Influence of puerarin, paeoniflorin, and menthol on structure and barrier function of tight junctions in MDCK and MDCK-MDR 1 Cells

Abstract

To find out how the drugs cross the blood-brain barrier (BBB), this study examined how puerarin, paeoniflorin, and
menthol affected the structure and function of tight junctions (TJs) in MDCK and MDCK-multidrug resistance 1
(MDR1) cells.
The cells were first treated with puerarin, paeoniflorin, and menthol. Then, they were stained with occludin, claudin-
1, and F-actin using immunohistochemistry. Next, laser-scanning confocal microscopy was used to examine the cells.
An epithelial voltage voltmeter was used to assess transepithelial electrical resistance (TEER), and ImageJ software
was used to analyse the average optical density (AOD) of the protein immunofluorescence pictures.
The results showed that tight junction proteins treated with puerarin and paeoniflorin were visible under confocal
microscopy, but menthol reduced their expression. Similarly, the menthol group's AOD value was downregulated,
while the control group's value was not different from the AOD values of cells treated with either puerarin or
paeoniflorin, or both. After three hours, the TEER of cells that were not exposed to menthol were comparable to those
of the control group, but treatment with
With a p-value less than.05, menthol considerably reduced the TEER score. And menthol's TEER-lowering effects
on MDCK cells were noticed before those on MDCK-MDR1 cells.
Ultimately, it seems that menthol, in contrast to puerarin and paeoniflorin, has the potential to decrease the barrier
function of TJs, which in turn enhances paracellular transport and drug penetration of the blood-
brain barrier.