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Updated: Jun 16, 2026
En Face Detection of Nitric Oxide and Superoxide in Endothelial Layer of Intact Arteries
Published on: February 25, 2016
[Expressions of NOS isoforms in the cavernous tissues of diabetic rat models]
Le-shen Yao1, Yang-tian Wang, Yun Chen
1Department of Urology, Drum Tower Hospital Affiliated to Nanjing University School of Medicine, Nanjing, Jiangsu 210008, China. yls7366@163.com
Objective:
To investigate the mechanism of diabetic erectile dysfunction (ED) and find new methods for its treatment by detecting the changes in nitric oxide synthase (NOS) isoforms and erectile function of diabetic rats and observing the effects of insulin and alpha-lipoic acid (LA) on it.
Methods:
Fifty male Sprague-Dawley rats were divided into Groups A (normal control, n=10), B (non-intervention diabetes mellitus, n=13), C (insulin intervention diabetes mellitus, n=12), and D (insulin + LA intervention, n=15). And the diabetic models were made by intraperitoneal injection of streptozocin (STZ). Eight weeks later, the erectile function of the rats was assessed following apomorphine injection and the contents of NOS isoforms in the erectile tissues measured by immunohistochemical staining.
Results:
All the rats of Group A showed a normal erectile function (100%). In comparison, those in Groups B, C and D exhibited a significantly decreased rate, 28.6% in Group B, 62.5% in Group C and 80.9% in Group D. The numbers of positive nNOS fibers and eNOS in the penile tissues per visual field were 86.7 and 9.6 in Group A, but only 36.5 and 3.3 in Group B, 52.7 and 5.7 in Group C, and 71.4 and 7.4 in Group D (P < 0.05). However, the expression of iNOS was significantly lower in Group A (6.9) than in Groups B (43.6), C (36.2) and D (19.3) (P < 0.05). Compared with Groups B and C, the erectile function and the expressions of nNOS and eNOS were markedly increased, while the expression of iNOS significantly decreased in Group D (P < 0.05).
Conclusion:
Diabetes mellitus severely affects penile erectile function and the expressions of NOS isoforms in the cavernous tissues, for which hyperglycemia is mainly responsible. LA is proved obviously efficacious for diabetic ED, which might be related to its antioxidant effect.
Insights
Diabetic erectile dysfunction (ED) impairs nitric oxide synthase (NOS) function. Alpha-lipoic acid (LA) combined with insulin effectively improves erectile function and NOS levels in diabetic rats.
Area of Science:
- Endocrinology and Metabolism
- Urology
- Biochemistry
Context:
- Diabetes mellitus is a complex metabolic disorder with significant microvascular and macrovascular complications.
- Erectile dysfunction (ED) is a common complication of diabetes, affecting a large proportion of affected individuals.
- The underlying mechanisms of diabetic ED involve endothelial dysfunction and alterations in nitric oxide synthase (NOS) pathways.
Purpose:
- To investigate the impact of diabetes on erectile function and NOS isoform expression in rat penile tissues.
- To evaluate the therapeutic efficacy of insulin and alpha-lipoic acid (LA) in ameliorating diabetic ED.
- To elucidate the potential mechanisms by which LA exerts its protective effects.
Summary:
- Diabetic rats exhibited significantly reduced erectile function and altered expression of neuronal NOS (nNOS) and endothelial NOS (eNOS), with increased inducible NOS (iNOS) compared to controls.
- Insulin treatment partially restored erectile function and NOS isoform balance.
- Combination therapy with insulin and LA demonstrated the most significant improvement in erectile function and normalization of NOS expression, alongside a reduction in iNOS.
Impact:
- This study highlights the critical role of hyperglycemia in driving diabetic ED through modulation of NOS pathways.
- Alpha-lipoic acid emerges as a promising therapeutic agent for diabetic ED, potentially through its antioxidant properties.
- Findings provide a mechanistic basis for developing novel therapeutic strategies targeting NOS pathways in diabetic complications.
