Open AccessA role for phosphodiesterase type 5 inhibitors in remodelling the urinary bladder after radiation exposure
Author(s) -
Hee Youn Kim,
Dong Sup Lee
Publication year - 2020
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0242006
Subject(s) - enos , endocrinology , medicine , protein kinase b , endothelial nos , angiogenesis , vascular endothelial growth factor , nitric oxide synthase , cystometry , cgmp specific phosphodiesterase type 5 , nitric oxide , sildenafil , chemistry , urinary system , signal transduction , biochemistry , vegf receptors
Minimizing the toxicity of radiotherapy is challenging. We investigated the effects of a phosphodiesterase type-5 inhibitor (PDE5I) on the urinary bladder after pelvic radiotherapy. Eight rats were assigned to each group (group 1: control; group 2: radiation; group 3: radiation plus PDE5I). Radiation dose was 10 Gy/one fraction. Udenafil (20 mg/kg, daily for 4 weeks) was administered in group 3. Cystometry was performed 4 weeks after treatment, followed by real-time PCR for PDE5, vascular endothelial growth factor (VEGF), and endothelial nitric oxide synthase (eNOS) mRNA, western blotting for PDE5, cyclic GMP-dependent protein kinase (PRKG), VEGF 164 , Akt, eNOS and NADPH oxidase (NOX)-2 proteins, and immunohistochemistry for eNOS. The expression of both VEGF mRNA and eNOS mRNA was higher in group 3 than in group 2. VEGF and eNOS protein expression improved with PDE5I treatment. Akt protein phosphorylation was higher in group 3 than in group 2, but NOX-2 protein expression was lower in group 3 than in group 2. Immunohistochemistry showed that the mean density of arterioles expressing eNOS was higher in group 3 than in group 2. Cystometry revealed that the intercontraction interval was remarkably longer in group 3 than in group 2 but that the maximal voiding pressure was higher in group 2 than in group 3. Daily treatment with a PDE5I after radiotherapy may prevent bladder storage dysfunction, potentially due to its effects on vasodilation and angiogenesis and through minimizing tissue oxidative damage by means of the VEGF/Akt/eNOS pathway.