Charles Drew University (CDU), Department of Internal Medicine, Los Angeles, CA, USA.
J Sex Med. 2010 Sep;7(9):3033-44. doi: 10.1111/j.1743-6109.2010.01884.x.
Endogenously elicited inducible nitric oxide synthase (iNOS) induction counteracts fibrosis and oxidative stress in penile tissues in rat models of Peyronie's disease and erectile dysfunction.
The current study aimed to determine whether the genetic blockade of iNOS expression in the iNOS knock out (iNOS KO) mouse intensifies fibrosis and oxidative stress in the penile corpora cavernosa, and this is exacerbated by streptozotocin (STZ)-induced diabetes and counteracted by insulin.
Quantitative assessment of histological and biochemical markers in mouse corporal tissue.
Male iNOS KO and wild type (WT) mice were left untreated or injected with STZ, with or without insulin treatment. At 8 weeks, glycemia, glucosuria, and proteinuria were determined, and corporal tissue sections were obtained and subjected to Masson trichrome staining for smooth muscle (SM)/collagen ratio, and immunostaining for α-smooth muscle actin (ASMA) for, SM content, proliferating cell nuclear antigen (PCNA) for cell replication, TGFβ1 as profibrotic factor, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay for apoptosis, and xanthine oxidoreductase (XOR) for oxidative stress. Collagen was estimated by the hydroxyproline reaction.
The corporal SM/collagen ratio and SM content were reduced, and collagen content increased in iNOS KO mice as compared with WT mice, but apoptosis was decreased and cell replication increased, whereas TGFβ1 and XOR did not vary. Severe hyperglycemia caused in the WT a reduction of the corporal SM/collagen ratio and SM content and an increase in apoptosis without changes in PCNA, TGFβ1, or XOR. In the iNOS KO mouse the hyperglycemia-induced alterations were exacerbated, with additional increases in oxidative stress and TGFβ1. Insulin normalized glycemia and partially protected the SM in both the WT and the iNOS KO mice.
The antifibrotic, antioxidative, and SM-protective roles of iNOS in the penile corpora cavernosa were confirmed in the iNOS KO/STZ mouse model. These findings support the importance of endogenously-elicited iNOS induction in protecting the penile corpora cavernosa from the pro-fibrotic effects of hyperglycemia.
内源性诱导型一氧化氮合酶（iNOS）的诱导可抵抗阴茎组织中的纤维化和氧化应激，这在佩罗尼氏病和勃起功能障碍的大鼠模型中得到了证实。
本研究旨在确定 iNOS 敲除（iNOS KO）小鼠中 iNOS 表达的遗传阻断是否会加剧阴茎海绵体组织的纤维化和氧化应激，而这种情况会因链脲佐菌素（STZ）诱导的糖尿病而加剧，并可以被胰岛素抵消。
对小鼠海绵体组织的组织学和生化标志物进行定量评估。
雄性 iNOS KO 和野生型（WT）小鼠未经处理或注射 STZ，同时或不进行胰岛素治疗。8 周后，测定血糖、尿糖和蛋白尿，并获取海绵体组织切片，进行 Masson 三色染色以评估平滑肌（SM）/胶原比，免疫染色以评估α-平滑肌肌动蛋白（ASMA）以评估 SM 含量，增殖细胞核抗原（PCNA）以评估细胞复制，转化生长因子β1（TGFβ1）作为促纤维化因子，末端脱氧核苷酸转移酶 dUTP 缺口末端标记（TUNEL）测定法评估细胞凋亡，黄嘌呤氧化还原酶（XOR）评估氧化应激。胶原通过羟脯氨酸反应进行估计。
与 WT 小鼠相比，iNOS KO 小鼠的海绵体 SM/胶原比和 SM 含量降低，胶原含量增加，但细胞凋亡减少，细胞复制增加，而 TGFβ1 和 XOR 没有变化。严重的高血糖导致 WT 小鼠海绵体 SM/胶原比和 SM 含量降低，细胞凋亡增加，但 PCNA、TGFβ1 或 XOR 没有变化。在 iNOS KO 小鼠中，高血糖诱导的改变加剧，同时氧化应激和 TGFβ1 增加。胰岛素使血糖正常化，并在 WT 和 iNOS KO 小鼠中部分保护 SM。
在 iNOS KO/STZ 小鼠模型中，证实了 iNOS 在阴茎海绵体中的抗纤维化、抗氧化和 SM 保护作用。这些发现支持内源性诱导型一氧化氮合酶诱导在保护阴茎海绵体免受高血糖致纤维化作用的重要性。
