The role of light emitting diode in wound healing: A systematic review of experimental studies.

Wounds represent a growing global issue demanding increased attention. To expedite wound healing, technologies are under development, and light emitting diode (LED) devices of varying wavelengths are being explored for their stimulating influence on the healing process. This article presents a systematic literature review aiming to compile, organize, and analyze the impacts of LED devices on wound healing. This review is registered on the PROSPERO platform [CRD42023403870]. Two blinded authors conducted searches in the Pubmed, Web of Science, Scopus, Embase, and ScienceDirect databases. In vitro and in vivo experimental studies assessing LED utilization in the wound healing process were included. The search yielded 1010 studies, of which 27 were included in the review. It was identified that LED stimulates different healing pathways, promoting enhanced cell proliferation and migration, angiogenesis stimulation, increased collagen deposition, and modulation of the inflammatory response. Thus, it can be concluded that the LED stimulates cellular and molecular processes contingent on the utilized parameters. The effects depend on the standards used. Cell migration and proliferation were better influenced by green and red LED. The extracellular matrix components and angiogenesis were regulated by all wavelengths and the modulation of inflammation was mediated by green, red, and infrared LEDs.

Prediction of the minimum amount of anti-adhesive agent required for entire intra-abdominal cavity using fluorescent dye.

PURPOSE: Studies on the appropriate amount of anti-adhesive agents for preventing postoperative adhesion are lacking. This animal study aimed to investigate the distribution of an anti-adhesive agent in the abdominal cavity and estimate the necessary amount to cover the entire cavity. METHODS: Fluorescent dye Flamma-552 was conjugated to Guardix-sol to create Guardix-Flamma, which was laparoscopically applied to the abdominal cavity of two 10-kg pigs in different amounts: 15 mL for G1 and 35 mL for G2. After 24 hours, the distribution of Guardix-Flamma was examined under the near-infrared mode of the laparoscope, and the thickness was measured in tissues from the omentum, small, and large intestine by immunohistochemistry. RESULTS: The average area of the abdominal cavity in 10 kg pigs was 2,755 cm2. Guardix-Flamma fluorescence was detected in the greater omentum, ascites in the pelvis, and right quadrant area in G1, whereas in G2, it was detected everywhere. On average, the total thickness of G1 and G2 were 12.68 ± 9.80 µm and 18.16 ± 15.57 µm, respectively. Guardix-Flamma thickness applied to the omentum, small, and large intestines of G2 were 1.31-, 1.45-, and 1.49-times thicker than those of G1, respectively, and were all statistically significant (P < 0.05). CONCLUSION: The entire abdominal cavity of the 10 kg pig was not evenly covered with 15 mL of Guardix. Although 35 mL of Guardix is sufficient to cover the same area with an average thickness of 18 µm, further studies should evaluate the minimum thickness required for an effective anti-adhesive function.

Investigation through Animal-Computer Interaction: A Proof-of-Concept Study for the Behavioural Experimentation of Colour Vision in Zoo-Housed Primates.

Zoos are an important repository of animals, which have a wide range of visual systems, providing excellent opportunities to investigate many comparative questions in sensory ecology. However, behavioural testing must be carried out in an animal welfare-friendly manner, which is practical for zoo staff. Here, we present a proof-of-concept study to facilitate behavioural research on the sensory ecology of captive primates. A system consisting of a tablet computer and an automated feeder connected wirelessly was developed and presented to captive primate species to evaluate interactions with and without previous training. A colour stimulus, analogous to the Ishihara test, was used to check the level of interaction with the device, supporting future studies on sensory ecology with zoo animals. Animals were able to use the system successfully and displayed signs of learning to discriminate between the visual stimuli presented. We identified no risk for small primates in their interactions with the experimental setup without the presence of keepers. The use of electronic devices should be approached with caution to prevent accidents, as a standard practice for environmental enrichment for larger animals (e.g., spider monkeys). In the long term, the system developed here will allow us to address complex comparative questions about the functions of different visual systems in captive animals (i.e., dichromatic, trichromatic, etc.).

Peri-implantitis induction and resolution around zirconia versus titanium implants.

BACKGROUND: This study compared titanium and zirconia implant ligature-induced peri-implant defect progression and response to regenerative surgical intervention. METHODS: Eight tissue-level endosseous implants were placed in 6 mixed-breed foxhounds, with 2 zirconia and 2 titanium alternating in each hemimandible. Cotton ligatures were placed subgingivally for 16 weeks followed by 8 weeks of spontaneous progression. Standardized radiographs were captured every 2 weeks to evaluate the rate of bone loss. Regenerative surgery was performed utilizing water-jet decontamination, enamel matrix derivative, and locally harvested autogenous bone. After 16 weeks of healing, final radiographic bone levels as well as probing depths, recession, and clinical attachment levels were assessed. RESULTS: All 48 implants integrated successfully. The final average post-ligature radiographic defects were 2.88 and 3.05 mm for titanium and zirconia implants, respectively. There was no significant difference between materials in the rate of radiographic bone loss (p = 0.09). Following regenerative surgery, the total average amount of radiographic bone gain was 1.41 and 1.20 mm for titanium and zirconia, respectively. The percentage of defect fill was 51.56% and 37.98% (p = 0.03) for titanium and zirconia, respectively. Inter-group differences were minimal for clinical parameters at the time of sacrifice including periodontal pocket depths (p = 0.81), recession (p = 0.98), or clinical attachment levels (p = 0.51). CONCLUSIONS: No significant difference was found in the rate of peri-implant defect development between titanium and zirconia implants. Both materials gained significant radiographic bone following regenerative surgery with significantly greater defect percentage fill in titanium implants. The final clinical parameters were similar in both groups.

Efficacy of robot arm-assisted endoscopic submucosal dissection in live porcine stomach (with video).

Endoscopic submucosal dissection (ESD) is technically challenging and requires a high level of skill. However, there is no effective method of exposing the submucosal plane during dissection. In this study, the efficacy of robot arm-assisted tissue traction for gastric ESD was evaluated using an in vivo porcine model. The stomach of each pig was divided into eight locations. In the conventional ESD (C-ESD) group, one ESD was performed at each location (N = 8). In the robot arm-assisted ESD (R-ESD) group, two ESDs were performed at each location (N = 16). The primary endpoint was the submucosal dissection speed (mm2/s). The robot arm could apply tissue traction in the desired direction and successfully expose the submucosal plane during submucosal dissection in all lesion locations. The submucosal dissection speed was significantly faster in the R-ESD group than in the C-ESD group (p = 0.005). The blind dissection rate was significantly lower in the R-ESD group (P = 0.000). The robotic arm-assisted traction in ESD enabled a significant improvement in submucosal dissection speed, blind dissection rate which suggests the potential for making ESD easier and enhancing procedural efficiency and safety.

A Novel Minimally Invasive Surgically Induced Skeletal Muscle Injury Model in Sheep.

Sports-related muscle injuries account for 10-55% of all injuries, which is a growing concern, especially given the aging world population. To evaluate the process of skeletal muscle injury and compare it with muscle lesions observed in humans, we developed a novel in vivo model in sheep. In this model, muscle injury was induced by an ultrasound-guided transverse biopsy at the myotendinous junction of the medial gastrocnemius muscle. Twelve male sheep were examined at 3, 7, 14, and 28 days post-injury. Histological, immunofluorescence, and MRI analyses indicate that our sheep model could resemble key human clinicopathological features. Statistically significant differences (p < 0.05) were observed in collagen I, dMHC, α-SMA, and CD68 immunohistochemical detection when comparing injured and healthy muscles. The injured gastrocnemius muscle exhibited elevated levels of type I collagen, infiltration of CD68(+) macrophages, angiogenesis, and the emergence of newly regenerated dMHC(+) myofibers, which persisted for up to 4 weeks post-injury. Similarly, the progression of muscle injury in the sheep model was assessed using advanced clinical 3 T MRI and compared with MRI scans from human patients. The data indicate that the sheep muscle injury model presents features similar to those observed in human skeletal muscle injuries. This makes it a valuable large animal model for studying muscle injuries and developing novel therapeutic strategies.

Utility of pemafibrate in nonalcoholic steatohepatitis model mice induced by a choline-deficient, high-fat diet and dextran sulfate sodium.

Aim: The purpose of this study was to examine the effect of pemafibrate in a murine model of non-alcoholic steatohepatitis (NASH). Methods: Forty-two, 19-week-old, male, C57BL/6J mice were divided into three groups: a Control group (n = 14), a dextran sulfate sodium (DSS) group (n = 14), and a DSS + PEM group (n = 14). All mice were given a standard rodent diet for the first week, followed by a choline-deficient, high-fat diet (CDHF) for the next 12 weeks. The 22nd day after the animals arrived was taken as Day 1 of the experiment. The Control group continued the CDHF diet and MilliQ water. The DSS group continued the CDHF diet, but starting on Day 1, the group received 0.8 % DSS to drink for 7 consecutive days, followed by MilliQ water for 10 days; this was taken as one course, and it was repeated on the same schedule until autopsy. The DSS + PEM group received the CDHF diet with PEM 0.1 mg/kg/day. Their drinking water was the same as that of the DSS group. On Seven animals from each group were autopsied on each of Day 50 and Day 120, and histopathological and immunohistochemical examinations, as well as quantitative RNA and cytokine measurements, of autopsied mice were performed. Results: Pemafibrate improved hepatic steatosis (decreased steatosis area), improved liver inflammation enhanced by DSS (decreased aspartate transaminase and alanine aminotransferase), improved hepatic fibrosis promoted by DSS (decreased fibrotic areas and a marker of fibrosis), inhibited tumorigenesis, and decreased intestinal inflammation in the NASH model mice. Conclusions: In a murine model of NASH, mixing PEM 0.1 mg/kg/day into the diet inhibited disease progression and tumor formation.

The activin/BMP-2 chimera AB204 promotes periodontal tissue regeneration in a buccal dehiscence model: a pilot study.

PURPOSE: A combination of activin and bone morphogenetic protein-2 (BMP-2), termed AB204, has been shown to improve osteogenic potential with fewer side effects than BMP-2 alone. This study was performed to evaluate the effect of AB204 on periodontal tissue regeneration in a dog buccal dehiscence model. METHODS: Buccal dehiscence defects were created on the maxillary premolars (P1, P2, and P3) of 6 mongrel dogs. After 5 weeks, the dogs were randomly assigned to 1 of 3 groups: the control, collagen matrix (CM), and CM/AB204 groups. Grafting procedures were then performed. The dogs were sacrificed 8 weeks after the grafting procedure, and volumetric and histological analyses were conducted. RESULTS: The thickness of the buccal gingiva in the CM/AB204 group was greater than those in the other groups at 2 weeks (P<0.05). The ridge width in the AB204/CM group exceeded the width in the other groups at 4 and 8 weeks; however, the difference was not statistically significant. Histological analysis revealed that the CM/AB204 group demonstrated the formation of new bone surrounded by newly formed periodontal ligament and cementum (P=0.035). CONCLUSIONS: The combined application of CM and AB204 shows promise in facilitating the regeneration of periodontal attachment, including the formation of new bone, cementum, and periodontal ligament.

60 Years of the 3Rs symposium: Lessons learned and the road ahead.

When The Principles of Humane Experimental Technique was published in 1959, authors William Russell and Rex Burch had a modest goal: to make researchers think about what they were doing in the laboratory ­ and to do it more humanely. Sixty years later, their groundbreaking book was celebrated for inspiring a revolution in science and launching a new field: The 3Rs of alternatives to animal experimentation. On November 22, 2019, some pioneering and leading scientists and researchers in the field gathered at the Johns Hopkins Bloomberg School of Public Health in Bal­timore for the 60 Years of the 3Rs Symposium: Lessons Learned and the Road Ahead. The event was sponsored by the Johns Hopkins Center for Alternatives to Animal Testing (CAAT), the Foundation for Chemistry Research and Initiatives, the Alternative Research & Development Foundation (ARDF), the American Cleaning Institute (ACI), the International Fragrance Association (IFRA), the Institute for In Vitro Sciences (IIVS), John "Jack" R. Fowle III, and the Society of Toxicology (SoT). Fourteen pres­entations shared the history behind the groundbreaking publication, international efforts to achieve its aims, stumbling blocks to progress, as well as remarkable achievements. The day was a tribute to Russell and Burch, and a testament to what is possible when people from many walks of life ­ science, government, and industry ­ work toward a common goal.

William Russell and Rex Burch published their book The Principles of Humane Experimental Technique in 1959. The book encouraged researchers to replace animal experiments where it was possible, to refine experiments with animals in order to reduce their suffering, and to reduce the number of animals that had to be used for experiments to the minimum. Sixty years later, a group of pioneering and leading scientists and researchers in the field gathered to share how the publi­cation came about and how the vision inspired international collaborations and successes on many different levels including new laws. The paper includes an overview of important milestones in the history of alternatives to animal experimentation.

[Exavir: Implementation and evaluation of experimental pharmacology skills acquisition by pharmacy students]. / Exavir : mise en place et évaluation de l'acquisition de compétences en pharmacologie expérimentale par des étudiants en pharmacie.

With the evolution of European and French regulations on animal experimentation in higher education, taking greater account of animal welfare, the University of Angers has developed a virtual animal experimentation software named Exavir. Used for practical work (PW) in physiology, pharmacology and toxicology in the Health, Sciences, and engineering curricula, Exavir can be used to simulate various experiments for teaching purposes, in vivo or ex vivo. Thanks to an original approach integrating serious games with different scenarios, students gain autonomy and become directly involved in their learning. In addition, Exavir's collaborative and participative development approach fosters inter-university partnerships and the emergence of innovative teaching methods. A hybrid pilot study carried out on a sample of 22 students in the Pharmacy Department of the Faculty of Health showed that Exavir improved students' acquisition of teaching skills in both physiology and pharmacology, compared with practical work only based on animal organs. These encouraging results demonstrate for the first time the pedagogical advantages of Exavir and confirm the interest in developing such a platform. In this context, it appears that Exavir also opens up the possibility of adapting the practical work offered within universities, and thus responding to the changing ethical issues of the coming decades.

Experimental necrotizing enterocolitis using oral lipopolysaccharide and protective role of breastmilk. / Enterocolitis necrotizante experimental con lipopolisacárido oral y función protectora de la leche materna.

INTRODUCTION: Necrotizing enterocolitis (NEC) is a life-threatening condition that afflicts neonates. Breastfeeding has demonstrated to play a protective role against it. By administering lipopolysaccharides (LPS) orally in newborn rats (NBR), we have developed an experimental model to induce NEC-like gut damage. Our aim was to assess the macroscopic and microscopic appearance of the gut, to evaluate the presence of NEC and study the role of breast milk (BM). MATERIALS AND METHODS: NBR were divided into 3 groups: Group A (control, n= 10) remained with the mother, group B (LPS, n= 25) was isolated after birth, gavage-fed with special rat formula and oral LPS, then submitted to stress (hypoxia after gavage) and group c (BM, n= 12) was breastfed once after birth, then isolated, and submitted to stress like group B. On day 4, NBR were sacrificed, and intestine was harvested and assessed. RESULTS: In the control group NEC was not present either macroscopically or histologically. Both groups submitted to stress (B and C) presented a global incidence of NEC of 73%. Most of group B developed histologic signs of NEC (85%) and group C showed a statistically lower incidence of NEC (50%, p= 0.04), playing the BM a protective role against NEC (OR= 0.19; 95% CI: 0.40-0.904). CONCLUSION: Our model showed a significant incidence of NEC in NBR (73%) with the same protective role of BM as in newborn humans, achieving a reliable and reproducible experimental NEC model. This will allow us to investigate new potential therapeutic targets for a devastating disease that currently lacks treatment.

INTRODUCCION: La enterocolitis necrotizante (ECN) es una enfermedad potencialmente mortal que afecta a los neonatos, y frente a la que la leche materna ha demostrado tener un papel protector. Administrando lipopolisacáridos (LPS) por vía oral en ratas recién nacidas (RRN), hemos desarrollado un modelo experimental para inducir un daño intestinal similar al que provoca la ECN con objeto de evaluar el aspecto macroscópico y microscópico del intestino, y de ese modo, analizar la presencia de ECN y estudiar el papel que desempeña la leche materna (LM). MATERIAL Y METODOS: Las RRN se dividieron en tres grupos: el grupo A (control, n= 10) permaneció con su madre; el grupo B (LPS, n= 25) fue aislado tras el nacimiento, alimentado por sonda con una fórmula especial para ratas y LPS oral, y sometido a estrés (hipoxia tras sonda); y el grupo C (LM, n= 12) fue alimentado con leche materna tras el nacimiento y posteriormente aislado y sometido a estrés al igual que el grupo B. El día 4 se sacrificó a las RRN y se recuperaron sus intestinos para su posterior evaluación. RESULTADOS: En el grupo de control, no se observó ECN ni macroscópica ni histológicamente, mientras que los dos grupos sometidos a estrés (B y C) presentaron una incidencia global de la ECN del 73%. La mayoría de los sujetos del grupo B desarrollaron signos histológicos de ECN (85%), y los del grupo C registraron una incidencia de la ECN estadísticamente menor (50%, p= 0,04), lo que significa que la LM desempeña una función protectora frente a la ECN (OR= 0,19; IC 95%: 0,40-0,904). CONCLUSION: Nuestro modelo reveló una incidencia significativa de la ECN en RRN (73%), desempeñando la LM la misma función protectora que en el caso de los humanos recién nacidos, lo que significa que este modelo experimental de ECN es fiable y reproducible. Gracias a dicho logro, podremos investigar nuevos y potenciales objetivos terapéuticos para una peligrosa enfermedad que, a día de hoy, carece de tratamiento.

Phase-out planning for animal experimentation.

Since the late 2010s, the idea of phase-out planning for animal experimentation (PPAE) has come to the foreground of political debates, but central notions and arguments are understood differently by different participants and stand in need of clarification. This article draws on public communications on ten political projects related to PPAE to propose a philosophical explication of PPAE and to artic­ulate the proponents' central moral argument. According to the argument, the phase-out of animal experimentation is morally desirable, and planned interventions are both necessary and sufficient to achieve it. The normative and descriptive premises of the argument are stated and discussed, flagging questions that need answering for a more thorough assessment of the argument. This results in a series of seven action points for researchers and stakeholders of PPAE. The overall goal is to enable an open and productive discussion about PPAE in public, political, and academic settings.

In recent years, a new demand has entered the political arena: that the phase-out of animal experi­mentation should be planned. But it is important to understand exactly what this means. This article draws on ten documents from governments, parliaments, and NGOs to tease out what they mean by "planning the phase-out of animal experimentation." It also discusses the main argument that is advanced in favor of phase-out planning and highlights seven gaps in our knowledge that we should try to fill to move the discussion forward. In sum, the article is the first to explicitly define phase-out planning for animal experimentation and to directly discuss its pros and cons from a phil­osophical point of view. This is helpful in avoiding misunderstandings and talking past each other, enabling an open and productive debate.

Animal Research Regulation: Improving Decision-Making and Adopting a Transparent System to Address Concerns around Approval Rate of Experiments.

The use of nonhuman animals in biomedical research is regulated under stringent conditions, not only in response to societal attitudes towards animal experimentation but also because ethical responsibility in scientific research requires researchers and veterinarians to be more invested and aim to improve the welfare of animals used for experiments. Analyses of animal research oversight reveal the frequent approval of experiments, and the approval of some experiments has raised and continues to raise public concerns. Societal compliance is required for a consensus-based approach to animal research policy, prompting the need to have transparent discussions about oversight and the frequency of approvals. We discuss how frequent approval may be perceived and why it seems problematic from a societal perspective: the regulatory process exists to approve only legitimate experiments. Although some experiments remain unacceptable irrespective of their harm-benefit ratios, almost all experiments are approved. We explain some possible legitimate reasons for frequent approval and how the review process could be leading to the approval of illegitimate studies. To ensure transparency and improve public trust and understanding of oversight, we propose the adoption of a platform to inform society about how unethical experiments are screened out.

Fluoroscopy-guided high-intensity focused ultrasound ablation of the lumbar medial branch nerves: dose escalation study and comparison with radiofrequency ablation in a porcine model.

BACKGROUND: Radiofrequency ablation (RFA) is a common method for alleviating chronic back pain by targeting and ablating of facet joint sensory nerves. High-intensity focused ultrasound (HIFU) is an emerging, non-invasive, image-guided technology capable of providing thermal tissue ablation. While HIFU shows promise as a potentially superior option for ablating sensory nerves, its efficacy needs validation and comparison with existing methods. METHODS: Nine adult pigs underwent fluoroscopy-guided HIFU ablation of eight lumbar medial branch nerves, with varying acoustic energy levels: 1000 (N=3), 1500 (N=3), or 2000 (N=3) joules (J). An additional three animals underwent standard RFA (two 90 s long lesions at 80°C) of the same eight nerves. Following 2 days of neurobehavioral observation, all 12 animals were sacrificed. The targeted tissue was excised and subjected to macropathology and micropathology, with a primary focus on the medial branch nerves. RESULTS: The percentage of ablated nerves with HIFU was 71%, 86%, and 96% for 1000 J, 1500 J, and 2000 J, respectively. In contrast, RFA achieved a 50% ablation rate. No significant adverse events occurred during the procedure or follow-up period. CONCLUSIONS: These findings suggest that HIFU may be more effective than RFA in inducing thermal necrosis of the nerve.

Experimental analysis of femoral head intraosseous vascular anastomosis in the treatment of porcine subcapital femoral neck fractures.

Introduction: Femoral neck fractures are challenging injuries associated with a compromised blood supply to the femoral head, leading to a high risk of avascular necrosis and poor clinical outcomes. This study aimed to investigate the efficacy of femoral head intraosseous vascular anastomosis in the treatment of porcine sub-capital femoral neck fractures. Methods: Ten Landrace pigs were used as experimental animal models. The femoral head was completely removed after femoral neck sub-cephalic fracture. It was fixed on the medial side of the knee joint, and the blood supply to the femoral head was reconstructed by anastomosing the femoral head vessels. One week later, blood flow in the femoral head was observed by borehole, digital subtraction angiography examination, and hematoxylin and eosin staining. Further, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling tests were performed to detect pathological changes in the femoral head. Results: After one-week, digital subtraction angiography of the femoral head revealed a blood circulation rate of 70 %, and the blood seepage rate of the borehole was 80 %. Hematoxylin and eosin staining and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling test results showed that necrosis of bone marrow cells in the experimental group was significantly improved compared to that in the control group. Discussion: This study highlights the potential benefits of femoral head intraosseous vascular anastomosis in the treatment of porcine sub-capital femoral neck fractures. Further research and clinical trials are warranted to validate these findings and to explore the translational potential of this technique in human patients.

The First Steps on AOPs' Concepts, Development, and Applications in Teratology.

An Adverse Outcome Pathway (AOP) is an analytical model that describes, through a graphical representation, a linear sequence of biologically connected events at different levels of biological organization, causally leading to an adverse effect on human health or the environment. In general, AOPs are constructed based on five central principles: systematic development and review, chemical-agnostic, modular, networks, and living documents. Furthermore, AOPs have the potential to be used, for example, to investigate certain molecular targets; relate the regulation of specific genes or proteins among AOPs; extrapolate biological processes, pathways, or diseases from one species to another; and even predict adverse effects in particular populations. AOPs also emerge as an alternative to animal experimentation in studies of developmental malformations. It's even possible now to develop a quantitative AOP to predict teratogenic effects for some substances. However, the construction of high-quality AOPs requires standardization in the way these models are developed and reviewed, ensuring an adequate degree of flexibility and guaranteeing efficiency. The development of AOPs should strictly be based on the guidance documents developed by the OECD. Nevertheless, an important step for those developing AOPs is the choice of an apical endpoint or an initiating molecular event in order to initiate the construction of the pathway. Another crucial step is a systematic literature review based on the random combination of the blocks of information. With these two fundamental steps completed, it only remains to follow the guidance documents on Developing and Assessing Adverse Outcome Pathways and AOP Developers' Handbook supplement provided by the OECD to organize and construct an AOP. This modern approach will bring radical changes in the field of toxicity testing, regarding the prediction of apical toxic effects using molecular-level effects.

Safety of Bioplasma FDP and Hemopure in rhesus macaques after 30% hemorrhage.

Objectives: Prehospital transfusion can be life-saving when transport is delayed but conventional plasma, red cells, and whole blood are often unavailable out of hospital. Shelf-stable products are needed as a temporary bridge to in-hospital transfusion. Bioplasma FDP (freeze-dried plasma) and Hemopure (hemoglobin-based oxygen carrier; HBOC) are products with potential for prehospital use. In vivo use of these products together has not been reported. This study assessed the safety of intravenous administration of HBOC+FDP, relative to normal saline (NS), in rhesus macaques (RM). Methods: After 30% blood volume removal and 30 minutes in shock, animals were resuscitated with either NS or two units (RM size adjusted) each of HBOC+FDP during 60 minutes. Sequential blood samples were collected. After neurological assessment, animals were killed at 24 hours and tissues collected for histopathology. Results: Due to a shortage of RM during the COVID-19 pandemic, the study was stopped after nine animals (HBOC+FDP, seven; NS, two). All animals displayed physiologic and tissue changes consistent with hemorrhagic shock and recovered normally. There was no pattern of cardiovascular, blood gas, metabolic, coagulation, histologic, or neurological changes suggestive of risk associated with HBOC+FDP. Conclusion: There was no evidence of harm associated with the combined use of Hemopure and Bioplasma FDP. No differences were noted between groups in safety-related cardiovascular, pulmonary, renal or other organ or metabolic parameters. Hemostasis and thrombosis-related parameters were consistent with expected responses to hemorrhagic shock and did not differ between groups. All animals survived normally with intact neurological function. Level of evidence: Not applicable.

Inhibition of the glutamatergic PVT-NAc projections attenuates local anesthetic-induced neurotoxic behaviors.

INTRODUCTION: Local anesthetic-induced neurotoxicity contributes to perioperative nerve damage; however, the underlying mechanisms remain unclear. Here, we investigated the role of the paraventricular thalamus (PVT)-nucleus accumbens (NAc) projections in neurotoxicity induced by ropivacaine, a local anesthetic agent. METHODS: Ropivacaine (58 mg/kg, intraperitoneal administration) was used to construct the local anesthetic systemic toxicity (LAST) mice model. We first identified neural projections from the PVT to the NAc through the expression of a retrograde tracer and virus. The inhibitory viruses (rAAV-EF1α-DIO-hm4D(Gi)-mCherry-WPREs: AAV2/retro and rAAV-CaMKII-CRE-WPRE-hGh: AAV2/9) were injected into the mice model to assess the effects of the specific inhibition of the PVT-NAc pathway on neurological behaviors in the presence of clozapine-N-oxide. The inhibition of the PVT-NAc pathway was evaluated by immunofluorescence staining of c-Fos-positive neurons and Ca2+ signals in CaMKIIa neurons. RESULTS: We successfully identified a circuit connecting the PVT and NAc in C57BL/6 mice. Ropivacaine administration induced the activation of the PVT-NAc pathway and seizures. Specific inhibition of NAc-projecting CaMKII neurons in the PVT was sufficient to inhibit the neuronal activity in the NAc, which subsequently decreased ropivacaine-induced neurotoxicity. CONCLUSION: These results reveal the presence of a dedicated PVT-NAc circuit that regulates local anesthetic-induced neurotoxicity and provide a potential mechanistic explanation for the treatment and prevention of LAST.