Effects of the start time of glycemic control on erectile function in streptozotocin-induced diabetic rats

Abstract

Introduction：Diabetes-induced erectile dysfunction (DMED) correlates with diabetes duration and glycemic control. Strict glycemic control can improve DMED to near-normal status. This study evaluated the effect of glycemic control start time on erectile function in streptozotocin-induced diabetic rats. Materials and Methods: Eight-week-old Sprague–Dawley rats were divided into normal controls (group C)

untreated diabetic rats (group DM)

and rats treated after 7 weeks (group 7W), and 10 weeks (group 10W) from DM. Streptozotocin was injected to induce diabetes. Treated diabetic rats received a timed daily injection of insulin. After 14 weeks of lab-controlled diabetes, erectile function was assessed by cavernous nerve stimulation. And an evaluation of histological and biochemical markers from corporal tissue was performed. Results: Group DM showed the ratio of intracavernosal pressure to mean arterial pressure significantly lower than groups C, 7W, and 10W (10W vs. DM, p< 0.001). Groups 7W and 10W responded similarly (p= 0.170, 20 Hz

p= 0.769, 10 Hz) but did not recover to group Cs level (group C vs. 7W, p< 0.001). The percentage of α-smooth muscle actin increased more with earlier start times, and group DMs percentages decreased significantly (group 10W vs. DM, p< 0.001). Apoptotic cell density recovered significantly only in group 7W, comparable with group C (group 7W vs. 10W, p= 0.020). Densitometry analysis showed molecular changes in cavernosal tissues. As start times became earlier, for all molecules (eNOS, Akt, MYPT1, and PECAM-1), treatment groups results neared those of group C. Conclusion: When diabetic treatment started earlier, diabetic rats recovered erectile function similar to controls, but not to normal levels. The level of glycemic control was expected to be more important than the start time of DM treatment.