Chronic TGF-β2 Infusion in Diabetic Mice

After 1 week of acclimatization, two mice were placed into each cage, to avoid social isolation, and cage-mates were not changed during the experiment. Chronic TGF-β2 infusion was performed as previously described (Takahashi et al., 2019 (link)). Briefly, the animals were randomly allocated to three groups at 10 weeks of age: WT + vehicle; db/db + vehicle, and db/db + TGF-β2 groups. Under isoflurane anesthesia (induction: 4%, maintenance: 2%), the mice underwent surgery to implant Alzet mini-osmotic pumps (model 1002, Durect, Cupertino, CA, United States) subcutaneously. The osmotic pumps were filled with recombinant TGF-β2 (8406LC, Cell Signaling Technologies, Danvers, MA, United States) diluted in PBS, or PBS alone for the WT + vehicle and db/db + vehicle groups. For 12 consecutive days, the mice received 12 ng TGF-β2 each per hour. After euthanasia, the pumps were removed and the contents were confirmed to have been completely discharged. The dose and duration of treatment were those used in a previous study (Takahashi et al., 2019 (link)).