Pub Date : 2025-09-26DOI: 10.1038/s41684-025-01617-1
Joel Jovanovic, Megan L. Stone, Samantha R. Dooyema, Yuankai K. Tao, Sabine Fuhrmann, Edward M. Levine
Small molecules such as PLX5622 for microglia depletion and tamoxifen for inducible Cre recombination are commonly used in mouse research. Traditional application methods such as drug-infused chow, oral gavage or injections have limitations, including uncontrolled dosing (chow) or risk of injury and/or stress (gavage or injections). Here, to address these issues, we have developed an alternative oral drug delivery system using a gel-based rodent maintenance diet that allows for controlled consumption and adjustment of dosage and is suitable for water-insoluble small molecules. We tested DietGel 93M (93M) infused with PLX5622 (0.8 mg/g and 2.0 mg/g) in the Cx3cr1gfp/+ retinal microglia reporter mouse and tamoxifen-infused 93M (0.3125 mg/g) in the Rlbp1-CreERT2;Rosaai14 mouse with an inducible tdTomato reporter in retinal Müller glia. Mice were single caged and received daily batches of PLX5622-infused 93M over 14 days or tamoxifen-infused 93M for 1 or 3 days followed by a 14-day observation period. Longitudinal scanning laser ophthalmoscopy in vivo and fixed-tissue imaging were used to track GFP and tdTomato expression. Following evaluation of a suitable 93M consumption rate to sustain body weight, the PLX5622-93M diet at both concentrations tested showed a 94% microglia depletion rate at 3 days and >99% after 1 and 2 weeks. The tamoxifen-93M diet confirmed suitability for inducible Cre recombination, with significant treatment time-dependent efficacy and a positive correlation between total tamoxifen dose and tdTomato expression. This study demonstrates that a diet gel-based drug delivery system offers a minimally invasive alternative to current drug application methods for PLX5622 and tamoxifen. This approach could be useful for other drugs or tissues beyond the retina. Jovanovic et al. show that a gel-based diet can be used as a minimally invasive alternative system for the delivery of small molecules for microglia depletion and inducible Cre recombination in mice.
{"title":"Diet gel-based oral drug delivery system for controlled dosing of small molecules for microglia depletion and inducible Cre recombination in mice","authors":"Joel Jovanovic, Megan L. Stone, Samantha R. Dooyema, Yuankai K. Tao, Sabine Fuhrmann, Edward M. Levine","doi":"10.1038/s41684-025-01617-1","DOIUrl":"10.1038/s41684-025-01617-1","url":null,"abstract":"Small molecules such as PLX5622 for microglia depletion and tamoxifen for inducible Cre recombination are commonly used in mouse research. Traditional application methods such as drug-infused chow, oral gavage or injections have limitations, including uncontrolled dosing (chow) or risk of injury and/or stress (gavage or injections). Here, to address these issues, we have developed an alternative oral drug delivery system using a gel-based rodent maintenance diet that allows for controlled consumption and adjustment of dosage and is suitable for water-insoluble small molecules. We tested DietGel 93M (93M) infused with PLX5622 (0.8 mg/g and 2.0 mg/g) in the Cx3cr1gfp/+ retinal microglia reporter mouse and tamoxifen-infused 93M (0.3125 mg/g) in the Rlbp1-CreERT2;Rosaai14 mouse with an inducible tdTomato reporter in retinal Müller glia. Mice were single caged and received daily batches of PLX5622-infused 93M over 14 days or tamoxifen-infused 93M for 1 or 3 days followed by a 14-day observation period. Longitudinal scanning laser ophthalmoscopy in vivo and fixed-tissue imaging were used to track GFP and tdTomato expression. Following evaluation of a suitable 93M consumption rate to sustain body weight, the PLX5622-93M diet at both concentrations tested showed a 94% microglia depletion rate at 3 days and >99% after 1 and 2 weeks. The tamoxifen-93M diet confirmed suitability for inducible Cre recombination, with significant treatment time-dependent efficacy and a positive correlation between total tamoxifen dose and tdTomato expression. This study demonstrates that a diet gel-based drug delivery system offers a minimally invasive alternative to current drug application methods for PLX5622 and tamoxifen. This approach could be useful for other drugs or tissues beyond the retina. Jovanovic et al. show that a gel-based diet can be used as a minimally invasive alternative system for the delivery of small molecules for microglia depletion and inducible Cre recombination in mice.","PeriodicalId":17936,"journal":{"name":"Lab Animal","volume":"54 10","pages":"278-285"},"PeriodicalIF":3.9,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.comhttps://www.nature.com/articles/s41684-025-01617-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145176416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-25DOI: 10.1038/s41684-025-01619-z
Charlotte Harrison
Researchers are increasingly using organ-on-chips and organoids alongside or instead of animals to model drug safety, biological mechanisms and rare diseases.
研究人员越来越多地将芯片上的器官和类器官与动物一起或代替动物来模拟药物安全性、生物机制和罕见疾病。
{"title":"New approach methodologies gain momentum, providing human-relevant alternatives to animal models","authors":"Charlotte Harrison","doi":"10.1038/s41684-025-01619-z","DOIUrl":"10.1038/s41684-025-01619-z","url":null,"abstract":"Researchers are increasingly using organ-on-chips and organoids alongside or instead of animals to model drug safety, biological mechanisms and rare diseases.","PeriodicalId":17936,"journal":{"name":"Lab Animal","volume":"54 10","pages":"250-253"},"PeriodicalIF":3.9,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.comhttps://www.nature.com/articles/s41684-025-01619-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145140238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-24DOI: 10.1038/s41684-025-01601-9
Omar A. Selim, Aida Sarcon, Mehmet Tunaboylu, Chunfeng Zhao, Steven L. Moran
Rhabdomyolysis following revascularization of the ischemic upper extremity can lead to life- and limb-threatening sequelae. In the context of replantations and vascularized composite allografting, a reconstructive procedure usually reserved for upper limb amputees, prolonged tissue ischemia is detrimental to extremity functional recovery. Currently, validated survival small animal models of extremity reperfusion injury that permit longitudinal assessment of limb function are lacking. So far, studies that evaluated reperfusion injury-induced neuromuscular impairment have relied on terminal ex vivo procedures and did not provide clinically translatable measurements. Here we present a reliable rat model of extremity post-reperfusion syndrome (PRS) that comprehensively recapitulates the biochemical hallmarks of rhabdomyolysis secondary to upper-extremity reperfusion injury and allows the monitoring of in vivo upper limb function using clinically relevant electrodiagnostic and kinematic metrics. In addition to inducing severe metabolic derangements, our forelimb PRS model provided insights on gross motor and electrophysiological alterations following upper-extremity reperfusion injury. We identify gait coordination parameters—such as stride frequency and the forelimb–hindlimb coordination index—and electrophysiological metrics, including compound muscle action potential amplitude, as objective and noninvasive outcome measures for assessing limb function in small animal models of extremity PRS. This comprehensive, validated functional model can serve as an invaluable tool to evaluate therapeutics or preconditioning regimens to attenuate PRS and mitigate resulting neuromuscular dysfunction. The authors report the development of a new rat model of forelimb ischemia–reperfusion injury, characterized by motor coordination deficits, impairment of neuromuscular transmission and serum biochemical and inflammatory changes.
{"title":"A longitudinal rat forelimb model for assessing in vivo neuromuscular function following extremity reperfusion injury","authors":"Omar A. Selim, Aida Sarcon, Mehmet Tunaboylu, Chunfeng Zhao, Steven L. Moran","doi":"10.1038/s41684-025-01601-9","DOIUrl":"10.1038/s41684-025-01601-9","url":null,"abstract":"Rhabdomyolysis following revascularization of the ischemic upper extremity can lead to life- and limb-threatening sequelae. In the context of replantations and vascularized composite allografting, a reconstructive procedure usually reserved for upper limb amputees, prolonged tissue ischemia is detrimental to extremity functional recovery. Currently, validated survival small animal models of extremity reperfusion injury that permit longitudinal assessment of limb function are lacking. So far, studies that evaluated reperfusion injury-induced neuromuscular impairment have relied on terminal ex vivo procedures and did not provide clinically translatable measurements. Here we present a reliable rat model of extremity post-reperfusion syndrome (PRS) that comprehensively recapitulates the biochemical hallmarks of rhabdomyolysis secondary to upper-extremity reperfusion injury and allows the monitoring of in vivo upper limb function using clinically relevant electrodiagnostic and kinematic metrics. In addition to inducing severe metabolic derangements, our forelimb PRS model provided insights on gross motor and electrophysiological alterations following upper-extremity reperfusion injury. We identify gait coordination parameters—such as stride frequency and the forelimb–hindlimb coordination index—and electrophysiological metrics, including compound muscle action potential amplitude, as objective and noninvasive outcome measures for assessing limb function in small animal models of extremity PRS. This comprehensive, validated functional model can serve as an invaluable tool to evaluate therapeutics or preconditioning regimens to attenuate PRS and mitigate resulting neuromuscular dysfunction. The authors report the development of a new rat model of forelimb ischemia–reperfusion injury, characterized by motor coordination deficits, impairment of neuromuscular transmission and serum biochemical and inflammatory changes.","PeriodicalId":17936,"journal":{"name":"Lab Animal","volume":"54 10","pages":"259-269"},"PeriodicalIF":3.9,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145137949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Anesthesia is indispensable for minimizing stress during invasive procedures. However, anesthesia can induce undesired effects on the organism and its physiological homeostasis. In experiments involving animals, these consequences may reduce animal welfare and alter experimental outcomes. Moreover, most of the studies characterizing the effects of murine anesthetic protocols on animal welfare do not explore the impact of prolonged anesthesia for procedures lasting more than 2 h. Here we investigated the effect of prolonged anesthesia on vital parameters and immune responses to vaccination, comparing isoflurane (Iso), ketamine–xylazine (KX), and KX with oxygen supplementation (KXO2), in the presence or absence of buprenorphine (BPP). KX induced hypoxia and 100% mortality, which were prevented by oxygen supplementation (KXO2) and were not associated with BPP. By contrast, Iso induced safe and fast induction and recovery. Furthermore, we investigated the effects of these protocols on the immune responses and motility of immune cells following vaccination. The results showed that KX reduced immune cell numbers and increased cell death, complemented by elevated levels of the inflammatory proteins IL-6 and IFNγ. In addition, KX altered the motility patterns of T cells, B cells and neutrophils, potentially influenced by hypoxia. Conversely, Iso exhibited fewer immune artifacts, regardless of BPP. These findings highlight the importance of evaluating anesthesia protocols with respect to animal welfare and experimental reproducibility, especially for immunological studies. Oxygen supplementation emerged as an important refinement to mitigate hypoxia in KX. Iso showed superior safety and fewer artifacts compared with KX and KXO2, demonstrating its suitability for immunological research and intravital microscopy. The study reveals that long-term anesthesia with ketamine–xylazine can induce hypoxia and mortality in mice, whereas oxygen supplementation mitigates these effects. As an alternative, isoflurane showed superior safety and fewer effects on the immune system.
{"title":"Impact of prolonged isoflurane or ketamine–xylazine anesthesia with or without buprenorphine and oxygen on mouse vitals and immune responses","authors":"Tommaso Virgilio, Irene Latino, Chiara Pizzichetti, Kamil Chahine, Arianna Capucetti, Carlotta Detotto, Alessandra Bergadano, Santiago F.Gonzalez","doi":"10.1038/s41684-025-01614-4","DOIUrl":"10.1038/s41684-025-01614-4","url":null,"abstract":"Anesthesia is indispensable for minimizing stress during invasive procedures. However, anesthesia can induce undesired effects on the organism and its physiological homeostasis. In experiments involving animals, these consequences may reduce animal welfare and alter experimental outcomes. Moreover, most of the studies characterizing the effects of murine anesthetic protocols on animal welfare do not explore the impact of prolonged anesthesia for procedures lasting more than 2 h. Here we investigated the effect of prolonged anesthesia on vital parameters and immune responses to vaccination, comparing isoflurane (Iso), ketamine–xylazine (KX), and KX with oxygen supplementation (KXO2), in the presence or absence of buprenorphine (BPP). KX induced hypoxia and 100% mortality, which were prevented by oxygen supplementation (KXO2) and were not associated with BPP. By contrast, Iso induced safe and fast induction and recovery. Furthermore, we investigated the effects of these protocols on the immune responses and motility of immune cells following vaccination. The results showed that KX reduced immune cell numbers and increased cell death, complemented by elevated levels of the inflammatory proteins IL-6 and IFNγ. In addition, KX altered the motility patterns of T cells, B cells and neutrophils, potentially influenced by hypoxia. Conversely, Iso exhibited fewer immune artifacts, regardless of BPP. These findings highlight the importance of evaluating anesthesia protocols with respect to animal welfare and experimental reproducibility, especially for immunological studies. Oxygen supplementation emerged as an important refinement to mitigate hypoxia in KX. Iso showed superior safety and fewer artifacts compared with KX and KXO2, demonstrating its suitability for immunological research and intravital microscopy. The study reveals that long-term anesthesia with ketamine–xylazine can induce hypoxia and mortality in mice, whereas oxygen supplementation mitigates these effects. As an alternative, isoflurane showed superior safety and fewer effects on the immune system.","PeriodicalId":17936,"journal":{"name":"Lab Animal","volume":"54 10","pages":"270-277"},"PeriodicalIF":3.9,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.comhttps://www.nature.com/articles/s41684-025-01614-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145083510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-25DOI: 10.1038/s41684-025-01606-4
Alexandra Le Bras
{"title":"A pig model of Angelman syndrome","authors":"Alexandra Le Bras","doi":"10.1038/s41684-025-01606-4","DOIUrl":"10.1038/s41684-025-01606-4","url":null,"abstract":"","PeriodicalId":17936,"journal":{"name":"Lab Animal","volume":"54 9","pages":"223-223"},"PeriodicalIF":3.9,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144900198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-25DOI: 10.1038/s41684-025-01607-3
Jorge Ferreira
{"title":"Channeling male aggression to other behaviors","authors":"Jorge Ferreira","doi":"10.1038/s41684-025-01607-3","DOIUrl":"10.1038/s41684-025-01607-3","url":null,"abstract":"","PeriodicalId":17936,"journal":{"name":"Lab Animal","volume":"54 9","pages":"224-224"},"PeriodicalIF":3.9,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144900193","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-25DOI: 10.1038/s41684-025-01610-8
Jorge Ferreira
{"title":"Lymphatic system role in ALS","authors":"Jorge Ferreira","doi":"10.1038/s41684-025-01610-8","DOIUrl":"10.1038/s41684-025-01610-8","url":null,"abstract":"","PeriodicalId":17936,"journal":{"name":"Lab Animal","volume":"54 9","pages":"224-224"},"PeriodicalIF":3.9,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144900197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-25DOI: 10.1038/s41684-025-01609-1
Jorge Ferreira
{"title":"Drosophila functional model of atrial fibrillation","authors":"Jorge Ferreira","doi":"10.1038/s41684-025-01609-1","DOIUrl":"10.1038/s41684-025-01609-1","url":null,"abstract":"","PeriodicalId":17936,"journal":{"name":"Lab Animal","volume":"54 9","pages":"224-224"},"PeriodicalIF":3.9,"publicationDate":"2025-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144900200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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