FIG. 4.

Intracellular peroxide levels in human endothelial cells infected with R. rickettsii and cultivated in medium with or without supplementation with α-lipoic acid. The data are presented as means ± standard errors (for three dishes per experimental variable). (a) Time course of intracellular peroxide level changes in infected HUVEC; (b) effect of different concentrations of α-lipoic acid on intracellular peroxide levels at 72 h after infection. The statistical significance of the variables compared is given in the text.