2020

Secondary language

• Language: English
• Title: Teratogenic effects of retinoic acid on embryos of Spanish ribbed newt (Pleurodeles waltl, Salamandridae)

Abstract

Retinoic acid (RA) is an important morphogen during the development of vertebrate embryos. Its complex and pleiotropic role is crucial for the correct establishment of the body axes and the proper course of further morphogenesis. It can also act teratogenic if its concentration is higher than normal or if it is present at the wrong time. The purpose of this study was to determine the effects of exogenous RA on early embryonic development in the Spanish ribbed newt (Pleurodeles waltl). Developing embryos at either the blastula or gastrula stage were exposed to different concentrations of RA (10-6 M, 10-8 M, 10-10 M, 10-11 M) for shorter and longer periods (1 hour and 24 hours). The teratogenic effects of RA on embryonic and larval development and survival were monitored. Histological analysis was also performed. Our observations show that the effects of RA on embryonic development in this species depend on the stage of development at exposure, the concentration of RA added, and also on the length of exposure in RA. Lethal developmental abnormalities were observed at the highest concentration (10-6 M RA) for blastulas and gastrulas exposed for the longest time (24 hours) and as well at 1 hour gastrula exposure. In blastulas, development stopped after neurulation while gastrulas stopped during early organogenesis, whereas gastrulas exposed for 1 hour survived from two weeks to one month. Among the surviving embryos, the most severe developmental abnormalities were observed in embryos exposed to 10-8 M RA for 24 hours during gastrulation. Our observations indicate that RA affected the development of head and brain (posteriorization with loss of the anterior parts), eyes (anophthalmia, microphthalmia, cyclopia, missing lens), jaws, pharynx and gills. The body axis was shortened with a bent and forked tail. No major developmental abnormalities were observed at lower concentrations of RA (10-10 M, 10-11 M), and regardless of the length of exposure or developmental stage. These effects of exogenous RA on the development of the Spanish ribbed newt are similar to that observed in other vertebrate model organisms.

• Keywords: spanish ribbed newt, retinoic acid, morphogen, teratogen, embryogenesis, histology