Related Experiment Video
Updated: Nov 14, 2025
A Simple and Reproducible Method to Prepare Membrane Samples from Freshly Isolated Rat Brain Microvessels
Published on: May 7, 2018
Protein Nanoparticle-Related Osmotic Pressure Modifies Nonselective Permeability of the Blood-Brain Barrier by
Chen Li1,2, LinLin Chen1,2, YuanYuan Wang1,2
1School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, People's Republic of China.
Background:
Intracellular tension plays a crucial role in the destruction of the blood-brain barrier (BBB) in response to lesion stimuli. Tight junction structure could be primarily affected by tension activity. In this study, we aimed to determine the effects of extracellular BBB damage on intracellular tension activity, and elucidate the mechanism underlying the effects of intracellular protein nanoparticle-related osmotic pressure on BBB permeability.
Methods:
The intracellular tension for tight junction proteins occludin and ZO1 was evaluated using the fluorescence resonance energy transfer (FRET)-based tension probes and cpstFRET analysis. The changes in mobility ratios of occludin were evaluated via the fluorescence recovery after photobleaching (FRAP) test. The cytoplasmic osmotic pressure (OP) was measured using Osmometer. The count rate of cytoplasmic nanoparticles was detected by Nanosight NS300. The activation of cofilin and stathmin was examined by Western blot analysis. The BBB permeability in vivo was determined via the changes of Evans Blue (EB) injected into SD rats. The tight junction formation was assessed by the measurement of transendothelial electrical resistance (TEER). Intracellular calcium or chloride ions were measured using Fluo-4 AM or MQAE dyes.
Results:
BBB lesions were accompanied by changes in occludin/ZO1 tension. Increases in intracellular osmotic pressure were involved in alteration of BBB permeability, possibly through the depolymerization of microfilaments or microtubules and mass production of protein nanoparticles according to the Donnan effect. Recovery of protein nanoparticle-related osmotic pressure could effectively reverse the effects of changes in occludin/ZO1 tension under BBB lesions. Outward tension of intracellular osmotic potential also caused upregulation of membrane fluidity, which promoted nonselective drug influx.
Conclusion:
Our results suggest a crucial mechanical mechanism underlying BBB lesions, and protein nanoparticle-related osmotic pressure could be a novel therapeutic target for BBB lesion-related brain diseases.
Related Concept Videos
00:49The Blood-brain Barrier
01:25Physiological Barriers
The blood endothelial barrier is the most porous of these. It allows all small ionized, un-ionized, and lipophilic molecules to pass through the endothelial lining into the interstitial space...
02:40Osmosis and Osmotic Pressure of Solutions
01:17Pore Transport and Ion-Pair Transport
Pore transport, also known as convective transport, is a process where small molecules like urea, water, and sugars rapidly cross cell membranes as though there were channels or pores in the membrane. Although direct microscopic evidence is limited but the concept of pores or channels is widely accepted based on physiological evidence. Despite the lack of direct...
01:27Bioavailability Enhancement: Drug Permeability Enhancement
01:23Factors Affecting Drug Distribution: Physiological Barriers
The capillary endothelial barrier allows only smaller molecules below 600 Da (Daltons) to pass through. It also restricts drugs like heparin that are bound to blood components, limiting their movement within the bloodstream.
The...