The ethanol extract of the inner bark of Caesalpinia pyramidalis (Tul.) reduces urinary bladder damage during cyclophosphamide-induced cystitis in rats

Abstract

Hemorrhagic cystitis (HC) is a common side effect of cyclophosphamide therapy, which deserves new therapeutic strategies, such as those based on natural products. The ethanol extract of the inner bark of Caesalpinia pyramidalis (Tul.) (EECp) possesses anti-inflammatory, antinociceptive, and antioxidant activities as previously showed by our group. We have investigated the effect of EECp on the cyclophosphamide-induced HC. Cystitis was induced in male Wistar rats by the injection of cyclophosphamide. These animals were pretreated with EECp (100-400 mg/kg), vehicle, or mesna. Myeloperoxidase activity and malondialdehyde formation were measured in urinary bladder and other tissues. Bladder edema and histopathological alterations and serum nitric oxide metabolites concentration NOx- were also evaluated. Treatment with EECp (100-400 mg/kg) or mesna impaired the increase of myeloperoxidase activity in urinary bladder and the serum NOx- induced by cyclophosphamide but did not reduce edema in this tissue, as did mesna. Total histological score was reduced by EECp (100 mg/kg). Lung myeloperoxidase activity, which was increased by cyclophosphamide, was decreased significantly by EECp (400 mg/kg). EECp also diminished the malondialdehyde formation in bladder, lung, and spleen, although these parameters were not affected by cyclophosphamide. These results indicate that EECp reduced urinary bladder damage during cyclophosphamide-induced HC in rats.

Figure 1

The ethanol extract of Caesalpinia pyramidalis (EECp) decreases the myeloperoxidase (MPO) activity in bladder of rats during cyclophosphamide-induced cystitis. Animals were treated with EECp (100–400 mg/kg, p.o.), vehicle, or mesna (40 mg/kg, i.p.) and injected with cyclophosphamide (200 mg/kg, i.p.). After 24 h, the MPO activity was determined in urinary bladder homogenate and was expressed as units (U) of MPO/mg of tissue. ^### P < 0.001 versus vehicle + saline; *P < 0.05 or ***P < 0.001 versus vehicle + cyclophosphamide.

Figure 2

Urinary bladder weight of rats with cyclophosphamide-induced cystitis submitted to treatment with the ethanol extract of Caesalpinia pyramidalis (EECp). Animals were treated with EECp (100–400 mg/kg, p.o.), vehicle, or mesna (40 mg/kg, i.p.) and injected with cyclophosphamide (200 mg/kg, i.p.). After 24 h, the urinary bladder weight was measured and expressed as mg/g of whole body weight of animals. ^## P < 0.01 versus vehicle + saline; *P < 0.05 versus vehicle + cyclophosphamide.

Figure 3

Light microscopy of the bladders of rats with cystitis. Original magnification of 10-fold (Panels (a), (c), (e), (g), and (i)) or 40-(Panels (b), (d), (f), (h), and (j)); hematoxylin and eosin staining. Panels (a) and (b) show control saline + vehicle rats with normal tissue histology. Panels (c) and (d) demonstrate that injection of cyclophosphamide induced mucosal erosion and ulceration, severe edema in the submucosal region (∗), hemorrhagic foci (red arrows), and leukocyte infiltration (black arrows). Panels (e) and (f) indicate that EECp, at 100 mg/kg, reduced the cyclophosphamide-induced morphological alterations, affecting mainly the leukocyte infiltration and mucosal erosion/ulceration, which was not so clearly observed in the urinary bladders of EECp (400 mg/kg)-pretreated rats (Panels (g) and (h)) that still presented mucosal erosion, ulceration, edema in the submucosal region, and hemorrhagic foci. A slight leukocyte infiltration reduction was observed in these animals ((g) and (h)) when compared with animals pretreated with vehicle and injected with cyclophosphamide ((c) and (d)). Panels (i) and (j) show that mesna pretreatment almost completely reverted the damage induced by cyclophosphamide.