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Noxious chemicals like chlorine induce extreme distress, pain, and irritation in exposed individuals, yet methods to evaluate pain-related behavioral responses are absent. It is also unknown whether analgesics would alleviate pain and physical discomfort induced by such noxious chemicals. The grimace scale (GS), which evaluates facial expression features such as orbital tightening (OT), is a valuable indicator of pain and distress in animals. However, conventional GS approaches are labor-intensive, prone to subjectivity, and lack quantitative precision. In this study, we employed machine learning with DeepLabCut to annotate key facial landmarks in video recordings of chlorine-exposed rats. Focusing on the superior and inferior eyelid margins and the medial and lateral canthi, we quantified eyelid distance and palpebral fissure width as measures of OT. Rigorous inclusion and exclusion criteria for annotated images were established to ensure accuracy and reproducibility. The quantitative GS in rats subjected to chlorine exposure was validated. Significant reductions in eyelid distance and palpebral fissure width were observed upon chlorine exposure as compared to unexposed control animals. Administration of the opioid analgesic buprenorphine significantly reduced the OT caused by chlorine. This study establishes a robust, quantitative method for assessing OT in chlorine-exposed rats using DeepLabCut, providing a scalable, objective tool for assessing pain induced by noxious chemicals in preclinical research. This study also suggests that opioids can alleviate pain and physical discomfort induced by inhalation of noxious chemicals, providing a new therapeutic strategy for managing the respiratory hazard of noxious chemicals.

Sulfur mustard (SM) is a highly toxic war chemical that causes significant morbidity and mortality and lacks any effective therapy. Rats exposed to aerosolized CEES (2-chloroethyl ethyl sulfide; 10% in ethanol), an analog of SM, developed acute respiratory distress syndrome (ARDS), which is characterized by increased inflammation, hypoxemia and impaired gas exchange. We observed elevated levels of extracellular nucleic acids (eNA) in the bronchoalveolar lavage fluid (BALF) of CEES-exposed animals. eNA can induce inflammation, coagulation and barrier dysfunction. Treatment with hexadimethrine bromide (HDMBr; 10 mg/kg), an eNA neutralizing agent, 2 h post-exposure, reduced lung injury, inhibited disruption of alveolar–capillary barrier, improved blood oxygenation (PaO2/FiO2 ratio), thus reversing ARDS symptoms. HDMBr treatment also reduced lung inflammation in the CEES-exposed animals by decreasing IL-6, IL-1A, CXCL-1 and CCL-2 mRNA levels in lung tissues and HMGB1 protein in BALF. Furthermore, HDMBr treatment also reduced levels of lung tissue factor and plasminogen activator inhibitor-1 indicating reduction in clot formation and increased fibrinolysis. Fibrin was reduced in BALF of the HDMBr-treated animals. This was further confirmed by histology that revealed diminished airway fibrin, epithelial sloughing and hyaline membrane in the lungs of HDMBr-treated animals. HDMBr completely rescued the CEES-associated mortality 12 h post-exposure when the survival rate in CEES-only group was just 50%. Experimental eNA treatment of cells caused increased inflammation that was reversed by HDMBr. These results demonstrate a role of eNA in the pathogenesis of CEES/SM-induced injury and that its neutralization can serve as a potential therapeutic approach in treating SM toxicity.

In autosomal dominant polycystic kidney disease (ADPKD), abnormal proliferation of tubular cells drives cyst development and growth. Sirolimus, an inhibitor of the protein kinase mammalian target of rapamycin (mTOR) and a potent anti-proliferative agent, decreases cyst growth in several genetically distinct rodent models of polycystic kidney disease (PKD). We determined here the effect of sirolimus on renal cyst growth in Pkd2WS25/− mice; an ortholog of human ADPKD involving mutation of the Pkd2 gene. In Pkd2WS25/− mice treated with sirolimus, both the two kidney/total body weight (2K/TBW) ratio and the cyst volume density (CVD) were significantly decreased by over half compared with untreated mice suffering with PKD. However, there was no effect on the increased blood urea nitrogen (BUN) levels as an index of kidney function. There are two distinct complexes containing mTOR depending on its binding partners: mTORC1 and mTORC2. Western blot analysis of whole kidney lysates and immunohistochemistry of the cysts found that phospho-S6 ribosomal protein, a marker of mTORC1 activity, was increased in Pkd2WS25/− mice and its phosphorylation was decreased by sirolimus treatment. Phospho-Akt at serine 473, a marker associated with mTORC2 activity, was not different between Pkd2WS25/− mice and normal littermate controls. Hence, our study found that inhibition of mTORC1 by sirolimus correlated with decreased renal cyst growth in this model of human ADPKD but had no effect on the decline in renal function.

Accidental bromine spills are common and its large industrial stores risk potential terrorist attacks. The mechanisms of bromine toxicity and effective therapeutic strategies are unknown. Our studies demonstrate that inhaled bromine causes deleterious cardiac manifestations. In this manuscript we describe mechanisms of delayed cardiac effects in the survivors of a single bromine exposure. Rats were exposed to bromine (600 ppm for 45 min) and the survivors were sacrificed at 14 or 28 days. Echocardiography, hemodynamic analysis, histology, transmission electron microscopy (TEM) and biochemical analysis of cardiac tissue were performed to assess functional, structural and molecular effects. Increases in right ventricular (RV) and left ventricular (LV) end-diastolic pressure and LV end-diastolic wall stress with increased LV fibrosis were observed. TEM images demonstrated myofibrillar loss, cytoskeletal breakdown and mitochondrial damage at both time points. Increases in cardiac troponin I (cTnI) and N-terminal pro brain natriuretic peptide (NT-proBNP) reflected myofibrillar damage and increased LV wall stress. LV shortening decreased as a function of increasing LV end-systolic wall stress and was accompanied by increased sarcoendoplasmic reticulum calcium ATPase (SERCA) inactivation and a striking dephosphorylation of phospholamban. NADPH oxidase 2 and protein phosphatase 1 were also increased. Increased circulating eosinophils and myocardial 4-hydroxynonenal content suggested increased oxidative stress as a key contributing factor to these effects. Thus, a continuous oxidative stress-induced chronic myocardial damage along with phospholamban dephosphorylation are critical for bromine-induced chronic cardiac dysfunction. These findings in our preclinical model will educate clinicians and public health personnel and provide important endpoints to evaluate therapies.

Background: Pulmonary arterial hypertension (PAH) is a progressive proliferative vasculopathy associated with mechanical and electrical changes, culminating in increased vascular resistance, right ventricular (RV) failure, and death. With a main focus on invasive tools, there has been an underutilization of echocardiography, electrocardiography, and biomarkers to non-invasively assess the changes in myocardial and pulmonary vascular structure and function during the course of PAH.Methods: A SU5416-hypoxia rat model was used for inducing PAH. Biventricular functions were measured using transthoracic two-dimensional (2D) echocardiography/Doppler (echo/Doppler) at disease onset (0 week), during progression (3 weeks), and establishment (5 weeks). Similarly, electrocardiography was performed at 0, 3, and 5 weeks. Invasive hemodynamic measurements and markers of cardiac injury in plasma were assessed at 0, 3, and 5 weeks.Results: Increased RV systolic pressure (RVSP) and rate of isovolumic pressure rise and decline were observed at 0, 3, and 5 weeks in PAH animals. EKG showed a steady increase in QT-interval with progression of PAH, whereas P-wave height and RS width were increased only during the initial stages of PAH progression. Echocardiographic markers of PAH progression and severity were also identified. Three echocardiographic patterns were observed: a steady pattern (0–5 weeks) in which echo parameter changed progressively with severity [inferior vena cava (IVC) expiratory diameter and pulmonary artery acceleration time (PAAT)], an early pattern (0–3 weeks) where there is an early change in parameters [RV fractional area change (RV-FAC), transmitral flow, left ventricle (LV) output, estimated mean PA pressure, RV performance index, and LV systolic eccentricity index], and a late pattern (3–5 weeks) in which there is only a late rise at advanced stages of PAH (LV diastolic eccentricity index). RVSP correlated with PAAT, PAAT/PA ejection times, IVC diameters, RV-FAC, tricuspid systolic excursion, LV systolic eccentricity and output, and transmitral flow. Plasma myosin light chain (Myl-3) and cardiac troponin I (cTnI) increased progressively across the three time points. Cardiac troponin T (cTnT) and fatty acid-binding protein-3 (FABP-3) were significantly elevated only at the 5-week time point.Conclusion: Distinct electrocardiographic and echocardiographic patterns along with plasma biomarkers were identified as useful non-invasive tools for monitoring PAH progression.

Background We previously demonstrated that lovastatin decreases cyst volume and improves kidney function in the Han:SPRD (Cy/+) rat model of ADPKD. Since endothelial dysfunction and inflammatory activity are evident in patients with ADPKD, we investigated whether lovastatin reduces the inflammation and vascular dysfunction and improves kidney cell energy metabolism of Cy/+ rats. Methods Cy/+ and normal littermate control animals (+/+) were treated with either lovastatin (4 mg/kg/day) or vehicle (ethanol) from 3–8 weeks of age. 1 H-NMR analysis was performed on water-soluble and lipid kidney fractions following perchloric acid extraction. Targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to assess endothelial dysfunction, oxidative stress and inflammation markers in plasma and kidney tissue extracts. Results Cy/+ rats showed perturbations in fatty acid metabolism and increased synthesis of pro-inflammatory lipoxygenases-produced bioactive lipids was observed. Lovastatin decreased inflammatory markers, specifically 13-HODE, 12-HETE and leukotriene B4. In Cy/+ rats, lovastatin reduced the elevated homocysteine and allantoin plasma levels and increased arginine, that is known to positively affect NO production. In terms of kidney cell metabolism, Cy/+ rats showed reduced Krebs cycle activity. Treatment with lovastatin increased the Krebs cycle activity as well as the glycolytical lactate production, thus improving the overall energy state of the cystic kidney. Conclusion As previously described, lovastatin was able to decrease kidney weight and cyst volume density in Cy/+ rats. The decrease in cyst volume was accompanied by a reduction in arachidonic acid-mediated inflammation markers, the normalization of metabolism of NO precursors and the improvement of kidney energy cell metabolism.

Noxious chemicals like chlorine induce extreme distress, pain, and irritation in exposed individuals, yet methods to evaluate the pain-related behavioral response are absent. It is also unknown whether analgesics would alleviate pain and physical discomfort induced by such noxious chemicals. The grimace scale (GS), which evaluates facial expression features such as orbital tightening (OT), is a valuable indicator of pain and distress in animals. However, conventional GS approaches are labor-intensive, prone to subjectivity, and lack quantitative precision. In this study, we employed machine learning with DeepLabCut to annotate key facial landmarks in video recordings of chlorine-exposed rats. Focusing on the superior and inferior eyelid margins and the medial and lateral canthi, we quantified eyelid distance and palpebral fissure width as measures of OT. Rigorous inclusion and exclusion criteria for annotated images were established to ensure accuracy and reproducibility. The quantitative GS in rats subjected to chlorine exposure was validated. Significant reductions in eyelid distance and palpebral fissure width were observed upon chlorine exposure as compared to unexposed baseline control animals. Administration of the opioid analgesic buprenorphine significantly reduced the OT caused by chlorine. This study establishes a robust, quantitative method for assessing OT in chlorine-exposed rats using DeepLabCut, providing a scalable, objective tool for assessing pain induced by noxious chemicals in preclinical research. This study also suggests that opioids can alleviate pain and physical discomfort induced by inhalation of noxious chemicals, providing a new therapeutic strategy for managing the respiratory hazard of noxious chemicals.Noxious chemicals like chlorine induce extreme distress, pain, and irritation in exposed individuals, yet methods to evaluate the pain-related behavioral response are absent. It is also unknown whether analgesics would alleviate pain and physical discomfort induced by such noxious chemicals. The grimace scale (GS), which evaluates facial expression features such as orbital tightening (OT), is a valuable indicator of pain and distress in animals. However, conventional GS approaches are labor-intensive, prone to subjectivity, and lack quantitative precision. In this study, we employed machine learning with DeepLabCut to annotate key facial landmarks in video recordings of chlorine-exposed rats. Focusing on the superior and inferior eyelid margins and the medial and lateral canthi, we quantified eyelid distance and palpebral fissure width as measures of OT. Rigorous inclusion and exclusion criteria for annotated images were established to ensure accuracy and reproducibility. The quantitative GS in rats subjected to chlorine exposure was validated. Significant reductions in eyelid distance and palpebral fissure width were observed upon chlorine exposure as compared to unexposed baseline control animals. Administration of the opioid analgesic buprenorphine significantly reduced the OT caused by chlorine. This study establishes a robust, quantitative method for assessing OT in chlorine-exposed rats using DeepLabCut, providing a scalable, objective tool for assessing pain induced by noxious chemicals in preclinical research. This study also suggests that opioids can alleviate pain and physical discomfort induced by inhalation of noxious chemicals, providing a new therapeutic strategy for managing the respiratory hazard of noxious chemicals.