Previously, we introduced application examples of the macrophage depletion agent (Clodronate Liposomes) in different tissues of mice. Today, we will share relevant articles and methods for using Clodronate Liposomes in rats.
Consistent with its use in mice, the depletion principle in rats is as follows: Clodronate is encapsulated within the aqueous phase of phospholipids to form clodronate liposomes. Since clodronate cannot freely pass through the phospholipid bilayer, once injected into the organism, the liposomes are phagocytosed by macrophages. Under the action of lysosomal phosphatases within the macrophages, the encapsulated clodronate is gradually released and accumulates intracellularly. Upon reaching a certain concentration, the macrophages suffer irreversible damage, triggering apoptosis. Subsequently, the intracellular clodronate is released extracellularly. Free clodronate has a very short half-life and is excreted via urine.
Literature 1
Source: Macrophage depletion in inflamed rat knees prevents the activation of synovial mesenchymal stem cells by weakening Nampt and Spp1 signaling. Inflamm Regen. (IF=6.6, Q1)
This study applies Clodronate Liposomes in a rat model of inflammatory knee joints.
Depletion Method:
Ten-week-old male Lewis rats were used to establish an acute knee synovitis model induced by carrageenan. For macrophage depletion, 50 μL (0.1 mg) of Clodronate Liposomes was injected intra-articularly every 3 days for a total of two injections. The control group received empty liposomes.
Depletion Efficacy:
Immunohistochemistry and flow cytometry for CD68 showed that Clodronate Liposome injections significantly reduced the number of macrophages. Clodronate effectively depleted CD68+ macrophages in both normal and model knee joints. Furthermore, macrophage depletion in the model knee joints did not alter the ratio of M1 (CD80/CD86) to M2 (CD206) phenotypes.
Literature 2
Source:
Mussel inspired 3D elastomer enabled rapid calvarial bone regeneration through recruiting more osteoprogenitors from the dura mater. Regen Biomater. (IF=8.1, Q1)
This study applies Clodronate Liposomes in a rat calvarial defect model.
Depletion Method:
Four-week-old male SD rats were used to establish an 8 mm calvarial defect model. The experimental groups were divided as follows:
Experimental Group (C15G85-PDA + Clodronate): Received local injections of Clodronate Liposomes to deplete macrophages.
Control Group (C15G85-PDA + PBS): Received local injections of PBS liposomes as a control.
A dose of 50 μL (0.1 mg) was administered locally to the defect area. Injections were given every 2 days for the first 2 weeks after scaffold implantation, followed by once weekly until sampling.
Depletion Efficacy:
Immunofluorescence results from samples harvested 2 weeks after scaffold implantation showed a significant depletion effect on CD206+ M2 macrophages in the Clodronate Liposome-injected samples.
Literature 3
Source:
Ribeiro-Machado C, Santos SG, Amaral IA, et al. Macrophage-based therapy for intervertebral disc herniation: preclinical proof-of-concept. NPJ Regen Med. (IF=6.5, Q1)
This study applies Clodronate Liposomes in a rat model of intervertebral disc (IVD) herniation.
Depletion Method:
Male Lewis (LEW/Crl) rats (2–3 months old) were used to establish a caudal IVD herniation model. Percutaneous needle puncture of the caudal intervertebral discs (Co5/6, Co6/7, Co7/8) was performed to induce annulus fibrosus rupture and nucleus pulposus protrusion, simulating clinical disc herniation and confirming the necessity of macrophages for spontaneous regression.
For macrophage depletion, Clodronate Liposomes were administered via tail vein injection at a dose of 100 μL / 10 g. In the CLP2w group, injections were given every 3 days starting from the day of modeling and continued for 2 weeks post-surgery. In the CLP6w group, injections were given every 5 days starting from 2 weeks post-surgery and continued for 6 weeks. The control group received empty liposomes. All animals were harvested for analysis 6 weeks post-surgery.
Depletion Efficacy:
Flow cytometry results demonstrated significant macrophage depletion in peripheral blood (Fig. b) and the spleen (Fig. c). The positivity rate of CD172+CD11b/c+ myeloid cells was significantly decreased in the CLP2W and CLP6W groups compared to the control group.
Literature 4
Source:
Macrophage depletion in stellate ganglia alleviates cardiac sympathetic overactivation and ventricular arrhythmogenesis by attenuating neuroinflammation in heart failure. Basic Res Cardiol. (IF=8.1, Q1)
This study applies Clodronate Liposomes in a rat model of myocardial infarction (MI)-induced chronic heart failure.
Depletion Method:
Male SD rats (6–7 weeks old, 180–200 g) underwent left anterior descending coronary artery ligation to establish an MI-induced chronic heart failure model. For macrophage depletion, a single local microinjection of Clodronate Liposomes was administered bilaterally into the stellate ganglia (SG) during the stable heart failure phase (12 weeks post-modeling). Each side received 40 μg (80 μg total). Samples were harvested 1 week after injection. The control group received empty liposomes.
Depletion Efficacy:
Flow cytometry results showed that Clodronate Liposome injection alleviated the increase in macrophages within the stellate ganglia caused by heart failure. Compared to the empty liposome group, CD11b+CD45+ macrophages were significantly reduced.
Literature 5
Source:
Xia L, Cui C, Li J, Cheng J, Xia Y. Comparative study on two methods for clearing uterine endometrial macrophages in rats. Chin J Comp Med. 2024, 34(4): 84-91. DOI: 10.3969/j.issn.1671-7856.2024.04.010
This study applies Clodronate Liposomes to deplete macrophages in the rat uterine endometrium.
Depletion Method:
Normal female SD rats (8 weeks old) were divided into 6 groups (n=8 per group), with samples harvested 48 hours post-injection:
- Unilateral Control Group: Left uterine cavity injected with 100 μL PBS liposomes.
- Unilateral Depletion Group: Right uterine cavity injected with 100 μL Clodronate Liposomes.
- Bilateral Control Group: Both uterine cavities injected with 100 μL PBS liposomes each.
- Bilateral Depletion Group: Both uterine cavities injected with 100 μL Clodronate Liposomes each.
- Systemic Control Group: Tail vein injection of 500 μL PBS liposomes.
- Systemic Depletion Group: Tail vein injection of 500 μL Clodronate Liposomes.
Depletion Efficacy:
As shown by immunohistochemistry (CD68) and flow cytometry (CD68+CD45), bilateral uterine cavity injection achieved significantly higher depletion efficiency of endometrial macrophages compared to tail vein injection, without affecting ovarian macrophages. This makes it the optimal method for establishing a locally specific macrophage depletion model in the uterus.
Related Product
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40339ES05/08/10 |
2 + 2 mL 5 + 5 mL 10 + 10 mL |