Integrated in vivo pharmacology using an instrumented, unrestrained and conscious rat platform: application to rat models of diabetes.

INTRODUCTION: We define the technical and methodological aspects that led to a practical and reproducible biological in vivo platform allowing the measurement of more than 65 physiobiochemical parameters on a daily basis in freely moving conscious animals. Such a platform presents the ability to unleash incremental information in the hands of modern-day pharmacologists and physiologists. METHODS: To validate this platform, we fully characterized three rat models of Type 1 and Type 2 diabetes and their respective controls. Control, streptozotocin- and alloxan-diabetic Wistar rats in addition to ZDF-Lean and ZDF-Fatty rats were chronically implanted with an arterial catheter and kept in metabolic cages. The catheter was connected to a minipump infusing saline at a constant rate to maintain patency and used to collect blood and measure hemodynamic parameters on a daily basis. RESULTS: Catheter implantation was successful in over 95% of animals and catheter patency was successfully maintained for 30 days in about 75% of animals. The three diabetic rat strains showed elevations in food and water consumption, urinary output, plasma glucose, blood urea nitrogen, triglycerides and cholesterol. The two Type I models also showed a depressed body weight and hemodynamic function. The STZ model differed from the alloxan-model by elevations in liver enzyme activities (AST, ALT, and bilirubin) and a more severe dyslipidemia (triglycerides and total cholesterol). The ZDF-Fatty rats distinguished themselves by higher body weight and elevated white blood cell counts. DISCUSSION: This integrated platform represents a significant improvement in standard in vivo evaluations and could greatly improve the pace of development of potential new drugs.

Inhibition of type 1 diabetic hyperalgesia in streptozotocin-induced Wistar versus spontaneous gene-prone BB/Worchester rats: efficacy of a selective bradykinin B1 receptor antagonist.

Insulin-dependent type 1 diabetes (T1D) is linked to a series of complications, including painful diabetic neuropathy (PDN). Several neurovascular systems are activated in T1D, including the inducible bradykinin (BK) B1 receptor (BKB1-R) subtype. We assessed and compared the efficacy profile of a selective BKB1-R antagonist on hyperalgesia in 2 models of T1D: streptozotocin (STZ) chemically induced diabetic Wistar rats and spontaneous BioBreeding/Worchester diabetic-prone (BB/Wor-DP) rats. Nociception was measured using the hot plate test to determine thermal hyperalgesia. STZ diabetic rats developed maximal hyperalgesia (35% decrease in their hot plate reaction time) within a week and remained in such condition and degree for up to 4 weeks postinjection. BB/Wor-DP rats also developed hyperalgesia over time that preceded hyperglycemia, starting at the age of 6 weeks (9% decrease in the hot plate reaction time) and stabilizing over the age of 16 to 24 weeks to a maximum (60% decrease in the hot plate reaction time). Single, acute subcutaneous administration of the selective BKB1-R antagonist induced significant time- and dose-dependent attenuation of hyperalgesia in both STZ diabetic and BB/Wor-DP rats. Thus, selective antagonism of the inducible BKB1-R subtype may constitute a novel and potential therapeutic approach for the treatment of PDN.