Hydrobiologia

, Volume 383, Issue 1–3, pp 111–116 | Cite as

Inhibition of regeneration in the planarian Dugesia polychroa (Schmidt) by treatment with magnesium chloride: a morphological study of wound closure

Abstract

At a concentration of 0.2% (21 m M) in culture water, magnesium chloride impaired muscle contraction and completely inhibited head regeneration in specimens of Dugesia polychroa cut prepharyngeally. The wound stayed open for nine days, with neoblasts accumulating beneath the wound without any signs of differentiation. Extremely delayed wound closure occurred by spreading epithelial cells, and was completed after 30 days in the magnesium chloride solution. Histological examination confirmed the absence of any regenerated head structures. Interestingly, the inhibitory effect was removed when such headless fragments were cut once more and kept in normal culture water: complete head regeneration then occurred at a normal rate. Among several possible explanations for the failure to regenerate, the following hypothesis is an attractive alternative: direct contact between parenchyma and epithelial cells during the period following injury seems to be an essential stimulus for the start of cell differentiation within the blastema, and the lack of such contact as a result of the drug action prevents normal regeneration. When the wound has eventually closed, a continuous basement membrane separates epithelium from parenchyma. Thus a direct contact between these tissues is never established.

Dugesia polychroa magnesium chloride neoblasts planarians regeneration wound healing Platyhelminthes 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Baguñà, J., E. Saló, J. Collet, M. C. Auladell & M. Ribas, 1988. Cellular, molecular and genetic approaches to regeneration and pattern formation in planarians. Fortschr. Zool. 36: 65–78.Google Scholar
  2. Baguñà, J., E. Saló, R. Romero, J. Garcia-Fernàndez, D. Bueno, A. M. Muñoz-Marmol, J. R. Bayascas-Ramirez & A. Casali, 1994. Regeneration and pattern formation in planarians: Cells, molecules and genes. Zool. Sci. 11: 781–795.Google Scholar
  3. Benazzi, M. & G. Benazzi-Lentati, 1976. Platyhelminthes. Animal Cytogenetics, Vol. 1, B. John (ed.), Gebrüder Borntraeger, Berlin.Google Scholar
  4. Betchaku, T., 1967. Isolation of planarian neoblasts and their behavior in vitro with some aspects of the mechanism of the formation of regeneration blastema. J. exp. Zool. 164: 403–434.CrossRefGoogle Scholar
  5. Brøndsted, H.V., 1969. Planarian regeneration. Pergamon Press, Oxford.Google Scholar
  6. Goss, R.J., 1969. Principles of regeneration. Academic Press Inc., New York.Google Scholar
  7. Goss, R.J., 1980. Prospects for regeneration in man. Clin. Orthopaed. Rel. Res. 151: 270–282.Google Scholar
  8. Gremigni, V., 1981. The problem of cell totipotency, dedifferentiation and transdifferentiation in Turbellaria. Hydrobiologia 84: 171–179.CrossRefGoogle Scholar
  9. Gremigni, V., 1988. Planarian regeneration: an overview of some cellular mechanisms. Zool. Sci. 5: 1153–1163.Google Scholar
  10. Hori, I., 1978. Possible role of rhabdite-forming cells in cellular succession of the planarian epidermis. J. Electron Microsc. 27: 89–102.Google Scholar
  11. Hori, I., 1979. Structure and regeneration of the planarian basal lamina: An ultrastructural study. Tissue & Cell 11: 611–621.CrossRefGoogle Scholar
  12. Hori, I., 1989. Observations on planarian epithelization after wounding. J. Submicrosc. Cytol. Pathol. 21: 307–315.PubMedGoogle Scholar
  13. Lender, Th., 1962. Factors in morphogenesis of regenerating freshwater planaria. Advances in Morphogenesis, 2. Academic Press Inc., New York: 305–331.Google Scholar
  14. Lillie, R.D., 1954. Histopathologic Technic and Practical Histochemistry. Blakiston and Co., New York.Google Scholar
  15. McConnell, J.V., 1967. A Manual of Physiological Experimentation on Planarians. Planarian Press, Ann Arbor, Mich. U.S.A.Google Scholar
  16. Morita, M. & J.B. Best, 1974. Electron microscopic studies of planarian regeneration. II. Changes in epidermis during regeneration. J. exp. Zool. 187: 345–374.PubMedCrossRefGoogle Scholar
  17. Pedersen, K. J., 1959. Cytological studies on planarian neoblasts. Z. Zellforsch. 50: 799–817.PubMedCrossRefGoogle Scholar
  18. Prusch, R. D., 1976. Osmotic and ionic relationships in the freshwater flatworm, Dugesia dorotocephala. Comp. Biochem. Physiol. 54A: 287–290.Google Scholar
  19. Rieger, R. M., W. Salvenmoser, A. Legniti & S. Tyler, 1994. Phalloidin-rhodamine preparation of Macrostomum hystricinum marinum (Plathelminthes): morphology and postembryonic development of the musculature. Zoomorphology 114: 133–147.CrossRefGoogle Scholar
  20. Schürmann, W. & R. Peter, 1988. Isolation and cultivation of planarian neoblasts by a novel combination of methods. Fortschr. Zool. 36: 111–114.Google Scholar
  21. Singer, M. & M. M. Salpeter, 1961. Regeneration in vertebrates: the role of the wound epithelium. In M. X. Zarrow (ed.), Growth in Living Systems. Basic Books, New York: 277–311.Google Scholar
  22. Thornton, C.S., 1968. Amphibian limb regeneration. In Advances in Morphogenesis, 7. Academic Press Inc., New York: 205–249.Google Scholar

Copyright information

© Kluwer Academic Publishers 1998

Authors and Affiliations

  1. 1.Department of Genetics and General BiologyUniversity of SalzburgSalzburgAustria

Personalised recommendations