Biological effects of bacterial pigment undecylprodigiosin on human blood cells treated with atmospheric gas plasma in vitro

Abstract

It is known that some bacterial species are more resilient to different kinds of irradiation due to the naturally developed protective mechanisms and compounds such as pigments. On the other hand, reasoned tissue engineering using plasma remains a critical task and requires very precise control of plasma parameters in order to mitigate its potential detrimental effects. Here we isolated a natural protective agent, microbially produced undecylprodigiosin ((5'Z)-4'-methoxy-5'-[(5-undecyl-1H-pyrrol-2-yl)methylene]-1H,5'H-2,2'-bipyrrole), and investigated its effects on human blood cells independently and in combination with plasma. Two approaches were applied; the first, undecylprodigiosin (UP pigment) was added to the blood cultures, which then were exposed to plasma (pre-treatment); and the second- the blood cultures were exposed to plasma and then treated with pigment (post-treatment). The interactions of plasma and UP pigment with blood cells were investigated by conducting a series of biological tests providing the information regarding their genotoxicity, cytotoxicity and redox modulating activities. The exposure of cells to plasma induced oxidative stress as well as certain genotoxic and cytotoxic effects seen as elevated micronuclei incidence, decreased cell proliferation and enhanced apoptosis. In blood cultures treated with UP pigment alone, we found that both cytotoxic and protective effects could be induced depending on the concentration used. The highest UP pigment concentration increased lipid peroxidation and the incidence of micronuclei by more than 70% with maximal suppression of cell proliferation. On the contrary, we found that the lowest UP pigment concentration displayed protective effects. In combined treatments with plasma and UP pigment, we found that UP pigment could provide spatial shielding to plasma exposure. In the pre-treatment approach, the incidence of micronuclei was reduced by 35.52% compared to control while malondialdehyde level decreased by 36% indicating a significant mitigation of membrane damage induced by plasma. These results open perspectives for utilizing UP pigment for protection against overexposures in the field of plasma medicine.

Keywords: Atmospheric pressure gas plasma; Free radicals; Genotoxicity; Undecylprodigiosin.