Erythrocytes modulate cell cycle progression but not the baseline frequency of sister chromatid exchanges in pig lymphocytes

Abstract

The effect of co-culturing varying concentrations of pig and human red blood cells (RBCs) on the baseline frequency of sister chromatid exchanges (SCEs) and cell-cycle progression in pig plasma (PLCs) and whole blood leukocyte cultures (WBCs) was studied. No variation in SCE frequency was observed between pig control WBC and PLC. Addition of pig and human RBCs to pig PLCs did not modify the baseline frequency of SCEs. On the other hand, cell proliferation was slower in PLCs than in WBCs. The addition of pig or human RBCs to PLCs accelerated the cell-cycle progression of pig lymphocytes. When RBCs were added to PLCs the concentration and time sequence of RBC incorporation affected the cell-cycle progression of swine lymphocytes. When doses of pig or human RBCs equivalent to those present in WBCs were added immediately after PLC stimulation, the cell-cycle kinetics were similar to those of WBCs. Shorter co-incubation periods or a reduction in the dose of RBCs made cell-cycle progression intermediate between PLC and WBC values. Thus, pig and human RBCs modulated the in vitro cell-cycle progression of pig lymphocytes in a time- and dose-dependent manner, and the low baseline frequency of SCEs of pig lymphocytes is independent of the presence or absence of erythrocytes in culture<br>Foi estudado o efeito de co-culturas com concentrações variadas de células sangüíneas vermelhas (RBCs) suínas e humanas na freqüência basal de trocas de cromátides irmãs (SCEs) e na progressão do ciclo celular em culturas de plasma de porco (PLCs) e culturas leucocitárias do sangue total (WBCs). Não foi observada nenhuma variação na freqüências de SCEs entre os controles de WBC e PLC em porcos. A adição de RBCs de suínos e humanos a PLCs não modificou a freqüência basal de SCEs. Por outro lado, a proliferação celular foi mais lenta em PLCs que em WBCs. A adição de RBCs humanas ou suínas a PLCs acelerou a progressão do ciclo celular de linfócitos suínos. Quando RBCs foram adicionadas a PLCs, a concentração e a seqüência temporal da incorporação de RBC afetaram a progressão do ciclo celular de linfócitos suínos. Quando adicionadas doses de RBCs suínas ou humanas equivalentes àquelas presentes em WBCs, imediatamente após estimulação da PLC, a cinética do ciclo celular foi similar à das WBCs. Períodos mais curtos de co-incubação ou uma redução na dose de RBCs causaram uma progressão do ciclo celular intermediária entre os valores de PLCs e WBCs. Assim, RBCs suínas e humanas modularam a progressão do ciclo celular in vitro de linfócitos suínos em uma maneira dependente da dose e do tempo, e a freqüência basal baixa de SCEs de linfócitos suínos independe da presença ou não de eritrócitos na cultur

Monocytes affect cell‐cycle progression but not baseline frequency of sister chromatid exchanges of pig lymphocytes

“…1). These observations were previously reported by us, confirming that pig lymphocytes in erythrocyte-free cultures proliferate slower than parallel WBC cultures [Larramendy et al, , 1993[Larramendy et al, , 1995Reigosa et al, 1997]. Similar findings were also observed previously in human [Larramendy et al, , 1996Mehnert et al, 1984] as well as rat lymphocytes [Wilmer et al, 1983[Wilmer et al, , 1984.…”

“…These results demonstrate that, regardless of donor or culture type, SCE baseline frequency of pig lymphocytes is not modulated by the presence or absence of red blood cells in the culture, nor by the concentration of the MNs seeded in the medium. These observations confirm and verify the homogeneous response of pig lymphocytes independent of whether they were cultured together with red blood cells or not, as reported previously [Larramendy and Reigosa, 1986;Larramendy et al, , 1993Larramendy et al, , 1995Reigosa et al, 1997]. However, these earlier studies did not address the effect of MN concentration on SCE frequency.…”

“…We observed that pig and human RBCs modulated the in vitro cell-cycle progression of pig lymphocytes in a time-and dose-dependent manner, and that the low baseline frequency of SCEs of pig lymphocytes was independent of the presence or absence of erythrocytes in the culture [Reigosa et al, 1997].…”

“…In order to make intra-and interspecies comparisons, standardized protocols are required to exclude experimental sources of variation. Spontaneous SCE induction and wide variability in the baseline frequency of exchanges and cell-cycle kinetics are problems that have been addressed by several authors [Carrano et al, 1980;Gebhart, 1981;Larramendy and Reigosa, 1986;Larramendy et al, , 1993Larramendy et al, , 1996Latt et al, 1980;Reigosa et al, 1997]. Factors that so far have been observed to influence both SCE frequency and the proliferation rate of mammalian lymphocytes cultured in vitro are the concentration of bromodeoxyuridine [Carrano et al, 1980;Davidson et al, 1980;Kato, 1977;Kligerman et al, 1982;Lambert et al, 1976;Latt, 1974;Morgan and Wolff, 1984], growth temperature [Abdel-Fadil et al, 1982;Gutierrez et al, 1981;Kato, 1980;Speit, 1980], serum [Bianchi et al, 1979;Ghosh and Nand, 1979;Kato, 1977;Kato and Sandberg, 1977;Larramendy et al, 1993;McFee and Sherill, 1981;Mutchinick et al, 1980], plasma [Larramendy et al, 1993], culture media [Bianchi et al, 1979[Bianchi et al, , 1981, and the number of leukocytes [Kligerman et al, 1982] and red blood cells (RBCs) as well [Larramendy and Reigosa, 1986;Larramendy et al, , 1996Mehnert et al, 1984;Reigosa et al, 1997].…”

“…Even when the above-mentioned sources of variation are excluded or minimized, baseline SCE frequencies and cell-cycle progression of the same lymphocytes have been reported to vary in these three culture types from humans [Larramendy and Reigosa, 1986;Larramendy et al, , 1993Larramendy et al, , 1995Larramendy et al, , 1996Ray and Altenburg, 1978], pigs [Larramendy and Reigosa, 1986;Larramendy et al, , 1993Larramendy et al, , 1995Larramendy et al, , 1996Reigosa et al, 1997], and rats [Kligerman et al, 1982;Wilmer et al, 1983Wilmer et al, , 1984.…”