科研之友
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摘要
Diabetes is manifested predominantly in males in experimental models, and compelling evidence suggests that 17 beta-estradiol (E2) supplementation improves hyperglycemia in humans. We previously generated a severely diabetic transgenic (Tg) mouse model by beta-cell-specific overexpression of inducible cAMP early repressor (ICER) and found that male but not female ICER-Tg mice exhibit sustained hyperglycemia and develop major clinical and pathologic features of human diabetic nephropathy (DN). Thus, we hypothesized that differences in circulating hormone levels have a key role in determining susceptibility to diabetes. Here, we examined whether DN in male ICER-Tg mice is rescued by adjusting the androgen-to-E2 ratio to approximate that in normoglycemic female ICER-Tg mice. We treated hyperglycemic male ICER-Tg mice with orchiectomy (ORX), E2 pellet implantation, or both. E2 pellet implantation at an early stage of DN with or without ORX caused a rapid drop in blood glucose and a dramatic increase in beta-cell number, and it markedly inhibited DN progression [namely, E2 reduced glomerulosclerosis, collagen 4 deposition, albuminuria, and normalized prevented hyperfiltration). Furthermore, E2 pellet implantation was more effective than ORX alone and induced a remarkable improvement, even when initiated at advanced-stage DN. In contrast, induction of nornnoglycemia by islet transplant in ICER-Tg mice eliminated albuminuria but did not improve glomerulosclerosis or collagen 4 deposition or increased creatinine clearance. These findings indicate that E2 treatment is effective, even after establishment of DN, whereas glucose normalization alone does not improve sclerotic lesions. We propose that E2 intervention is a potential therapeutic option for DN.
- 出版日期2016-10
