Colchicine and Phenylephrine Treatment in Mice

For chronic colchicine treatment of mice, 8–12-week-old male C57BL/6 wild-type mice were randomly assigned to vehicle, colchicine, PE, and colchicine/PE treatment groups. colchicine treatment followed a modified protocol from refs. ^{10 (link)} and ^{36 (link)}. Briefly, mice were I.P. injected every other day with colchicine in increasing doses (0.5, 0.75, and 1 mg/kg body weight) to improve tolerance^{9 (link)} and were maintained at the 1 mg/kg BW dose. Control animals were I.P. injected with PBS. PE (10 mg/kg BW in 0.2% ascorbic acid (Sigma-Aldrich) dissolved in PBS) was administered subcutaneously ~0.5–1 h after colchicine treatment (to ensure sufficient colchicine accumulation in the myocardium at the time of PE action²⁰ ) for 3 total injections over 5 days. Control animals received subcutaneous injections of vehicle (0.2% ascorbic acid in PBS). Mice showed no overt signs of distress or toxicity during this protocol, and on day 9 were euthanized for tissue harvesting. For acute colchicine treatment of rats, rats were injected I.P. with 1 mg/kg body weight sterile colchicine (Sigma-Aldrich) dissolved in PBS. The animals were euthanized 16–20 h after injection with colchicine.