Bp 98a

B6 and ApoE4-KI mice were anesthetized with 170 mg/kg propofol (Provine % [w/v], Baxter, Gujarat, India) delivered via retro-orbital injection (Figure 1B). The induction dose of propofol was 50 mg/kg and to maintain general anesthesia, 10 mg/kg was injected six times (every 10 min). The onset of anesthesia was marked by a reduced righting reflex and loss of the pedal withdrawal reflex. After induction, the pedal withdrawal reflex was tested 5 min. The absence of a response to a noxious stimulation was determined by a negative toe pinch response. We noninvasively monitored the blood pressure of the tail artery (BP-98A; Softron, Tokyo, Japan) and oxygen saturation (SpO₂, percutaneous oxygen saturation). The body temperature was maintained at 37°C at all times. The total anesthesia duration was up to 2 h. After shaving the surgical site and sterilizing it with povidone-iodine solution, a median abdominal incision (approximately 1.5 cm) was made in the peritoneal cavity (Figure 1C), followed by insertion of a sterile probe and gentle manipulation of the viscera for 3 min (Figure 1D). Sterile 4–0 silk thread sutures were then used to close the peritoneal lining and the skin. All surgeries were performed by a single operator; each procedure required 10 min. After surgery, the mice were placed on heated pads and, after recovery, were returned to their cages (Figure 1E).

After four weeks of Lir administration, the blood pressure (BP) of conscious animals was recorded using the tail-cuff plethysmography (BP-98A, Softron Corporation, Beijing, China). The measurements were recorded in preheated chambers at 36–37°C for 10–15 min following the training sessions.
Using the Vevo 2100 system with an MS400 linear array transducer (VisualSonics, ON, Canada), the procedure of transthoracic echocardiography was performed on all mice. Briefly, mice were anesthetized using 2% isoflurane and kept warm using a heating pad (37°C). A depilatory cream was used to remove the chest hair, and a layer of acoustic coupling gel was applied to the thoracic region. RVFWT was measured from the parasternal short-axis view at the midpapillary level of the left ventricle. The pulmonary blood outflow was recorded by pulse-wave Doppler echocardiogram at the level of the aortic valve in the short axis view to measure the values of PAT, PET, and mPAP. Next, the LAD, the left ventricular ejection fraction (LVEF), and LVEDD were measured as described previously [20 (link)].