Investigative urology

Sampaio, Francisco J.B.

doi:10.1590/S1677-55382003000600018

UROLOGICAL SURVEY

Investigative urology

Analysis of the modifications in the composition of bladder glycosaminoglycan and collagen as a consequence of changes in sex hormones associated with puberty or oophorectomy in female rats

Cabral CA, Sampaio FJ, Cardoso LE

Urogenital Research Unit, State University of Rio de Janeiro, Brazil

J Urol. 2003;170: 2512-6

PURPOSE: The effects of female sex hormones on rat vesical extracellular matrix were evaluated by analyzing glycosaminoglycan (GAG) and collagen composition under different hormonal conditions.

MATERIALS AND METHODS: Bladders were obtained from Wistar rats, including young prepubertal females at age 30 days (YF), and adult intact females (AF), adult oophorectomized females (AOF), adult males and adult sham operated females at age 120 days. Oophorectomy and sham operation were performed at age 30 days. Bladders were analyzed for total GAG and collagen concentration per mg dry tissue and for the contents of GAG species, as determined by agarose electrophoresis and reported as the percent of total sulfated GAG.

RESULTS: Collagen concentration in AF (54.80 +/- 4.60 microg/mg) was different from that in YF (34.52 +/- 5.29 microg/mg, p <0.001) and AOF (63.25 +/- 3.51 microg/mg, p <0.001). GAG concentration in AF (0.71 +/- 0.18 microg/mg) was different from that in YF (0.45 +/- 0.07 microg/mg, p <0.001) and males (0.46 +/- 0.10 microg/mg, p <0.001). The GAG species detected were dermatan sulfate and heparan sulfate. Dermatan sulfate content in AF (90.9% +/- 2.8%) was different from that in YF (86.6% +/- 2.4%, p <0.005), AOF (87.9% +/- 2.1%, p <0.005) and males (87.7% +/- 4.7%, p <0.005). Heparan sulfate content in AF was 9.1% +/- 2.8%, which differed from that in YF (13.4% +/- 2.4%, p <0.025) and AOF (11.2% +/- 2.9%, p <0.025).

CONCLUSIONS: Extracellular matrix of the female rat bladder undergoes marked remodeling during normal growth up to early adulthood with important consequences for vesical viscoelastic properties. Also, oophorectomy performed at a prepubertal age may lead to greater vesical wall stiffness.

Editorial Comment

Sex hormones have been shown to variously affect the synthesis of extracellular matrix (ECM) molecules by mesenchymal cells such as fibroblasts and smooth muscles cells, both in vivo and in vitro. This effect is exerted on several tissues and organs and has, in many cases, a normal regulatory role. The ECM may also undergo abnormal modifications, and these have been implicated with many diseases, including urinary tract disorders. In the present study, the effects of female sex hormones on the biochemical composition of vesical glycosaminoglycans (GAG) and collagen in rats under different hormonal conditions were evaluated.

The results show that variations in the plasma levels of female sex hormones parallel different changes in the ECM composition of the rat bladder wall. During the normal growth of the female rat from a pre-pubertal age to early adulthood, there are marked increases in both total GAG and collagen concentrations, together with a small increase in dermatan sulfate and a more important decrease in heparan sulfate. Compared to the intact adult females, the bladders from oophorectomized adult females had a slightly higher collagen concentration but presented no change in total GAG, whereas the dermatan sulfate and heparan sulfate contents were decreased and increased, respectively, which may lead to greater vesical wall stiffness. Bladders from adult males differ from those of females of comparable age in that they have less total GAG, and hence a higher collagen: GAG ratio, and slightly less dermatan sulfate. In conclusion, this work demonstrates that the ECM of the female rat bladder undergoes a marked remodeling during normal growth up, which can lead to important consequences for vesical viscoelastic properties.

Dr. Francisco J.B. Sampaio

Full-Professor and Chair, Urogenital Research Unit

State University of Rio de Janeiro

Rio de Janeiro, Brazil

Experimental varicocele induces testicular germ cell apoptosis in the rat

Barqawi A, Caruso A, Meacham RB

From the Division of Urology, Department of Surgery, University of Colorado School of Medicine, Denver, Colorado, USA

J Urol. 2004; 171: 501-3

PURPOSE: We evaluated the impact of experimentally created varicocele on ipsilateral and contralateral testicular germ cells in the rat.

MATERIALS AND METHODS: Experimental left varicocele was created by partial ligation of the left renal vein in 17 adult male Sprague-Dawley rats. An additional 5 rats that underwent laparotomy and renal vein handling without ligation served as sham surgical controls. Five rats that underwent no surgical or other intervention served as a control group. Rats were sacrificed 7 (5), 14 (5) or 28 (7) days following varicocele creation. Germ cell apoptosis was quantified using a TUNEL assay. The results of this assay are expressed as the number of apoptotic germ cell nuclei per seminiferous tubular cross section. The presence of apoptosis was confirmed by cellular ultrastructure evaluation using transmission electron microscopy.

RESULTS: Control and sham animals were found to have a mean of 0.05 and 0.15 apoptotic germ cells per seminiferous tubular cross section, respectively. Rats sacrificed 7, 14 and 28 days after varicocele creation were found to have 0.15, 0.23 and 0.27 apoptotic germ cells per tubule in the ipsilateral testis, and 0.14, 0.16 and 0.17 apoptotic germ cells per tubule in the contralateral testis, respectively. Compared with control animals a statistically significant increase in the number of apoptotic germ cells per tubular cross section was noted 14 days following varicocele creation in the ipsilateral testis (p < 0.05).

CONCLUSIONS: The creation of experimental varicocele generated an increase in germ cell apoptosis in the ipsilateral testis at 14 days compared with control animals.

Editorial Comment

Until now, a precise relationship between varicocele and infertility is yet to be clarified. The present study analyzed the testicular germ cell apoptosis in the rat as consequence of experimentally induced varicocele.

The authors used an established animal model for the creation of testicular varicocele for assessing the time impact of such a lesion on germ cell apoptosis. The findings confirmed that the normal Sprague-Dawley rat demonstrates low levels of germ cell apoptosis (0.05 apoptotic germ cells per tubular cross section). Also, the animals subjected to laparotomy without partial ligation of the renal vein demonstrated germ cell apoptosis that was not statistically different from that in normal controls. On the other hand, rats that underwent experimental varicocele creation showed significantly increased levels of germ cell apoptosis in the ipsilateral testis 14 days following varicocele creation.

Although the animal model of varicocele clearly differs from the clinical varicocele seen in humans, the findings of the present study indicate that experimental varicocele creation in the rat generates a time dependent increase in germ cell apoptosis in the ipsilateral testis. These findings may be the explanation of the mechanism by which varicocele exerts a pathological influence on testicular function in a clinical setting.