Department of Urology, Chonnam National University Medical School, Sexual Medicine Research Center, Chonnam National University, Gwangju, Korea.
Urology. 2012 Sep;80(3):737.e7-12. doi: 10.1016/j.urology.2012.03.026. Epub 2012 May 17.
To investigate the effect of hyperglycemia on the expression of the aquaporin (AQP) isoforms in the diabetic rat vagina.
Female Sprague-Dawley rats (230-240 g, n = 45) were divided into control (n = 10) and experimental (n = 35) groups. Diabetes in the experimental group was induced by intraperitoneal injection of streptozotocin (STZ, 65 mg/kg). STZ-induced diabetic rats were left untreated or given subcutaneous injections of insulin (3 U/d). After 2 and 4 weeks, the blood glucose was measured, and the vaginal blood flow was assessed by Doppler flowmetry. The expression and cellular localization of AQP1 and AQP2 in the rat vagina were determined by Western blot and immunohistochemistry.
The vaginal blood flow (mL/min/100 g tissue) after pelvic nerve stimulation was significantly lower in the STZ-induced diabetic rats (21.9 ± 6.5 at 2 weeks and 21 ± 2.8 at 4 weeks) compared with the control group (55.5 ± 8.9 at 2 weeks and 52.9 ± 6.5 at 4 weeks; P < .05). In contrast, the vaginal blood flow response was significantly greater in the insulin-treated diabetic groups (47.7 ± 8.7 at 2 weeks and 47.7 ± 8.4 at 4 weeks) and comparable to that of the control group. The protein expression of AQP2 was significantly lower in the STZ-induced diabetic rats and was restored to the control level after insulin treatment. However, no change was seen in AQP1 expression. Thus, hyperglycemia might cause downregulation of AQP2 expression in the diabetic rat vagina.
These results suggest that decreased vaginal lubrication in diabetic women might result from changes in aquaporin expression, in addition to a reduction in the vaginal blood flow response.
研究高血糖对糖尿病大鼠阴道水通道蛋白（AQP）亚型表达的影响。
将 45 只雌性 Sprague-Dawley 大鼠（230-240 g，n = 45）分为对照组（n = 10）和实验组（n = 35）。实验组大鼠腹腔注射链脲佐菌素（STZ，65 mg/kg）诱导糖尿病。未治疗 STZ 诱导的糖尿病大鼠或给予皮下注射胰岛素（3 U/d）。2 周和 4 周后，测量血糖，通过多普勒血流仪评估阴道血流。通过 Western blot 和免疫组织化学测定大鼠阴道 AQP1 和 AQP2 的表达和细胞定位。
与对照组相比（2 周时为 55.5 ± 8.9，4 周时为 52.9 ± 6.5），STZ 诱导的糖尿病大鼠（2 周时为 21.9 ± 6.5，4 周时为 21 ± 2.8）经阴部神经刺激后的阴道血流（mL/min/100 g 组织）明显降低（P <.05）。相比之下，胰岛素治疗的糖尿病组的阴道血流反应明显更大（2 周时为 47.7 ± 8.7，4 周时为 47.7 ± 8.4），与对照组相当。AQP2 蛋白表达在 STZ 诱导的糖尿病大鼠中明显降低，经胰岛素治疗后恢复至对照组水平。然而，AQP1 表达没有变化。因此，高血糖可能导致糖尿病大鼠阴道 AQP2 表达下调。
这些结果表明，除了阴道血流反应减少外，糖尿病女性阴道润滑减少可能是由于水通道蛋白表达的变化所致。
