Capsaicin-Induced Apoptosis in MBT-2 Murine Bladder Tumor Cells and Bladder Wall Penetration Effect of the Nano-Encapsulated Capsaicin in Rabbit

Abstract

In this study, we attempted to characterize capsaicin's effects with regard to the apoptosis of murine bladder cancer cells (MBT-2) as well as the pharmacodynamics of nano-encapsulated capsaicin formulation for intravesical instillation. Materials and Methods: We assessed the viability of the MBT-2 cells via MTT staining, agarose gel electrophoresis, and flow cytometric apoptosis analysis. Intravesical reagents were instilled into 3 groups of male white New Zealand rabbits. Instillation agents were nano-encapsulated capsaicin dissolved in saline, capsaicin dissolved in saline, and capsaicin dissolved in dimethyl sulfoxide (DMSO). We also determined the pharmacokinetics of urine, plasma, and bladder tissue after intravesical capsaicin instillation. Results: Capsaicin treatment was determined to reduce cell viability in a time-and dose-dependent manner. The capsaicin concentrations in the urine of the rabbits decreased in each of the treatment groups, but we noted a more profound reduction of capsaicin concentration in the nano-encapsulated capsaicin group. Plasma concentrations were definitely lower as compared with the levels measured in the bladder tissue and urine. We noted distinctive differences in patterns of concentration change between the capsaicin with normal saline solution (NSS) or DMSO and the nano-encapsulated capsaicin groups. The concentration of nano-encapsulated capsaicin in the tissue appeared to increase directly with tissue depth. Conclusions: Our results show that capsaicin can induce apoptosis in MBT-2 cells, as well as the excellent permeation properties of nano-encapsulated capsaicin. Treatment with intravesical capsaicin may be a promising alternative therapeutic modality for the treatment of bladder cancer.