Regeneration research in the Soviet Union.

Over the past 20 years Soviet research in regeneration has undergone a shift in emphasis from work on amphibians to mammals. In that period several distinct schools of thought have arisen, and often there has been considerable controversy as to the nature of certain regenerative processes. At present most mammalian tissues and organs are being studied with respect to natural regenerative capacity and means of stimulating further regeneration. The most striking results have been obtained in the areas of muscle and bone regeneration. Progress in other areas has been less spectacular. Considerable effort has been put into devising means of regenerating functional tissue from pathologically changed or irradiated organs. The field of regeneration research in the Soviet Union is quite highly organized and includes a relatively large number of workers. Progress has, to some extent, been impeded by shortages of equipment and biochemical preparations. For the past 20 years, the development of regeneration research in the Soviet Union has followed a course different from that in other countries. During a recent exchange visit to the U.S.S.R., it became evident to me that much of the Soviet work in this field is not well known by members of the Western scientific community. The following report will present a general outline of the historical development and current areas of emphasis in Soviet work on vertebrate regeneration. HISTORICAL DEVELOPMENT Before the 1930's, Soviet work on regeneration constituted a rather small portion of the total biological research effort, with scattered publications of investigations carried out on vertebrate forms and a lesser number of studies conducted on invertebrates. The rise of the strong school in developmental mechanics under the leadership of D. P. Filatov during the 1920's and 1930's furnished the initial impetus for the active program of regeneration currently underway (Polezhaev, '46a). A number of the leaders in this field today were either trained as experimental embryologists under Filatov or were, at least, considerably influenced by his work. The theoretical basis for many of the investigations taking place during this period was closely allied to the thinking in experimental embryology at that time, and starting in the early 1930's there appeared a large number of papers on the determinaANAT. REC., 160: 665-674. tion, potencies and morphogenesis of the regeneration blastema (Polezhaev, '45; Vorontsova, '49 *; Vorontsova and Liosner, '60) as well as a series of investigations concerned with the role of inductive processes taking place in regeneration and supernumerary limb formation (Fedotov, '46; Nassonov, '41). Of the Russian research during this period, the work of L. v. Polezhaev exerted the greatest influence upon Western biologists. Perhaps the most important contributions were his demonstration that amputated limbs of post-metamorphic frogs can be stimulated to regenerate by severely traumatizing the limb stumps (Polezhaev, '46b) and his early recognition of the importance of epithelialmesodermal interrelationships in amphibian limb regeneration (Polezaiev and Faworina, ' 35 ) . During this period several investigators attempted to delineate the role of individual tissue components of limb and tail stumps with respect to their contribution to and morphogenetic control over the regenerate (Vorontsova and Liosner '60, pp. 39-361). One of the most significant contributions was the demonstration by Umanski ('37) that x-radiated axolotl limbs provided with normal skin produce regenerates whose form reflects the origin of the skin. 1The author spent the period from December 1965 to May 1966 in the Soviet Union under the auspices of the exchange program between the Academies of Sciences of the USA and USSR. ZThis book contains an almost complete bibliography of Soviet regeneration work before 1949.