ABSTRACT
BACKGROUND: Despite enormous progresses in understanding pathophysiology of the lower urinary tract, antimuscarinics remain the chief clinically well-established approach for improving symptoms of overactive bladder (OAB). Dry mouth on the other hand remains one of the most untolerated systemic side effects of these drugs that limits their uses and results in high discontinuation rate. Three novel drugs have been recently approved by US Food and Drug Administration for treatment of OAB: trospium, darifenacin, and solifenacin. AIMS: This study has been conducted to provide clear head to head comparative studying of histological and ultrastructural effect of those newly emerging drugs on parotid and submandibular salivary glands and to demonstrate the differential expression of CXCL10 to make a cogent structural and molecular assessment of the relative tolerability of these drugs and the potential mechanisms of occurrence of dry mouth. METHODS: Fifty male Sprague Dawley rats were equally divided into five groups: Group I (control), Group II (oxybutynin-treated), Group III (trospium-treated), Group IV (darifenacin-treated) and Group V (solifenacin-treated). Histological and ultrastructural studies were performed on parotid and submandibular glands. Measurement of salivary flow, PCR analysis and immunohistochemical assessment of CXCL10 expression have been carried-out. RESULTS: Muscarinic receptor antagonists led to various histological, morphometric and ultrastructural changes together with diminished salivary secretion and up-regulation of CXCL10 expression with the mildest alterations observed with solifenacin. CONCLUSIONS: Solifenacin has shown the least adverse effects to salivary glands. CXCL10 is involved in degenerative changes of salivary glands induced by muscarinic antagonists.
