Topical delivery of TRPsiRNA-loaded solid lipid nanoparticles confer reduced pain sensation via TRPV1 silencing, in rats.

Abstract

Present work describes a novel composition for encapsulating TRPsiRNA (TRPV1-targeting siRNA) within lipid-matrix (4:1::glyceryl behnate:stearic acid) of SLNs, using suitably modified cold high-pressure homogenisation technique. Optimisation of the method and composition conducted using calf-thymus DNA (ctDNA), to avoid cost of TRPsiRNA molecules, resulted in small size (d50 = 50-100 nm) and high entrapment (77.22-98.5%). Complete masking of extreme negative charge of both ctDNA (-34.50 mV) and TRPsiRNA (-23.98 mV) upon encapsulation in SLNs without employing cationic components is reported herein for the first time. Diffusion-controlled release (90.17% at 72 h) from a rigid matrix shifted to porous matrix (at 24 h) due to solubilisation of stearic acid at 37 °C. Efficient in vitro (HEK293 T cells) and in vivo transfection and expression established the proof-of-concept. PEG600 as supporting-surfactant and vitrifying agent promoted small size, effective transfection and rupture of endosomal membrane to affect endosomal escape. Physiological efficacy in terms of significant increase (p < .0001) in paw-withdrawal-latency, following topical and intradermal application of TRPsiRNA-loaded SLNs, in rats, exposed to thermal hyperalgesia (145 and 182%, respectively) and capsaicin-induced pain (155 and 182%, respectively) indicate effective silencing of skin TRPV1. Significant decrease in intensity and duration (one-fifth) of capsaicin-induced nocifensive behaviour was also observed. Naked TRPsiRNA, however, did not show any effect.

• Authors: Gaurav Sharma, Kanwaljit Chopra, Sanjeev Puri, Mahendra Bishnoi, Praveen Rishi, Indu P Kaur
• Journal: Journal of drug targeting (J Drug Target) Vol. 26 Issue 2 Pg. 135-149 (02 2018) ISSN: 1029-2330 [Electronic] England
• PMID: 28670930 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• RNA, Small Interfering
• TRPV Cation Channels
• Trpv1 protein, rat
• Capsaicin

Topics

• Administration, Topical
• Animals
• Capsaicin (toxicity)
• Female
• Gene Silencing
• Pain (chemically induced, prevention & control)
• RNA, Small Interfering
• Rats
• Rats, Wistar
• TRPV Cation Channels (administration & dosage)