RESUMO
We have studied radiolabelled plasmid DNA biodistribution and degradation in the muscle at different times after injection, with or without electrotransfer using previously defined conditions. Radiolabelled plasmid progressively left the muscle and was degraded as soon as 5 min after plasmid injection, with or without electrotransfer. Autoradiography showed that the major part of injected radioactivity was detected in the interfibrilar space of a large proportion of the muscle. Large zones of accumulation of radioactivity, which seems to be contained in some fibres (more than 20 microm), were identified as soon as 5 min after electrotransfer. Such structures were never observed on slices of non-electrotransferred muscles. However, these structures were not frequent and probably lesional. The surprising fact is that despite the amount of intact plasmid having been greatly reduced between 5 min and 3 h after injection, the level of transfection remains unchanged whether electric pulses were delivered 20 s or 3 h after injection. Such a behavior was similarly observed when injecting 0.3, 3 or 30 microg of plasmid DNA. Moreover, the transfection level was correlated to the amount of plasmid DNA injected. These results suggest that as soon as it is injected, plasmid DNA is proportionally partitioned between at least two compartments. While a major part of plasmid DNA is rapidly cleared and degraded, the electrotransferable pool of plasmid DNA represents a very small part of the amount injected and belongs to another compartment where it is protected from endogenous DNAses.
Assuntos
DNA/metabolismo , Músculo Esquelético/metabolismo , Plasmídeos/farmacologia , Animais , Autorradiografia , DNA/análise , DNA/isolamento & purificação , Desoxirribonuclease I/farmacologia , Eletroforese , Eletroporação , Feminino , Amplificação de Genes , Genes Reporter , Injeções Intramusculares , Camundongos , Camundongos Endogâmicos C57BL , Fibras Musculares Esqueléticas/química , Fibras Musculares Esqueléticas/metabolismo , Plasmídeos/administração & dosagem , Plasmídeos/análise , Fatores de Tempo , Transfecção/métodos , Trítio/análiseRESUMO
PIP: Results from the 1990 census of France are used to analyze recent population trends in Lorraine, focusing on changes in spatial distribution. Two contradictory trends are noted: firstly, the concentration of population into the major urban centers, and secondly, movement from the cities to rural suburban areas. (SUMMARY IN ENG)^ieng