Cell viability in the cadmium-stressed cell suspension cultures of tobacco is regulated by extracellular ATP,possibly by a reactive oxygen species-associated mechanism

Cadmium(Cd)is one of the most widespread and toxic heavy metals to plants.Extracellular ATP(exATP)is thought to be an extracellular effector in regulating the physiological responses of plant cells to environmental stresses.However,the function of exATP in Cd-stressed plant cells is much unknown.The present work showed that treating tobacco(Nicotiana tabacum L.cv.Bright Yellow-2)cell-suspension cultures with exogenous CdCl2 reduced the cell viability,exATP level,and Mg content.However,the production of reactive oxygen species(ROS),Cd content,and electrolyte leakage of the cells were enhanced by exogenous CdCl2.When the Cd-induced accumulation of ROS was decreased by the supplement with DMTU(dimethylthiourea,a scavenger of ROS),the Cd-induced increases of the electrolyte leakage and Cd content were alleviated,and the Cd-induced reductions of cell viability were partly rescued,suggesting that Cd-induced reduction of cell viability could be related to the ROS accumulation.Under the condition of Cd stress,when the reduction of exATP level was partly rescued by exogenous ATP(20μM),the increases of ROS production,electrolyte leakage,and Cd content were attenuated,and the reduction of cell viability was also alleviated.These observations indicate that exATP can regulate the cell viability in the Cd–stressed plant cells possibly by an ROS-associated mechanism.

Two-stage degradation and novel functional endothelium characteristics of a 3-D printed bioresorbable scaffold

Bioresorbable scaffolds have emerged as a new generation of vascular implants for the treatment of atherosclerosis,and designed to provide a temporary scaffold that is subsequently absorbed by blood vessels over time.Presently,there is insufficient data on the biological and mechanical responses of blood vessels accompanied by bioresorbable scaffolds(BRS)degradation.Therefore,it is necessary to investigate the inflexion point of degradation,the response of blood vessels,and the pathophysiological process of vascular,as results of such studies will be of great value for the design of next generation of BRS.In this study,abdominal aortas of SD rats were received 3-D printed poly-l-actide vascular scaffolds(PLS)for various durations up to 12 months.The response of PLS implanted aorta went through two distinct processes:(1)the neointima with desirable barrier function was obtained in 1 month,accompanied with slow degradation,inflammation,and intimal hyperplasia;(2)significant degradation occurred from 6 months,accompanied with decreasing inflammation and intimal hyperplasia,while the extracellular matrix recovered to normal vessels which indicate the positive remodeling.These in vivo results indicate that 6 months is a key turning point.This“two-stage degradation and vascular characteristics”is proposed to elucidate the long-term effects of PLS on vascular repair and demonstrated the potential of PLS in promoting endothelium function and positive remodeling,which highlights the benefits of PLS and shed some light in the future researches,such as drug combination coatings design.