Impact of prostatic radiation therapy on bladder contractility and innervation

Abstract

Aims: To determine the effect of prostatic radiation therapy (RT) on bladder contractility and morphology, and axon, or neuron profiles within the detrusor and major pelvic ganglia (MPG) in male rats. Methods: Male Sprague-Dawley rats (8 weeks) received a single dose of prostatic RT (0 or 22 Gy). Bladders and MPG were collected 2-and 10-weeks post-RT. Detrusor contractile responses to carbachol and electrical field stimulation (EFS) were measured. Bladders were stained with Masson's trichrome, and antibodies for nonspecific neuronal marker, cholinergic nerve marker choline acetyltransferase (ChAT), and alpha-smooth muscle actin.MPG gene expression was assessed by quantitative polymerase chain reaction for ubiquitin carboxy-terminal hydrolase L1 (Uchl1) and Chat. Results: At 2 weeks post-RT, bladder smooth muscle, detrusor cholinergic axon profiles, and MPG Chat gene expression were increased (p < .05), while carbachol and EFS-mediated contractions were decreased (p < .05). In contrast, at 10 weeks post-RT, nerve-mediated contractions were increased compared with control (p < .05), while bladder smooth muscle, detrusor cholinergic axon profiles, MPG Chat expression, and carbachol contractions had normalized. At both 2-and 10-weeks post-RT, there was no change in detrusor nonspecific axon profiles and MPG Uchl1 expression. Conclusion:In a rat model, RT of the prostate and MPG was associated with early changes in MPG Chat gene expression, and bladder cholinergic axon profiles and smooth muscle content which resolved over time. After RT recovery, bladder contractility decreased early and increased by 10 weeks. Longterm changes to the MPG and increased bladder cholinergic axons may contribute to RT-induced bladder dysfunction in prostate cancer survivors.

Effects of Microbeam Irradiation on Rodent Esophageal Smooth Muscle Contraction

“…The same could apply in our preparations since the CCH-induced maximal contraction strength was preserved, but the peak latency and maximal force change were significantly impaired. In contrast, the recent study by Turner et al [45] reported a KCl-induced decreased contraction of the bladder following irradiation of the rat prostate, and it was speculated that irradiation might also affect the smooth muscle itself. This highlights that the mechanisms of radiogenic injury to muscle remain poorly characterized.…”

“…This may indicate that MBI interfered with the signal transduction cascades of the contraction rather than the contractile apparatus itself, which would agree with the observations made in the current study on the esophagus. Similar physiologic studies were conducted with a rat urinary bladder [43][44][45] or with a human anal sphincter [46] using a conventional linear accelerator. Giglio et al [43] found that the methacholine and the electrical-field-stimulation (EFS) induced contractions were reduced after irradiation, whereas the contraction in response to potassium chloride (KCl) was not altered.…”

Recurrent infections drive persistent bladder dysfunction and pain via sensory nerve sprouting and mast cell activity

“…S1, I and J). To rule out persistent inflammation or altered detrusor function as alternative underlying causes of pain-like behavior and urinary frequency (47)(48)(49)(50), bladders were harvested from rUTI mice and assessed for immune infiltration by histology and flow cytometry (fig. S1, K to R) or detrusor function by muscle contractility assays (fig.…”