Combination of Luteolin and Solifenacin Improves Urinary Dysfunction Induced by Diabetic Cystopathy in Rats

BACKGROUND The purpose of the present study was to assess the effect of luteolin and solifenacin on diabetic cystopathy (DCP) and to investigate the mechanism of action. A novel link between the overexpression of c-Kit in the bladder and voiding dysfunction was identified in rats with DCP. MATERIAL AND METHODS A rat model of DCP was successfully established by intraperitoneal injection of streptozotocin and a diet high in glucose and lipids, and animals were treated with luteolin and solifenacin. The effect of luteolin and solifenacin on urinary dysfunction in DCP rats was investigated by assessing bladder pressure and performing a volume test. The protein levels of c-Kit, stem cell factor (SCF), p110, and phosphorylated p110 in the bladder were detected by Western blot analysis and immunohistochemical staining. RESULTS In DCP rats, the protein levels of c-Kit, SCF and phosphorylated p110 in the bladder were significantly increased. However, oral treatment of DCP rats with luteolin combined with solifenacin resulted in effective improvement of overactive bladder and reduced the protein expression of c-Kit, SCF, and phosphorylated p110. Moreover, the effect of luteolin combined with solifenacin on maximum voiding pressure and residual urine volume was improved compared to that of luteolin alone. CONCLUSIONS Luteolin improved overactive bladder in DCP rats, which may be due to SCF/c-kit inhibition, as well as the downregulation of the phosphoinositide-3 kinase signaling pathway. Moreover, solifenacin enhanced the potential pharmacological effect of luteolin in the treatment of DCP.