Silicone Oil Promotes The Aggregation Of Amyloid Proteins And Peptides

Amyloid Diseases have attracted many scientists’ interest, and were called theEighth Wonder of the World by Igor K. Lednev. Since1994, there have beensuccessive articles reported on the effects of the interfacial hydrophilicity/hydrophobicity on the aggregation of amyloid proteins and peptides. Proteinmonomer not only gathers at the hydrophilicity/hydrophobicity interfaces, but alsoadopts a corresponding conformation and a suitable arrangement that are beneficialto aggregating at the interface. It has been reported that even macroscopic gas-liquidinterfaces can remarkably promote the aggregation of amyloid protein α-Syn.Silicone oil is a kind of polysiloxane, which is hydrophobic, and has beenwidely used in industry, medical treatment and daily supplies. It is usuallyconsidered harmless to human body. For example, in eye surgeries and aestheticsurgeries, we usually use silicone oil as filler. It forms a hydrophobic interface whenthe silicone oil particles present in the water. Though silicon oil is wildly used inmedical, currently there are no literatures that reported the effects of silicone oil onthe aggregation of the amyloid proteins and peptides, which may lead to severediseases.This thesis studied the effects of silicon oil on the peptide aggregation by in situmeasurement of the fluorescence of thioflavin T (ThT) during peptide aggregationand topological analysis of the aggregated peptide nanostructures by atomic forcemicroscopy (AFM). In total five peptides were studied, including Acp11peptide,α-Syn, Amyloid protein (Human Aβ42), Yeast Prion protein Ure2and GAV9peptide.Results indicated that these amyloid proteins/peptides aggregated faster and moresufficiently in the solutions containing silicone oil.The above-mentioned results indicate we need to consider the medical andbiological effects of silicon oil that normally coats on the internal surface ofcentrifuge tubes, which are widely used as containers in the biomedical fields. Sincevibration of aqueous solutions in normal containers would result in desorption ofsilicon oil from the container wall, the influence of the desorbed silicon oil on theaggregation of amyloid samples was investigated. The results showed that thedesorbed oil also promoted the aggregation of amyloid peptides.The effects of silicon oil on the aggregation of amyloid proteins/peptides inspire us to consider the possible pathogenesis of some severe disease. For example,silicone oil would normally be used as filler after eye surgery, which would verylikely lead to complications including cataract. The pathogenesis is not yet clear.Since the occurrence of cataract has a close relationship to the aggregation of lensprotein(Crystallin), it is reasonable for us to speculate that eye surgery complicationssuch as cataract after silicon oil filling may be induced by silicone oil-promotedprotein aggregation.