Alzet mini osmotic pump 2004

Human recombinant insulin was systemically supplemented by subcutaneous implantation of osmotic pumps as previously described [17 (link)]. Briefly, 6 weeks after the first streptozotocin injection, diabetic mice were anesthetized with 3% isoflurane and implanted with an Alzet Mini-Osmotic Pump 2004 (Durect, Cupertino, CA, USA), which delivered human recombinant insulin (MilliporeSigma) at a rate of 58.4 pmol/min/kg. One day after implantation of the osmotic pumps, human C-peptide was systemically supplemented by subcutaneous implantation of K9-C-peptide depots as previously described [26 (link)]. Briefly, insulin-supplemented diabetic mice were subcutaneously injected into the nape of the neck two times for 4 weeks with 100 mg/kg K9-C-peptide or 83 mg/kg of K8 polypeptide, a negative control for the K9-C-peptide, in PBS. The K9-C-peptide and K8 polypeptide were prepared by inverse transition cycling as previously described [27 (link)]. Four weeks after the subcutaneous injections, sera and retinal, lung, and kidney tissues were obtained from the mice and analyzed. All animal experiments conformed to the Guide for the Care and Use of Laboratory Animals (National Institutes of Health; Bethesda, MD, USA) and were approved by the Institutional Animal Care and Use Ethics Committee of Kangwon National University (KW-201204–3).