Feline infectious peritonitis (FIP) is an important feline
viral disease, causing an overridden inflammatory response that results in a high mortality rate, primarily in young cats.
Curcumin is notable for its biological activities against various
viral diseases; however, its poor bioavailability has hindered its potential in therapeutic application. In this study,
curcumin was encapsulated in
chitosan nanoparticles to improve its bioavailability.
Curcumin-encapsulated
chitosan (Cur-CS) nanoparticles were synthesised based on the ionic gelation technique and were spherical and cuboidal in shape, with an average particle size of 330 nm and +42 mV in zeta potential. The nanoparticles exerted lower toxicity in Crandell-Rees feline kidney (CrFK) cells and enhanced
antiviral activities with a selective index (SI) value three times higher than that of
curcumin. Feline-specific bead-based multiplex immunoassay and qPCR were used to examine their modulatory effects on proinflammatory
cytokines, including tumour
necrosis factor (TNF)α,
interleukin- (IL-) 6, and IL-1β. There were significant decrements in IL-1β,
IL-6, and TNFα expression in both
curcumin and Cur-CS nanoparticles. Based on the multiplex immunoassay,
curcumin and the Cur-CS nanoparticles could lower the immune-related
proteins in FIP virus (FIPV)
infection. The single- and multiple-dose pharmacokinetics profiles of
curcumin and the Cur-CS nanoparticles were determined by high-performance liquid chromatography (HPLC). Oral delivery of the Cur-CS nanoparticles to cats showed enhanced bioavailability with a maximum plasma concentration (C max) value of 621.5 ng/mL. Incorporating
chitosan nanoparticles to deliver
curcumin improved the oral bioavailability and
antiviral effects of
curcumin against FIPV
infection. This study provides evidence for the potential of Cur-CS nanoparticles as a supplementary treatment of FIP.