Nutri plus gel

Post-operative mortality is generally high in 6-OHDA mice models, and animals can suffer from a variety of complications (Table S3) [11 ,25 (link)]. However, this can be overcome by continuous health assessment and intensive post-operative care after lesion surgery. Thus, health status of each animal was assessed during the first 14 days post-surgery, and mice that reached the human endpoints [56 (link)] were euthanized. During the recovery, animals were housed in a warmed room and post-operative care was performed twice a day.
Following surgery, animals received 0.1 mg/kg injections of buprenorphine (i.p.) every 6 h for 5 days to avoid pain, and 5 mg/kg carprofen subcutaneously (s.c.) every 24 h for 3 days. Animals received 1 mL injections (s.c.) of sterile and warm saline twice daily to mitigate dehydration, and if needed, they were fed by hand with providing Nutri-plus Gel (Virbac, Nice, France) into the mouth via 1 mL syringe. Until the animals got used to the energy supplement, s.c. injections of 1 mg/kg/day Duphalyte (Zoetis, Parsippany-Troy Hills, NJ, USA) were also administered. Mice were weighed every day in the first week post-surgery, and then once a week until the end of the experiment (Figure S5). The mortality rate of mice in the 6-OHDA group was 25.7% (9 animals were lost during the experiment).

Stereotactic surgeries were conducted under isoflurane anesthesia (4% induction, 2% maintenance) following the description of Thiele et al. [43 (link)]. In brief, 6-OHDA (3 µg in 0.2 µl of 0.02% ascorbate-saline) was injected into the right MFB at the following coordinates relative to the bregma or the dural surface: A/P − 1.2 mm; L/M − 1.1 mm; D/V − 5.0 mm. Lidocaine, buprenorphine (0.1 mg/kg, s.c. once before surgery), and carprofen (5 mg/kg, s.c. once after surgery) were used for pain relief. Intensive postoperative care included warm saline injections to prevent dehydration, alleviating hypothermia with heating pads, food pellets softened by soaking in water, high-energy palatable diet (Bacon Softies, Bio-Serv, Flemington, NJ, USA; Nutriplus gel, Virbac, Carros, France), and feeding by hand. One animal out of 15 was euthanized due to a poor postoperative condition (postoperative mortality 7%).