Pharmacological Effects of Methotrexate and Infliximab in a Rats Model of Diet-Induced Dyslipidemia and Beta-3 Overexpression on Endothelial Cells

Background: Hyperlipidemia and inflammation are critical components in the pathophysiology of endothelial disorder, which can lead to vascular complications. Our study aimed to evaluate the effects of immunomodulatory therapy (methotrexate and infliximab) in a diet-induced hyperlipidemia rat model. Methods: Sprague-Dawley (wild type (WT), male, n = 32) rats were divided into four groups: one group fed with standard diet (SD), one group fed with high lipid diet (HLD), and two groups that received HLD and drug treatment (methotrexate (Mtx) or infliximab (Ifx)). In order to evaluate if modifications to the endothelial cells may influence the risk of vascular complications following hyperlipidemia or treatment reactivity, each group was doubled by a rats group that overexpressed beta-3 receptors on the endothelial cells (transgenic (TG-beta 3), male, n = 32). Serum lipid profile, liver enzymes, oxidative stress, and inflammation markers were determined. Histopathologic analysis of the liver and aorta was performed. Results: After 9 weeks of HLD, rats exhibited significant pathologic serum lipid profiles, elevated oxidative stress, and pro-inflammatory markers. Additionally, the aortic histopathological analysis revealed aorta media-intima thickening (p < 0.05) in the transgenic group. Methotrexate and infliximab significantly decreased inflammation and oxidative stress parameters, but presented opposing effects on lipid profiles (methotrexate decreased, whereas infliximab increased the atherosclerosis index). Drug treatment decreased the aorta media-intima thickness (p < 0.05) only in transgenic rats. Conclusions: HLD was associated with hyperlipidemia, inflammation and oxidative stress. The overexpression of beta-3 receptors on endothelial cells increased aortic thickening in response to the HLD. Methotrexate and infliximab reduced oxidative stress and inflammation in all groups, but led to favorable histopathologic vascular results only in the transgenic groups.