Diabetic bladder dysfunction is a frequent complication of diabetes. Although many mouse models of diabetes now exist, there has been little systematic effort to characterize them for the timing of onset and severity of bladder dysfunction. We monitored metabolic status and tested bladder function by void spot assay and limited anesthetized cystometry in both male and female mice of three models of obesity and diabetes: a type 1 diabetes model (the Akita mouse) and two type 2 diabetes models [the diet-induced obese (DIO) model and the ob/ob mouse]. Akita mice had insulin pellets implanted subcutaneously every 3 mo to mimic poorly controlled type 1 diabetes in humans. Mice were hyperglycemic by 48 days after implants. Female mice exhibited no bladder dysfunction at any age up to 20 mo and gained weight normally. In contrast, by 7 mo, male Akita mice developed a profound polyuria and failed to show normal weight gain. There were no observable signs of bladder dysfunction in either sex. DIO mice on high/low-fat diets for 16 mo exhibited mild hyperglycemia in female mice (not in male mice), mild weight gain, and no evidence of bladder dysfunction. Ob/ob mice were followed for 8 mo and became extremely obese. Male and female mice were glucose intolerant, insulin intolerant, and hyperinsulinemic at 4 mo. By 8 mo, their metabolic status had improved but was still abnormal. Urine volume increased in male mice but not in female mice. Bladder dysfunction was observed in the spotting patterns of female mice at 4 and 6 mo of age, resolving by 8 mo. We conclude there are dramatic sex-related differences in lower urinary tract function in these models. Male Akita mice may be a good model for polyuria-related bladder remodeling, whereas female ob/ob mice may better mimic storage problems related to loss of outlet control in a setting of type 2 diabetes complicated by obesity.

Acute kidney injury (AKI) is common in hospitalized patients and is strongly correlated with increased morbidity, mortality, and prolonged hospitalization. However, signals that determine whether injured tissues following AKI will repair or fibrose and lead to chronic kidney disease (CKD) are not well defined. Numerous cytokines are activated at various times after injury and recruit inflammatory cells. Interleukin-8 (IL-8) is upregulated following activation of Gα12 by H 2 O 2 , a reactive oxygen species (ROS). Herein, we study this occurrence in vitro and in vivo. IL-8 was measured by ELISA in Gα12-silenced (si-Gα12) and inducible QLα12 (constitutively active Gα12) Madin-Darby Canine Kidney (QLα12-MDCK) cell lines after H 2 O 2 /catalase cell injury. QLα12-and si-Gα12 MDCK cells showed time-, agonist-and Gα12-dependent increases in IL-8 mRNA and protein. Gα12-silenced MDCK cells demonstrated lower IL-8 expression and blunted IL-8 increases. In transgenic mice (QLα12 γGTCre+ , proximal tubule Qα12 expression) ischemia reperfusion injury led to significant upregulation of CXCL-1 (IL-8 homologue) at 48 hours that was not observed in Gα12 knockout mice. Macrophages in renal cells from these mice were imaged by immunofluorescent microscopy and QLα12 γGTCre+ showed increased macrophage infiltration. We demonstrate that IL-8 is a critical link between H 2 O 2 stimulated Gα12 and renal injury. Gα12 activation led to increased IL-8 expression, a potent mediator of inflammation after injury. Future studies targeting Gα12 for inhibition after injury may blunt the IL-8 response and allow for organ recovery.