Comparative anatomy of the male guinea-pig and human lower urinary tract: Histomorphology and three-dimensional reconstruction

The guinea-pig is often used for experimental studies: in urology. However, the anatomy of the lower urinary tract of the guinea-pig is poorly describ ed in the literature. The structure and function of the lower urinary tract , i.e. continence, micturition and sexual function, are closely related to the gross anatomy of the pelvis and the fine structure of the musculature. We investigated the anatomy and histomorphology of the lower urinary tract by serial sections in male guineapigs and compared it to that in humans. Im munohistochemical stainings for alpha-smooth muscle cell actin were used to differentiate between smooth and striated muscles. By using whole pelvic p reparations. including all internal organs preserved in their in situ locat ion for three-dimensional reconstruction, we dec eloped three-dimensional m odels, which elucidate the spatial relationship of all muscular structures and can help to deduce functional aspects of lower urinary tract function. In the guinea-pig, most of the muscles found in humans can be demonstrated in comparable location and extension. However, the structure of the prostat e and the existence of the so-called coagulation glands define a significan t difference in the morphology of the prostatic urethra.