Book of Abstracts - New Frontiers 2022

Abstracts of poster presentations

LIPOPOLYSACCHARIDE-INDUCED CHANGES IN ENDOTHELIAL CONNEXIN-40 AND OCCLUDIN ASSOCIATED WITH MACROPHAGE INFILTRATION IN BOTH NORMOTENSIVE AND SPONTANEOUSLY HYPERTENSIVE RATS

K. Frimmel , J. Križák, R. Sotníková, V. Knezl, Ľ. Okruhlicová

Centre of Experimental Medicine, Slovak Academy of Sciences, Bratislava, Slovakia

Bacterial endotoxin (LPS) and hypertension were considered as an important pro-atherogenic factor targeting mainly vascular endothelium. The aim of our study was to investigate the effect of LPS on expression of connexin Cx40 (endothelial/conduction system), Cx43 (mainly myocardial) and endothelial tight junctions protein occludin in left ventricle (LV) Wistar (normotensive) and SHR (spontaneously hypertensive) rats. We used adult Wistar and SHR rats injected with a bolus of LPS (E. coli, 1mg/kg, i.p.). LV samples were taken 10 days after. We measured selected inflammatory markers (TNF-a, NFkB) and CD68 as a macrophage marker. Expression of Cx40, occluding and Cx43 were obtained by western blot method and localized with immunohistochemistry method. LPS application to SHR reduce expression both connexins and change redistribution of Cx43 accompanied with extensively increased macrophage infiltration and NFκB and TNF - α expression. Total occ ludin expression was increased in both SHR groups compared to Wistar, while SHR-LPS was higher compared to SHR. Administration of LPS to Wistar rats increased tissue infiltration by macrophages, decrease Cx40 expression. Our results are suggestive of regulation of Cx43, Cx40 and occludin expression with macrophages-related inflammation in the LV of SHR rats. The results also indicate that LV vascular endothelium of SHR rats can be more sensitive to LPS than are normotensive Wistar rats.

Keywords: LPS, hypertension, tight junction, connexin

Funding: VEGA 2/0162/19

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