Arsenic and Heavy Metals in Sediments Affected by Typical Gold Mining Areas in Southwest China: Accumulation, Sources and Ecological Risks.

Gold mining is associated with serious heavy metal pollution problems. However, the studies on such pollution caused by gold mining in specific geological environments and extraction processes remain insufficient. This study investigated the accumulation, fractions, sources and influencing factors of arsenic and heavy metals in the sediments from a gold mine area in Southwest China and also assessed their pollution and ecological risks. During gold mining, As, Sb, Zn, and Cd in the sediments were affected, and their accumulation and chemical activity were relatively high. Gold mining is the main source of As, Sb, Zn and Cd accumulation in sediments (over 40.6%). Some influential factors cannot be ignored, i.e., water transport, local lithology, proportion of mild acido-soluble fraction (F1) and pH value. In addition, arsenic and most tested heavy metals have different pollution and ecological risks, especially As and Sb. Compared with the other gold mining areas, the arsenic and the heavy metal sediments in the area of this study have higher pollution and ecological risks. The results of this study show that the local government must monitor potential environmental hazards from As and Sb pollution to prevent their adverse effects on human beings. This study also provides suggestions on water protection in the same type of gold-mining areas.

Outcome of primary intraosseous carcinoma: Case review of a single institution.

OBJECTIVE: The purpose of this study was to investigate the prognostic factors and treatment of primary intraosseous carcinoma (PIOC). METHODS: Patients diagnosed with POIC and received treatment in Sichuan Cancer Hospital from 2000 to 2019 were followed up and retrospectively reviewed. RESULTS: A total of 28 patients were included in the study, with a mean age of 60 years (60 ± 10.11). The 2-year and 5-year overall survival (OS) were 60.7% and 38.5%, respectively. In the univariate analysis, surgery combined with adjuvant therapy improved the OS compared with surgery or radiotherapy alone (p = 0.035), and patients who received postoperative adjuvant radiotherapy had a higher OS than those who received radical radiotherapy (p = 0.01). In addition, patients with well-differentiated tumors have increased progression-free survival (p = 0.01). Multivariate analyses showed that radiotherapy was an independent indicator for OS (p = 0.007). CONCLUSIONS: Surgery combined with adjuvant therapy is the superior treatment strategy for PIOC at present. This study is the first to confirm the positive role of radiotherapy in treating PIOC with data to back it up.

A personalized prediction model for urinary tract infections in type 2 diabetes mellitus using machine learning.

Patients with type 2 diabetes mellitus (T2DM) are at higher risk for urinary tract infections (UTIs), which greatly impacts their quality of life. Developing a risk prediction model to identify high-risk patients for UTIs in those with T2DM and assisting clinical decision-making can help reduce the incidence of UTIs in T2DM patients. To construct the predictive model, potential relevant variables were first selected from the reference literature, and then data was extracted from the Hospital Information System (HIS) of the Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital for analysis. The data set was split into a training set and a test set in an 8:2 ratio. To handle the data and establish risk warning models, four imputation methods, four balancing methods, three feature screening methods, and eighteen machine learning algorithms were employed. A 10-fold cross-validation technique was applied to internally validate the training set, while the bootstrap method was used for external validation in the test set. The area under the receiver operating characteristic curve (AUC) and decision curve analysis (DCA) were used to evaluate the performance of the models. The contributions of features were interpreted using the SHapley Additive ExPlanation (SHAP) approach. And a web-based prediction platform for UTIs in T2DM was constructed by Flask framework. Finally, 106 variables were identified for analysis from a total of 119 literature sources, and 1340 patients were included in the study. After comprehensive data preprocessing, a total of 48 datasets were generated, and 864 risk warning models were constructed based on various balancing methods, feature selection techniques, and a range of machine learning algorithms. The receiver operating characteristic (ROC) curves were used to assess the performances of these models, and the best model achieved an impressive AUC of 0.9789 upon external validation. Notably, the most critical factors contributing to UTIs in T2DM patients were found to be UTIs-related inflammatory markers, medication use, mainly SGLT2 inhibitors, severity of comorbidities, blood routine indicators, as well as other factors such as length of hospital stay and estimated glomerular filtration rate (eGFR). Furthermore, the SHAP method was utilized to interpret the contribution of each feature to the model. And based on the optimal predictive model a user-friendly prediction platform for UTIs in T2DM was built to assist clinicians in making clinical decisions. The machine learning model-based prediction system developed in this study exhibited favorable predictive ability and promising clinical utility. The web-based prediction platform, combined with the professional judgment of clinicians, can assist to make better clinical decisions.

Develop an ADR prediction system of Chinese herbal injections containing Panax notoginseng saponin: a nested case-control study using machine learning.

OBJECTIVE: This study aimed to develop an adverse drug reactions (ADR) antecedent prediction system using machine learning algorithms to provide the reference for security usage of Chinese herbal injections containing Panax notoginseng saponin in clinical practice. DESIGN: A nested case-control study. SETTING: National Center for ADR Monitoring and the Electronic Medical Record (EMR) system. PARTICIPANTS: All patients were from five medical institutions in Sichuan Province from January 2010 to December 2018. MAIN OUTCOMES/MEASURES: Data of patients with ADR who used Chinese herbal injections containing Panax notoginseng saponin were collected from the National Center for ADR Monitoring. A nested case-control study was used to randomly match patients without ADR from the EMR system by the ratio of 1:4. Eighteen machine learning algorithms were applied for the development of ADR prediction models. Area under curve (AUC), accuracy, precision, recall rate and F1 value were used to evaluate the predictive performance of the model. An ADR prediction system was established by the best model selected from the 1080 models. RESULTS: A total of 530 patients from five medical institutions were included, and 1080 ADR prediction models were developed. Among these models, the AUC of the best capable one was 0.9141 and the accuracy was 0.8947. According to the best model, a prediction system, which can provide early identification of patients at risk for the ADR of Panax notoginseng saponin, has been established. CONCLUSION: The prediction system developed based on the machine learning model in this study had good predictive performance and potential clinical application.

Predictive models of medication non-adherence risks of patients with T2D based on multiple machine learning algorithms.

OBJECTIVE: Medication adherence plays a key role in type 2 diabetes (T2D) care. Identifying patients with high risks of non-compliance helps individualized management, especially for China, where medical resources are relatively insufficient. However, models with good predictive capabilities have not been studied. This study aims to assess multiple machine learning algorithms and screen out a model that can be used to predict patients' non-adherence risks. METHODS: A real-world registration study was conducted at Sichuan Provincial People's Hospital from 1 April 2018 to 30 March 2019. Data of patients with T2D on demographics, disease and treatment, diet and exercise, mental status, and treatment adherence were obtained by face-to-face questionnaires. The medication possession ratio was used to evaluate patients' medication adherence status. Fourteen machine learning algorithms were applied for modeling, including Bayesian network, Neural Net, support vector machine, and so on, and balanced sampling, data imputation, binning, and methods of feature selection were evaluated by the area under the receiver operating characteristic curve (AUC). We use two-way cross-validation to ensure the accuracy of model evaluation, and we performed a posteriori test on the sample size based on the trend of AUC as the sample size increase. RESULTS: A total of 401 patients out of 630 candidates were investigated, of which 85 were evaluated as poor adherence (21.20%). A total of 16 variables were selected as potential variables for modeling, and 300 models were built based on 30 machine learning algorithms. Among these algorithms, the AUC of the best capable one was 0.866±0.082. Imputing, oversampling and larger sample size will help improve predictive ability. CONCLUSIONS: An accurate and sensitive adherence prediction model based on real-world registration data was established after evaluating data filling, balanced sampling, and so on, which may provide a technical tool for individualized diabetes care.

Platycodigenin as Potential Drug Candidate for Alzheimer's Disease via Modulating Microglial Polarization and Neurite Regeneration.

Neuroinflammatory microenvironment, regulating neurite regrowth and neuronal survival, plays a critical role in Alzheimer's disease (AD). During neuroinflammation, microglia are activated, inducing the release of inflammatory or anti-inflammatory factors depending on their polarization into classical M1 microglia or alternative M2 phenotype. Therefore, optimizing brain microenvironment by small molecule-targeted microglia polarization and promoting neurite regeneration might be a potential therapeutic strategy for AD. In this study, we found platycodigenin, a naturally occurring triterpenoid, promoted M2 polarization and inhibited M1 polarization in lipopolysaccharide (LPS)-stimulated BV2 and primary microglia. Platycodigenin downregulated pro-inflammatory molecules such as interleukin (IL)-1ß, tumor necrosis factor (TNF)-α, IL-6 and nitric oxide (NO), while upregulated anti-inflammatory cytokine IL-10. Further investigation confirmed that platycodigenin inhibited cyclooxygenase-2 (Cox2) positive M1 but increased Ym1/2 positive M2 microglial polarization in primary microglia. In addition, platycodigenin significantly decreased LPS-induced the hyperphosphorylation of mitogen-activated protein kinase (MAPK) p38 and nuclear factor-κB (NF-κB) p65 subunits. Furthermore, the inactivation of peroxisome proliferators-activated receptor γ (PPARγ) induced by LPS was completely ameliorated by platycodigenin. Platycodigenin also promoted neurite regeneration and neuronal survival after Aß treatment in primary cortical neurons. Taken together, our study for the first time clarified that platycodigenin effectively ameliorated LPS-induced inflammation and Aß-induced neurite atrophy and neuronal death.

Neuroprotective activity of two active chemical constituents from Tinospora hainanensis.

OBJECTIVE: To determine the chemical structure of the new compound and investigate the protective effects of Tinosporaic acid A and B towards in-vitro neuro. METHODS: The structures of two new compounds were established by analyzing its 1D and 2D NMR spectra as well as HRESIMS. Their neuroprotective effects with respect to the antioxidant properties were evaluated by radical scavenging tests and hydrogen peroxide-injured oxidative stress model in PC12 cell lines. Cell morphology of treated PC12 cells was observed by phase contrast microscopy. In-vitro MTT assay, lactate dehydrogenase activity assay and oxidative stress markers (intracellular ROS production, MDA level, and caspase-3 activity) were used to evaluate the protective effects against hydrogen peroxide induced cytotoxicity in PC12 cells. RESULTS: The two new compounds, named Tinosporaic acid A and B, were isolated and identified from the stem bark of Tinospora hainanensis. Cell viability studies identified a representative concentration for each extract that was subsequently used to measure oxidative stress markers. Both extracts were able to reverse the oxidative damage caused by hydrogen peroxide, thus promoting PC12 cells survival. The concentration of Tinosporaic acid A and B were 86.34 µg/mL and 22.06 µg/mL respectively, which is neuroprotective for EC50. The results indicated that both of them significantly attenuated hydrogen peroxide-induced neurotoxicity. CONCLUSION: The two new compounds isolated from ethanol extracts of Tinospora hainanensis are the promising natural ones with neuroprotective activity and needed for further research.

[Investigation on an outbreak of trichinosis and clinical analysis].

An outbreak of trichinosis occurred in Lhingchi Prefecture of Tibet with 9 cases identified among 10 people. They consumed collectively raw or undercooked pork. Two cases died because of misdiagnosis and mistreatment. In the 9 cases, 3 had eosinophilia, 3 showed positive anti-Trichinella IgG. Trichinella larvae were found in gastrocnemius muscle of 3 cases by biopsy including the 2 died cases.Seven cases were successfully treated with albendazole.

Proteasome inhibitor attenuates skeletal muscle reperfusion injury by blocking the pathway of nuclear factor-kappaB activation.

BACKGROUND: Nuclear factor-kappaB is a key transcriptional factor in the regulation of inflammatory factors that are involved in tissue reperfusion injury, but conflicting data have been presented in the literature. The proteasome regulates proteins that control cell-cycle progression and apoptosis, and inhibition of the proteasome has been shown to reduce nuclear factor-kappaB activation and reperfusion injury. Although bortezomib is a potent proteasome inhibitor, its role in skeletal muscle reperfusion injury has not been documented, and its effects on the regulation of inflammatory factors in reperfused tissue are unclear. In this study, the authors investigated the role of nuclear factor-kappaB in skeletal muscle reperfusion injury and the effect of bortezomib (a proteasome inhibitor) on reperfusion injury. METHODS: Pedicled cremaster muscle flaps from bortezomib-treated and phosphate-buffered saline-treated control mice were subjected to 4.5 hours of ischemia and 90 minutes of reperfusion. RESULTS: During reperfusion, arterial diameters and blood flow recovered earlier and more completely in bortezomib-treated muscle than in controls. Compared with controls, Western blot analysis demonstrated a significant reduction in degradation of nuclear factor-kappaB inhibitory protein and expression of inducible nitric oxide synthase protein in bortezomib-treated muscle at the end of reperfusion. Immunohistochemistry showed decreased nuclear factor-kappaB p65-binding activity and down-regulated protein expression of intercellular adhesion molecule-1 and nitrotyrosine, accompanied by less muscle edema and inflammation as proven by histologic examination. CONCLUSIONS: Bortezomib effectively blocks nuclear factor-kappaB activation in attenuating muscle reperfusion injury through inhibiting nuclear factor-kappaB inhibitory protein degradation. Therefore, inhibition of proteasome activity may provide a novel therapeutic strategy for the treatment of skeletal muscle reperfusion injury.

Intermittent pneumatic compression regulates expression of nitric oxide synthases in skeletal muscles.

This study investigated the effects of intermittent pneumatic compression (IPC) on expression of nitric oxide synthase (NOS) isoforms in compressed (anterior tibialis, AT) and uncompressed (cremaster muscles, CM) skeletal muscles. Following IPC application of 0.5, 1, and 5h on both legs of rats, the endothelial NOS (eNOS) mRNA expression was significantly up-regulated to 1.2-, 1.8, and 2.7-fold from normal, respectively, in both AT and CM, and protein expression increased more than 1.5-fold of normal at each time point. Similarly, neuronal NOS expression was up-regulated, but to a lesser degree. In contrast, inducible NOS expression was significantly and time-dependently down-regulated in both muscles. After IPC cessation, eNOS levels returned to normal in both AT and CM. The results confirm our hypothesis that IPC-induced vasodilation is mediated by regulating expression of NOS isoforms, in particular eNOS, in both compressed and uncompressed skeletal muscles. The results also suggest the importance of precisely characterizing expression of each NOS isoform in tissue pathophysiology.

Inhibition of iNOS attenuates skeletal muscle reperfusion injury in extracellular superoxide dismutase knockout mice.

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are closely involved in the mechanism of skeletal muscle ischemia/reperfusion (I/R) injury. This study was designed to determine the effects of inducible nitric oxide synthase (iNOS) inhibitor 1400 W on the reperfused cremaster muscle in extracellular super-oxide dismutase knockout (EC-SOD(-/-)) mice. The muscle was exposed to 4.5 h of ischemia, followed by 90 min of reperfusion. Mice received either 3 mg/kg of 1400 W or the same amount of phosphate-buffered saline (PBS, as a control) subcutaneously at 10 min before the start of reperfusion. 1400 W treatment markedly improved the recovery speed of vessel diameter and blood flow in the reperfused cremaster muscle of EC-SOD(-/-) mice compared to controls. Histological examination showed reduced edema in the interstitial space and muscle fiber, and reduced density of nitrotyrosine (a marker of total peroxi-nitrate (ONOO(-)) level) in 1400 W-treated muscles compared to controls. Our results suggest that iNOS and ONOO(-) products are involved in skeletal muscle I/R injury. Reduced I/R injury by using selective inhibition of iNOS perhaps works by limiting cytotoxic ONOO(-) generation, a reaction product of nitric oxide (NO) and super-oxide anion (O(2) (-)). Thus, inhibition of iNOS appears to be a treatment strategy for reducing clinical I/R injury.

Inhibition of inducible nitric oxide synthase promotes recovery of motor function in rats after sciatic nerve ischemia and reperfusion.

PURPOSE: To investigate the effects of inhibition of inducible nitric oxide synthase (iNOS) on the recovery of motor function in the rat sciatic nerve after ischemia and reperfusion injury. METHODS: A 10-mm segment of the sciatic nerve from 169 rats had 2 hours of ischemia followed by up to 42 days of reperfusion. The animals were divided into 2 groups that received either iNOS inhibitor 1400W or the same volume of sterile water subcutaneously. A walking track test was used to evaluate the motor functional recovery during reperfusion. Statistical analysis was performed for the measurements of the sciatic functional index (SFI) by using 2-way analysis of variance; 1-way analysis of variance was used for the post hoc analysis of specific values at each time point of the SFI measurement. RESULTS: 1400W-treated rats had earlier motor functional recovery than controls, with a significantly improved SFI between days 11 and 28. Histology showed less axonal degeneration and earlier regeneration of nerve fibers in the 1400W group than in the controls. Inducible NOS messenger RNA and protein were up-regulated during the first 3 days of reperfusion but there was a down-regulation of neuronal NOS and up-regulation of endothelial NOS in control animals. 1400W treatment attenuated the increase of iNOS but had no effect on neuronal NOS and endothelial NOS. CONCLUSIONS: Our results indicate that early inhibition of iNOS appears to be critical for reducing or preventing ischemia and reperfusion injury.

The effects of exogenous nitric oxide donor on motor functional recovery of reperfused peripheral nerve.

PURPOSE: To investigate the effects of the nitric oxide donor S-nitroso-N-acetylcysteine (SNAC) on motor functional recovery of reperfused rat sciatic nerve. METHODS: Seventy-eight rats were divided into groups treated with SNAC (100 nmol/100 g/min), methylprednisolone 30 mg/kg/h for 15 minutes, 45-minute pause, 5.4 mg/kg/h for 1.5 h), and phosphate-buffered saline 0.2 mL/100 g/h). A 1-cm segment of sciatic nerve had 2 hours of ischemia and the results were evaluated after various reperfusion periods using a walking track test, muscle contractile testing, muscle weight, and histology. RESULTS: During reperfusion there was a significant overall improvement in sciatic functional index measurement and isometric titanic contractile force for the SNAC-treated group compared with the methylprednisolone- and phosphate-buffered saline- treated groups. The SNAC group had significantly earlier improvement in the sciatic functional index measurement between days 7 and 28. Restoration of the contractile force and muscle weight of the extensor digitorum longus muscle began earlier in the SNAC group--after day 11--whereas the other 2 groups showed progressive atrophy until day 21, with a significant difference between the SNAC group and the other 2 groups. Histologic examination showed that SNAC-treated rats had less severe degeneration and earlier regeneration of axons than the others. Although methylprednisolone-treated rats showed earlier recovery than phosphate-buffered saline-treated rats in all parameters there were no significant differences between these 2 groups. CONCLUSIONS: Supplementation of nitric oxide is effective in promoting motor functional recovery of the reperfused peripheral nerve and has potential to replace or augment steroids as therapeutic agents in treatment of nervous system ischemia/reperfusion injury.

Addition of nitric oxide donor S-nitroso-N-acetylcysteine to selective iNOS inhibitor 1400W further improves contractile function in reperfused skeletal muscle.

This study examines the effects of combination therapy with the nitric oxide (NO) donor S-nitroso-N-acetylcysteine (SNAC) and the iNOS inhibitor N-(3-(aminomethyl)benzyl) acetamidine (1400W) on contractile function in reperfused rat skeletal muscle. The right extensor digitorum longus (EDL) muscles of 104 rats were subjected to 3 h of ischemia followed by reperfusion times of 3 h, 24 h, and 7 days. For each time period, rats were further divided into sham operation, control, 1400W only, and 1400W plus SNAC groups. In vitro muscle contractile functional testing was performed in an organ chamber with electrical stimulation. The results showed that twitch and isometric tetanic forces were significantly improved in the 1400W-alone group compared to controls for 24 h and 7 days, but not 3 h of reperfusion. However, all three time periods of reperfusion showed that combination treatment of 1400W + SNAC significantly improved muscle contractile force compared to both control and 1400W-only groups. This corresponded to the decreased tissue necrosis and inflammation seen with combination therapy histologically. Our results demonstrate that combination treatment of 1400W + SNAC promotes functional recovery in reperfused skeletal muscle, supporting that manipulation of NO levels with a NO donor and an iNOS inhibitor is more beneficial than either treatment in isolation.

Skeletal muscle reperfusion injury is enhanced in extracellular superoxide dismutase knockout mouse.

This study investigates the role of extracellular SOD (EC-SOD), the major extracellular antioxidant enzyme, in skeletal muscle ischemia and reperfusion (I/R) injury. Pedicled cremaster muscle flaps from homozygous EC-SOD knockout (EC-SOD-/-) and wild-type (WT) mice were subjected to 4.5-h ischemia and 90-min reperfusion followed by functional and molecular analyses. Our results revealed that EC-SOD-/- mice showed significantly profound I/R injury compared with WT littermates. In particular, there was a delayed and incomplete recovery of arterial spasm and blood flow during reperfusion, and more severe acute inflammatory reaction and muscle damage were noted in EC-SOD-/- mice. After 90-min reperfusion, intracellular SOD [copper- and zinc-containing SOD (CuZn-SOD) and manganese-containing (Mn-SOD)] mRNA levels decreased similarly in both groups. EC-SOD mRNA levels increased in WT mice, whereas EC-SOD mRNA was undetectable, as expected, in EC-SOD-/- mice. In both groups of animals, CuZn-SOD protein levels decreased and Mn-SOD protein levels remained unchanged. EC-SOD protein levels decreased in WT mice. Histological analysis showed diffuse edema and inflammation around muscle fibers, which was more pronounced in EC-SOD-/- mice. In conclusion, our data suggest that EC-SOD plays an important role in the protection from skeletal muscle I/R injury caused by excessive generation of reactive oxygen species.

Reverse end-to-side neurotization.

The authors describe a reverse end-to-side neurorrhaphy model in which the proximal end of a donor nerve is sutured to an epineurial window in the side of a recipient nerve. If effective, this technique would have useful applications in nerve reconstructive surgery. Female Sprague-Dawley rats were divided into three groups (n = 9). In Group A, the peroneal nerve was transected and directly repaired in standard end-to-end fashion. In Group B, the tibial nerve was transected and the proximal end was sutured to the side of the intact peroneal nerve through an epineurial window. In Group C, the tibial nerve was also transected and the proximal end sutured to the side of the intact peroneal nerve, but the peroneal nerve was then cut proximally. After 12 weeks, contractile forces of the extensor digitorum communis (EDC) were measured, following stimulation of the proximal sciatic nerve on all experimental (and normal) hind limbs. For Group B, the peroneal nerve was transected proximal to the repair site just prior to stimulation. Group B animals did not demonstrate any measurable contractions. No statistically significant differences were found between Groups A and C. This demonstrated the successful neurotization of a denervated muscle using a reverse end-to-side neurorrhaphy model.

The effects of N(omega)-propyl-L-arginine on reperfusion injury of skeletal muscle.

N(omega)-Propyl-L-arginine (NPA) is reported to be a highly selective inhibitor of neuronal nitric oxide synthase (nNOS). This in vivo study observed its role in ischemia/reperfusion (I/R) injury in rat skeletal muscle. Our results showed that NPA infusion significantly increased vessel diameters and blood flow in reperfused cremaster muscle, and slightly increased contractile function in reperfused extensor digitorum longus (EDL) muscle. In addition, NPA treatment slightly increased I/R-mediated downregulation of nNOS and eNOS mRNA and protein levels. Although NPA showed a beneficial role in I/R injury, our in vivo data do not support NPA as a selective nNOS inhibitor. Also, our data do not provide any insight into the mechanism of NPA. Thus, the in vivo mechanism of action of NPA needs to be further identified, and the role of nNOS in skeletal muscle I/R still remains to be determined.

Inhibition of iNOS with 1400W improves contractile function and alters nos gene and protein expression in reperfused skeletal muscle.

This study examined the effects of 1400W, an inhibitor of inducible nitric oxide (iNOS), on contractile function and iNOS expression in reperfused skeletal muscle. The right extensor digitorum longus (EDL) muscle of 104 rats underwent a sham operation or 3-h ischemia followed by 3-h or 24-h reperfusion (I/R). Rats received 3 mg/kg 1400W, 10 mg/kg 1400W, or water subcutaneously. Results showed that EDL contractile function in both 1400W-treated groups significantly outperformed the controls at 24-h but not at 3-h reperfusion. Although iNOS expression increased in all three I/R groups during reperfusion, a significantly smaller increase was found in 1400W-treated muscles after 3-h reperfusion, and more dramatically so after 24-h reperfusion. Our results indicate that inhibition of iNOS preserved the contractile function in reperfused skeletal muscle, perhaps via downregulating iNOS expression. Protection by 1400W at 24-h reperfusion suggests that the role of iNOS in exaggerating reperfusion injury is more prominent in the later stages of injury.

NF-kappaB p65 involves in reperfusion injury and iNOS gene regulation in skeletal muscle.

This study investigated the effects of inhibition of NF-kappaB activation on microcirculation and inducible NOS expression in reperfused rat cremaster muscle. The muscle from 16 rats underwent 5-h ischemia and 90-min reperfusion. Each rat received NF-kappaB inhibitor pyrrolidine dithiocarbamate (PDTC, 150 mg/kg) or phosphate-buffered saline 15 min before reperfusion. Results showed that PDTC treatment had a significant overall increase in muscle blood flow during reperfusion. Blood flow more rapidly recovered to and over baseline in the PDTC-treated group than in controls, with a significant difference at 10-30 min and 70-90 min. Expression of iNOS mRNA had a 167-fold increase from normal in controls, but was significantly (P < 0.05) reduced to a 63-fold increase in PDTC-treated muscles. In addition, PDTC treatment significantly (P < 0.05) decreased a reperfusion-induced increase in activated NF-kappaB p65 and nuclear p65 protein. Our results suggest that NF-kappaB is involved in I/R injury and that inhibition of NF-kappaB p65 activation affords protection against I/R injury, perhaps via downregulating expression of iNOS transcription.

Nitric oxide involvement in reperfusion injury of denervated muscle.

PURPOSE: To investigate whether inhibition of inducible nitric oxide synthase (iNOS) improves microcirculation in denervated and reperfused skeletal muscle. METHODS: The cremaster muscles of 52 rats received iNOS inhibitor 1400W (3 mg/kg) or phosphate buffered saline (PBS) and underwent either 3 hours of ischemia and 1.5 hours of reperfusion or a sham operation. During reperfusion the vessel diameters were measured by using intravital videomicroscopy and overall muscle blood flow was measured with laser Doppler flowmetry. The expression of NOS messenger RNA (mRNA) and protein was determined by using real-time reverse-transcription polymerase chain reaction and Western blot, respectively. RESULTS: 1400W treatment significantly increased the mean blood flow of the reperfused muscle compared with controls, and this was associated with significantly less vasospasm in 10 to 20 microm, 21 to 40 microm, and 41 to 70 microm arterioles. The expression of iNOS mRNA and protein in controls increased 23-fold and 6-fold from normal, respectively, but was reduced to only a 2-fold increase in the 1400W-treated muscles. The ischemia/reperfusion (I/R)-induced decrease of endothelial NOS (eNOS) and neuronal NOS (nNOS) expression in controls was not significantly changed after 1400W treatment. CONCLUSIONS: Our data support a nitric oxide-mediated mechanism in reperfusion injury and show the importance of inhibition of iNOS in reducing reperfusion injury in denervated skeletal muscle. Our results suggest potential benefits via inhibition of iNOS to improve clinical outcomes not only for hand surgeons who work in the microsurgery field, but also for other physicians whose work involves ischemia/reperfusion injury.