Sulforaphane Ameliorates Bladder Dysfunction through Activation of the Nrf2-ARE Pathway in a Rat Model of Partial Bladder Outlet Obstruction

Abstract

Purpose. We evaluated the effect of sulforaphane (SFN) treatment on the function and changes of expression of Nrf2-ARE pathway in the bladder of rats with bladder outlet obstruction (BOO). Materials and Methods. A total of 18 male Sprague-Dawley rats at age of 8 weeks were divided into 3 groups (6 of each): the sham operated group, the BOO group, and the BOO+SFN group. We examined histological alterations and the changes of oxidative stress markers and the protein expression of the Nrf2-ARE pathway. Results. We found that SFN treatment could prolong micturition interval and increase bladder capacity and bladder compliance. However, the peak voiding pressure was lower than BOO group. SFN treatment can ameliorate the increase of collagen fibers induced by obstruction. SFN treatment also increased the activity of SOD, GSH-Px, and CAT compared to the other groups. The level of bladder cell apoptosis was decreased in BOO rats with SFN treatment. Moreover, SFN could reduce the ratio of Bax/Bcl-2 expression. Furthermore, SFN could activate the Nrf2 expression with elevation of its target antioxidant proteins. Conclusions. The sulforaphane-mediated decrease of oxidative stress and activation of the Nrf2-ARE pathway may ameliorate bladder dysfunction caused by bladder outlet obstruction.

Figure 1

Effect of SFN on urodynamic changes in conscious BOO rats.

Figure 2

Effect of SFN on bladder histological changes in BOO rats. Original magnification ×100. (a) HE staining in sham, BOO, and BOO+SFN bladders; (b) Masson trichrome staining in sham, BOO, and BOO+SFN bladders; (c) the percentage of collagen fibers in muscular layer in sham, BOO, and BOO+SFN bladders, ^∗ n = 6, P < 0.05 versus sham group, ^# n = 6, P < 0.05 versus BOO group.

Figure 3

Effects of SFN on attenuating oxidative stress in BOO rats. (a) MDA level in the bladder of the three groups, ^∗ n = 6, P < 0.05 versus sham group. ^# n = 6, P < 0.05 versus BOO group. (b) MDA level in serum of the three groups, ^∗ n = 5, P < 0.05 versus sham group. (c) The activity of total SOD in the bladder of the three groups, ^∗ n = 6, P < 0.05 versus sham group. ^# n = 6, P < 0.05 versus BOO group. (d) The activity of GSH-Px in the bladder of the three groups, ^∗ n = 6, P < 0.05 versus sham group. ^# n = 6, P < 0.05 versus BOO group. (e) The activity of CAT in the bladder of the three groups, ^∗ n = 6, P < 0.05 versus sham group.

Figure 4

Effect of SFN on cell apoptosis and proliferation in BOO rats. (a) TUNEL staining showing the cell apoptosis level of the bladder in the three groups. Original magnification ×400. (b) The protein expression of Bax/Bcl2 ratio in the bladder of the three groups. (c) The statistical results of TUNEL staining in the three groups. ^∗ n = 6, P < 0.001 versus sham group. ^# n = 6, P < 0.001 versus BOO group. (d) The statistical results of protein expression of Bax/Bcl2 ratio in the bladder of the three groups. ^∗ P < 0.05 versus sham group. ^# P < 0.05 versus BOO group. (e) The expression of PCNA by immunohistochemical staining in the three groups. Original magnification ×200.

Figure 5

Effect of SFN on the Nrf2-ARE pathway in BOO rats. (a) Immunohistochemical staining of Nrf2 and HO-1 in the bladder of the three groups. Original magnification ×200. (b) The protein expression of total Nrf2 in the bladder of the three groups. (c) The protein expression of nuclear Nrf2 in the bladder of the three groups. (d) The protein expression of HO-1 in the bladder of the three groups. (e) The protein expression of NQO1 in the bladder of the three groups. ^∗ P < 0.05 versus sham group. ^# P < 0.05 versus BOO group.