Perilla extract improves frequent urination in spontaneously hypertensive rats with enhancement of the urothelial presence and anti‐inflammatory effects

Objective

To investigate the effects of perilla extract on urinary symptoms in spontaneously hypertensive rats as a model of spontaneous overactive bladder.

Methods

Spontaneously hypertensive rats were randomly divided into two groups and fed either a control diet or a perilla extract‐containing diet. Cystometry, gene expression and histological analyses were carried out to evaluate the effects of perilla extract after 2‐week feeding of either the control or the perilla extract diet. The expression of inflammation‐related genes in the human urothelial cell line HT‐1376 and the normal human bladder epithelial cell was measured after the treatment with perillaldehyde, the main component of perilla extract, or perillic acid, the final metabolite of perillaldehyde.

Results

A significant 27% increase in the micturition interval and decreased expression of nerve growth factor, tumor necrosis factor‐α, interleukin‐1β and transient receptor potential V1 were observed in the perilla group compared with the control group. The level of uroplakin 3A was 40% higher in the perilla group than in the control group. The urothelium in the control group was thin or defective, but it was almost completely intact in the perilla group. Perillaldehyde and perillic acid suppressed the induction of nerve growth factor and tumor necrosis factor‐α by interleukin‐1β in HT‐1376 and normal human bladder epithelial cells.

Conclusions

The present findings suggest that perilla extract improves frequent urination, and this improvement seems to be mediated, at least in part, by enhancement of the urothelial presence and by the anti‐inflammatory effects of perilla.