瘦素在糖尿病勃起功能障碍大鼠的血清表达及其与阴茎勃起功能的关系

The relationships between the level of serum leptin with the penile erectile functions in the diabetic rats with erectile dysfunction

目的探讨糖尿病性勃起功能障碍（DMED）大鼠血清瘦素（Leptin）表达水平及其与勃起功能的关系。方法将大鼠分为3组：对照组（A组）20只，糖尿病组（B组）20只，DMED组（C组）20只。取成年雄性SD大鼠80只，随机取20只为正常对照组，余下60只大鼠用于制作糖尿病（DM）模型，采用腹腔注射链脲佐菌素（STZ，60mg／kg）的方法，52只大鼠成模。行阴茎勃起功能实验筛选出伴性勃起功能障碍（ED）的糖尿病大鼠20只，为DMED组。另取20只未出现ED的糖尿病大鼠为DM组。3组大鼠麻醉后下腔静脉取血，放射免疫法测定血清中Leptin及睾酮水平；取阴茎组织用于免疫组织化学及反转录-聚合酶链反应（1it—PCR）。结果大鼠血清Leptin水平在DMED组（[6．13-t-O．07）nmol／L]较正常对照组[（1．99±0．08）nmol／L]显著升高（P〈0．05），而睾酮水平在DMED组[（255．55±5．62）nmol／L]较正常对照组[（2158．20±25．61）nmol／L]显著降低（P〈0．05）。两者呈显著负相关（Y=-479．89x±2991．7，r=-0．96，P〈0．01）。Leptin及其受体（OB—RL）的mRNA及蛋白表达水平在DMED组（0．96±0．12、0．95±0．09、4．36±0．52）较对照组（0．66±0．05、0．63±0．09、1．37±0．06）显著升高（P〈0．05）。结论血清Leptin水平升高可能是DMED发生的机制之一。

Objective To investigate the relationships between the level of serum leptin with the penile erectile functions in the diabetic rats with erectile dysfunction. Methods Rats were randomly divid- ed into 3 groups ： control group （ group A, n = 20 ）, diabetes mellitus （ DM ） group （ group B, n = 20 ）, and diabetic erectile dysfunction （DMED） group （group C, n = 20）. In 80 adult male SD rats, 20 rats were randomly selected as control group, and the rest rats were used for establishing DM models by intrap- eritoneal injection of chain urea with cephalosporins （STZ, 60 mg/kg）. Twenty diabetic rats with erectile dysfunction （ED） were selected by penile erectile function experiment as DMED group. Twenty diabetic rats without ED served as DM group. The blood samples were obtained via the inferior vena cava after anes- thesia. Serum leptin and testosterone levels were determined by radioimmunoassay. The penile tissue was taken out for immunohistochemistry and reverse transcriptase - polymerase chain reaction （ RT - PCR ）. Results The serum leptin level was increased significantly in DMED group [ （6. 13 ± 0. 07） nmol/L] as compared with control group [ （ 1.99±0. 08） nmol/L], but the testosterone level decreased significantly in DMED group [ （255.55 ±5.62） nmol/L] as compared with control group [ （2 158.20 ±25.61 ） nmol/L] （P 〈 0. 05 ）. Both had a significantly negative correlation （y = -479. 89x ± 2 991.7, r = 0. 96, P 〈 0. 01 ）. Leptin and its receptor mRNA expression of the OB - RL and immnnohistochemical expression level in DMED group （0. 96 ±0. 12, 0. 95±0. 09, and 4. 36 ± 0. 52） were significantly higher than in control group （0.66±0.05, 0.63 ±0.09, and 1.37 ±0.06） （P〈0.05）. Conclusion The increased serum leptin may be one of the mechanisms of diabetic erectile dysfunction.