Bleomycin induced urethral stricture in Hodgkin's disease

An Experimental Model of Anterior Urethral Stricture in Rabbits With Local Injections of Bleomycin

OBJECTIVE

To develop an experimental model of anterior urethral stricture in rabbits using a bleomycin (BLM) injection technique.

MATERIALS AND METHODS

Thirty adult male New Zealand rabbits were randomly divided into 4 groups. In group 1 (BLM group), BLM was injected into the urethral submucosal tissue every other day through a catheter for 6 weeks at the 3-, 6-, 9-, and 12-o'clock positions of the urethra in 12 rabbits. In group 2 (phosphate-buffered saline [PBS] group), PBS was injected instead of BLM in 6 rabbits. In group 3 (stricture control group), an 8 × 20 mm urethral defect was created in 6 rabbits. In group 4 (normal group), 6 normal rabbits were included. All rabbits in the PBS group and stricture control group, as well as 6 rabbits in the BLM group, were sacrificed at 6 weeks. The remaining 6 rabbits in the BLM group were sacrificed at 10 weeks. Urethrography was performed in all rabbits before sacrifice, and the urethra was harvested for histologic analysis.

RESULTS

All rabbits in the BLM group showed mild urethral stricture at 4 weeks and significant urethral stricture at 6 weeks, without spontaneous resolution of the stricture at 10 weeks. No urethral stricture was observed in the PBS group at 4 and 6 weeks. Histologic examination confirmed the presence of fibrosis in the BLM group without spontaneous improvement.

CONCLUSION

BLM injection can induce an experimental model of anterior urethral stricture in rabbits. This simple, highly efficient, reproducible method can be carried out in any laboratory.

Effect of early treatment with transcutaneous electrical diaphragmatic stimulation (TEDS) on pulmonary inflammation induced by bleomycin

Background

Bleomycin (B) is an antineoplastic drug that has pulmonary fibrosis as a side effect. There are few experimental studies about the effects of physical therapy treatment in this case.

Objective

The objective was to study rat lungs treated with B and precocious intervention by transcutaneous electrical diaphragmatic stimulation (TEDS).

Method

Wistar rats were divided into 4 groups (n=5): a control group (C); a stimulated group (TEDS); a group treated with a single dose of B (intratracheally, 2.5 mg/kg) (B); and a group treated with B and electric stimulation (B + TEDS). After the B instillation, the electrical stimulation was applied for 7 days, for a duration of 20 minutes. Lung fragments were histologically processed with hematoxylin and eosin (HE) and 8-isoprostane-PGF2α (8-iso-PGF2α). The density of the alveolar area was determined by planimetry, the inflammatory profile was defined by the number of cells, and the level of oxidative stress in the pulmonary tissue was evaluated by 8-iso-PGF2α. For statistical analysis of the data, the Shapiro-Wilk test was used, followed by a one-way ANOVA with the post-hoc Bonferroni test (p≤0.05).

Results

The B group exhibited a significant reduction in the area density, and the acute treatment with B + TEDS prevented this reduction. There were increased numbers of fibroblasts, leukocytes, and macrophages in the B group, as well as increased lipid peroxidation, which was observed only in this group.

Conclusion

B promoted a reduction in the alveolar density area, thereby inducing the inflammatory process and increasing the production of free radicals. These effects were minimized by the application of TEDS at the initial treatment stage.