目的：排尿障害を惹起する前立腺の組織学的な特徴を抽出し, 排尿障害との関連性を明らかにする.
対象：成熟齢（平均50. 0 ± 3. 7 週齢）のC57BL/6J 雄性マウス8 匹及び老齢（平均137. 3 ± 21.2 週齢）のC57BL/6J 雄性マウス28 匹を用いた.
方法：マウスの排尿量を経時的に測定し, 尿流測定パラメーター（1 回排尿量, 排尿持続時間, 平均排尿速度）を得た. 次に, 前立腺組織像を検鏡観察し上皮面積/ 腺管面積比及び上皮細胞密度（＝上皮細胞数/ 上皮面積比）を求めた.
結果：老齢マウス28 匹のうち, 成熟齢マウスと同様な尿流測定パラメーターを呈した22 匹を老齢正常群（平均134. 3 ± 19. 7 週齢）とし, 点状の排尿瘢痕がみられた6 匹を排尿障害群（平均148. 3 ± 24. 8 週齢）とした. 排尿障害群は老齢正常群と比較して1 回排尿量と排尿持続時間が有意に低下し,背葉前立腺組織の上皮細胞密度が有意に増加した.
結論：背葉前立腺の上皮細胞密度の増加によって排尿障害が惹起されることが示唆された.

Objective: The purpose of this study was to elucidate the histological characteristics of the prostate with induced dysuria in mice and to clarify the relationship with dysuria.
Materials and Methods: Eight adult male C57BL/6J mice (mean age ± SD = 50.5 ± 3.7 wk) and 28 aged male C57BL/6J mice (mean age ± SD = 137.3 ± 21.2 wk) were used. Three uroflow parameters—voiding time, voided volume, and average flow rate—were determined in all mice from the uroflow curves. All the mice were sacrificed after 　the uroflowmetry examination to obtain the prostate specimen. The histologic examination of the prostate specimens was performed to evaluate prostatic hyperplasia. Epithelial area/gland area and epithelial cell density (= number of epithelial cells / epithelial area) were calculated for each gland.
Results: The 28 aged male C57BL/6J mice were divided into two groups by uroflow profile: normal group (n = 22) and abnormal group (n = 6). A relationship between uroflow parameters and epithelial cell density in the gland was surveyed. In the dorsal lobe of the prostate, the epithelial cell density of the abnormal group was significantly higher than that of the normal group. We observed a significant negative correlation between epithelial cell density and uroflow parameters (voided volume and voiding time).
Conclusions: We elucidated an inverse correlation between uroflow parameters (voided volume and voiding time) and epithelial cell density of the prostate. These results indicate that dysuria would be caused by epithelial cell hyperplasia of the dorsal lobe of the prostate.