What Is the Cause of Toxicity of Silicone Oil?

Abstract

Purpose: To investigate the toxicity of the low-molecular-weight components (LMWCs) in ophthalmic silicone oils (SilOils) on retinal cell lines. Methods: The toxicity of six types of LMWCs were studied and compared with conventional SilOil 1000 cSt. In vitro cytotoxic tests of LMWCs, in both liquid and emulsified forms, on three retinal cell lines (Müller cells (rMC-1), photoreceptor cells (661W) and retinal pigment epithelial cells (ARPE-19)) were conducted using a transwell cell culturing system. The morphology and viability of cells were assessed by light microscopy and Cell Counting Kit-8 (CCK-8) assay at different time points (6, 24 and 72 h). The ARPE-19 apoptotic pathway was investigated by Mitochondrial Membrane Potential/Annexin V Apoptosis Kit at different time points (6, 24 and 72 h). Results: Apart from dodecamethylpentasiloxane (L5), all liquid LMWCs showed varying degrees of acute cytotoxicity on retinal cell lines within 72 h. Emulsified LMWCs showed comparable cytotoxicity with liquid LMWCs on retinal cell lines. Cyclic LMWCs, octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) had significantly higher cytotoxicity when compared with their linear counterparts decamethyltetrasiloxane (L4) and L5 with similar molecular formula. Using ARPE-19 cells as an example, we showed that LMWCs induce the apoptosis of retinal cells. Conclusions: Most LMWCs, in both liquid and emulsified forms, can induce acute cytotoxicity. In addition, cyclic LMWCs are suspected to have higher cytotoxicity than their linear counterparts. Therefore, LMWCs are suspected to be the main cause of the long-term toxicity of ophthalmic SilOil, due to their toxicity and propensity to cause ophthalmic SilOil to emulsify. The amount of LMWCs should be considered as the paramount parameter when referring to the quality of SilOil.

Fibrinogen Deposition on Silicone Oil-Infused Silver-Releasing Urinary Catheters Compromises Antibiofilm and Anti-Encrustation Properties

“…As shown in Figure , the SiR catheters after silicone oil infusion showed a decrease in viable cells ( p < 0.05). A similar finding has also been reported by Handa et al A recent study revealed that most silicone oil contains chemical impurities (e.g., low-molecular-weight components) that may diffuse into cells and cause cytotoxicity, but definitive clinical evidence of silicone oil toxicity is still lacking. The silver deposition on either SiR or SiO catheters induced no significant decrease in viable cells ( p > 0.05) despite the fact that the AgO catheters released a relatively higher level of Ag + within 24 h (Figure h).…”

Vitreous Substitutes from Bench to the Operating Room in a Translational Approach: Review and Future Endeavors in Vitreoretinal Surgery

“…However, once coated by surfactants, the small droplets may remain dispersed and sneak through retinal tears into the subretinal space or the zonules in the anterior segment [ 9 , 19 , 59 , 60 ]. This phenomenon can lead to other complications such as inflammation, corneal endothelial damage, high IOP, glaucoma, optic neuropathy and even retinal toxicity [ 61 , 62 ].…”

“…PDMS’s quality and purification is crucial for obtaining a stable and non-toxic SiO for use in vitreoretinal surgery, and it is today known that SiOs can have a low long-term toxic effect on the eye tissues, and even to the tissues surrounding the eye globe. Finding a solution to that is still an ongoing topic of research [ 62 , 91 , 92 , 93 ].…”

Retinal and Corneal Changes Associated with Intraocular Silicone Oil Tamponade

“…In particular, LMWC, short-chain siloxane oligomers or polymers, have long been investigated due to their potentially harmful properties, being able to act as emulsifiers of SO and to diffuse from the vitreous cavity into ocular tissues [ 44 ]. Moreover, three of them, namely the cyclic LMWCs, octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6), have been recognized as toxic by the European Chemicals Agency ( , accessed on 30 May 2022) and show acute cytotoxicity in vitro at high concentration [ 45 ]. Despite the fact that, when testing a concentrate of LMWC with MW up to 1557 g/mol, no acute cytotoxic effect was detected, the long-term effects of these compounds are still unknown [ 46 ].…”