Validation of Fenoterol to Study β2-Adrenoceptor Function in the Rat Urinary Bladder

Fenoterol is a β₂-adrenoceptor (AR)-selective agonist that is commonly used to investigate relaxation responses mediated by β₂-AR in smooth muscle preparations. Some data have questioned this because fenoterol had low potency in the rat urinary bladder when a muscarinic agonist was used as a pre-contraction agent and because some investigators proposed that fenoterol may act in part via β₃-AR. We designed the present study to investigate whether fenoterol is a proper pharmacological tool to study β₂-AR-mediated relaxation responses in the rat urinary bladder. Firstly, we have compared the effect of pre-contraction agents on fenoterol potency and found that fenoterol potency was about 1.5 log units greater against KCl than carbachol (pEC₅₀ 7.19 ± 0.66 and 5.62 ± 1.09 of KCl and of carbachol, respectively). To test the selectivity of fenoterol, we have determined the effects of the β₂-AR antagonist ICI 118,551 and the β₃-AR antagonist L 748,337 on relaxation responses to fenoterol. While 300 nM L 748,337 had little effect on the potency of fenoterol (pEC₅₀ 6.56 ± 0.25 and 6.33 ± 0.61 in the absence and presence of L 748,337, respectively), the relaxation curve for fenoterol was right-shifted in the presence 300 nM ICI 118,551 (pEC₅₀ 5.03 ± 0.18). Thus, we conclude that fenoterol is a proper pharmacological tool to assess β₂-AR-mediated responses in the rat urinary bladder and most likely in other smooth-muscle preparations containing multiple subtypes of the β-AR.

Experimental long-term diabetes mellitus alters the transcriptome and biomechanical properties of the rat urinary bladder

Diabetes mellitus (DM) is the leading cause of chronic kidney disease and diabetic nephropathy is widely studied. In contrast, the pathobiology of diabetic urinary bladder disease is less understood despite dysfunctional voiding being common in DM. We hypothesised that diabetic cystopathy has a characteristic molecular signature. We therefore studied bladders of hyperglycaemic and polyuric rats with streptozotocin (STZ)-induced DM. Sixteen weeks after induction of DM, as assessed by RNA arrays, wide-ranging changes of gene expression occurred in DM bladders over and above those induced in bladders of non-hyperglycaemic rats with sucrose-induced polyuria. The altered transcripts included those coding for extracellular matrix regulators and neural molecules. Changes in key genes deregulated in DM rat bladders were also detected in db/db mouse bladders. In DM rat bladders there was reduced birefringent collagen between detrusor muscle bundles, and atomic force microscopy showed a significant reduction in tissue stiffness; neither change was found in bladders of sucrose-treated rats. Thus, altered extracellular matrix with reduced tissue rigidity may contribute to voiding dysfunction in people with long-term DM. These results serve as an informative stepping stone towards understanding the complex pathobiology of diabetic cystopathy.

Morphological Peculiarities of Parasitic (Trichosomoides crassicauda) Infection in Rat Urinary Bladder

Trichosomoides crassicauda (T. crassicauda) is a parasite commonly localized in the urinary bladder (UB) of laboratory and wild rats. The presence of these helminths can influence the prediction of pathological changes in the UB. Therefore, the purpose of this research was to make a comprehensive study of the features of the morphological changes in the UB wall of white laboratory rats as a result of T. crassicauda infestation. The study was performed on male rats using histological (Hematoxyline-Eosin and Alcian Blue staining) and immunohistochemical (Ki-67, Hsp70, Hsp90α, CD3 and CD20) methods. T. crassicauda was detected in both urine and UB samples. Morphological changes were observed as disruption in urothelial cell stratification and insignificant proliferative and immune responses in the UB. Increased heat shock protein levels were observed which may suggest a natural body’s resistance to this parasite.

Acute effect of cyclophosphamide on rat’s urinary bladder and the possible protective role of sulforaphane: a histological and ultrastructural study

<p><strong>Background:</strong> Cyclophosphamide disturbs the oxidant and antioxidant balance that is associated with several unwanted toxic effects and induction of secondary cancers. The aim of this study was to test the protective effects of Sulforaphane on the cyclophosphamide toxicity of rat urinary bladder.</p><p><strong>Methods:</strong> 32 male albino rats were divided into 4 groups, 8 animal each (n=8). Group I received saline intra-peritoneal, group II received 5 mg/kg sulforaphane for 5 days and then saline, group III received 0.9% saline intra-peritoneal for consecutive 5 days and a single dose of cyclophosphamide 200 mg/kg on the six-day, group IV received sulforaphane at a dose of 5 mg/kg for consecutive 5 days and a single dose of cyclophosphamide 200 mg/kg on the six day. On the seventh day of the experiment, the animals were sacrificed, and the urinary bladder samples were dissected for histopathological and immunohistochemical investigations and electron microscopic studies.</p><p><strong>Results</strong>: the mucosa of the urinary bladder of Sulforaphane treated group showed normal architecture while that of cyclophosphamides treated group showed features of degenerated and ulcerated lesions of the epithelial lining associated with hemorrhage. Theses lesions markedly decreased in the mucosa of urinary bladder of cyclophosphamides and sulforaphane treated group.</p><p><strong>Conclusions</strong>: The use of sulforaphane reduces the cyclophosphamide toxicity on the urinary bladder in the form of decreased vacuolation with decreased degeneration of the epithelial lining.</p>

Effects of P-MAPA as Immunomodulator on Markers for Energy Metabolism in Bladder Cancer

Introduction This study characterized and compared cellular energetic metabolism features in the treatment of chemically induced non-muscle invasive bladder cancer (NMIBC) in Fischer 344 rats that were submitted to intravesical immunotherapies with P-MAPA (Protein aggregate magnesium-ammonium phospholinoleate-palmitoleate anhydride) and Bacillus Calmette-Guérin (BCG). Methods Rat urinary bladder samples from Control, NMIBC (Cancer), NMIBC+BCG and NMIBC+P-MAPA groups were submitted to histopathological and western blotting analyses for the following proteins: GLUT 1, PFK, GAPDH, HADHSC, β-F1-ATPase, AMPK and mTOR. Results P-MAPA Intravesical treatment was effective in tumor regression and histologic recovery of the urinary bladder in the NMIBC. There was a significant increase in protein levels of GLUT 1, mTOR, GAPDH and HADHSC in the NMIBC+P-MAPA group. It was observed an increase in protein levels of PFK and β-F1-ATPase and a significant reduction in protein levels of AMPk in the NMIBC group. Conclusions Our results showed that immunotherapy with P-MAPA may be an alternative in the treatment of NMIBC, especially in cases where BCG therapy failure, as evidenced by the effect of P-MAPA on tumor regression.