A General Molecular Structural Design for Highly Efficient Photopyroptosis that can be Activated within 10 s Irradiation.

Photopyroptosis is an emerging research branch of photodynamic therapy (PDT), whereas there remains a lack of molecular structural principles to fabricate photosensitizers for triggering a highly efficient pyroptosis. Herein, a general and rational structural design principle to implement this hypothesis, is proposed. The principle relies on the clamping of cationic moieties (e.g., pyridinium, imidazolium) onto one photosensitive core to facilitate a considerable mitochondrial targeting (both of the inner and the outer membranes) of the molecules, thus maximizing the photogenerated reactive oxygen species (ROS) at the specific site to trigger the gasdermin E-mediated pyroptosis. Through this design, the pyroptotic trigger can be achieved in a minimum of 10 s of irradiation with a substantially low light dosage (0.4 J cm⁻2), compared to relevant work reported (up to 60 J cm⁻2). Moreover, immunotherapy with high tumor inhibition efficiency is realized by applying the synthetic molecules alone. This structural paradigm is valuable for deepening the understanding of PDT (especially the mitochondrial-targeted PDT) from the perspective of pyroptosis, toward the future development of the state-of-the-art form of PDT.

Linking preoperative and early intensive care unit data for prolonged intubation prediction.

Objectives: Prolonged intubation (PI) is a frequently encountered severe complication among patients following cardiac surgery (CS). Solely concentrating on preoperative data, devoid of sufficient consideration for the ongoing impact of surgical, anesthetic, and cardiopulmonary bypass procedures on subsequent respiratory system function, could potentially compromise the predictive accuracy of disease prognosis. In response to this challenge, we formulated and externally validated an intelligible prediction model tailored for CS patients, leveraging both preoperative information and early intensive care unit (ICU) data to facilitate early prophylaxis for PI. Methods: We conducted a retrospective cohort study, analyzing adult patients who underwent CS and utilizing data from two publicly available ICU databases, namely, the Medical Information Mart for Intensive Care and the eICU Collaborative Research Database. PI was defined as necessitating intubation for over 24 h. The predictive model was constructed using multivariable logistic regression. External validation of the model's predictive performance was conducted, and the findings were elucidated through visualization techniques. Results: The incidence rates of PI in the training, testing, and external validation cohorts were 11.8%, 12.1%, and 17.5%, respectively. We identified 11 predictive factors associated with PI following CS: plateau pressure [odds ratio (OR), 1.133; 95% confidence interval (CI), 1.111-1.157], lactate level (OR, 1.131; 95% CI, 1.067-1.2), Charlson Comorbidity Index (OR, 1.166; 95% CI, 1.115-1.219), Sequential Organ Failure Assessment score (OR, 1.096; 95% CI, 1.061-1.132), central venous pressure (OR, 1.052; 95% CI, 1.033-1.073), anion gap (OR, 1.075; 95% CI, 1.043-1.107), positive end-expiratory pressure (OR, 1.087; 95% CI, 1.047-1.129), vasopressor usage (OR, 1.521; 95% CI, 1.23-1.879), Visual Analog Scale score (OR, 0.928; 95% CI, 0.893-0.964), pH value (OR, 0.757; 95% CI, 0.629-0.913), and blood urea nitrogen level (OR, 1.011; 95% CI, 1.003-1.02). The model exhibited an area under the receiver operating characteristic curve (AUROC) of 0.853 (95% CI, 0.840-0.865) in the training cohort, 0.867 (95% CI, 0.853-0.882) in the testing cohort, and 0.704 (95% CI, 0.679-0.727) in the external validation cohort. Conclusions: Through multicenter internal and external validation, our model, which integrates early ICU data and preoperative information, exhibited outstanding discriminative capability. This integration allows for the accurate assessment of PI risk in the initial phases following CS, facilitating timely interventions to mitigate adverse outcomes.

Conditional survival analysis and dynamic prediction of long-term survival in Merkel cell carcinoma patients.

Background: Merkel cell carcinoma (MCC) is a rare type of invasive neuroendocrine skin malignancy with high mortality. However, with years of follow-up, what is the actual survival rate and how can we continually assess an individual's prognosis? The purpose of this study was to estimate conditional survival (CS) for MCC patients and establish a novel CS-based nomogram model. Methods: This study collected MCC patients from the Surveillance, Epidemiology, and End Results (SEER) database and divided these patients into training and validation groups at the ratio of 7:3. CS refers to the probability of survival for a specific timeframe (y years), based on the patient's survival after the initial diagnosis (x years). Then, we attempted to describe the CS pattern of MCCs. The Least absolute shrinkage and selection operator (LASSO) regression was employed to screen predictive factors. The Multivariate Cox regression analysis was applied to demonstrate these predictors' effect on overall survival and establish a novel CS-based nomogram. Results: A total of 3,843 MCC patients were extracted from the SEER database. Analysis of the CS revealed that the 7-year survival rate of MCC patients progressively increased with each subsequent year of survival. The rates progressed from an initial 41-50%, 61, 70, 78, 85%, and finally to 93%. And the improvement of survival rate was nonlinear. The LASSO regression identified five predictors including patient age, sex, AJCC stage, surgery and radiotherapy as predictors for CS-nomogram development. And this novel survival prediction model was successfully validated with good predictive performance. Conclusion: CS of MCC patients was dynamic and increased with time since the initial diagnosis. Our newly established CS-based nomogram can provide a dynamic estimate of survival, which has implications for follow-up guidelines and survivorship planning, enabling clinicians to guide treatment for these patients better.

Ablative fractional CO2 laser surgery improving sleep quality, pain and pruritus in adult hypertrophic scar patients: a prospective cohort study.

BACKGROUND: Poor sleep quality is associated with a decrease in quality of life in patients with major burn scars, combined with pruritus and pain. Few interventions have been reported to improve the sleep quality of patients with scars. In the current prospective cohort study, we investigated the efficacy of CO2-ablative fractional laser (AFL) surgery vs conventional surgery in post-burn patients with hypertrophic scars with sleep quality as the primary study outcome. METHODS: In total 68 consecutive patients undergoing scar surgical treatment were recruited, including a CO2-AFL surgery cohort (n = 35) and a conventional surgery cohort (n = 33). A subgroup from the AFL cohort was selected. Sleep quality, pain and pruritus were evaluated. Multiple linear regression analyses were performed to reveal the effect of CO2-AFL surgery. RESULTS: The CO2-AFL surgery cohort had significantly lower Pittsburgh sleep quality index (PSQI) global scores than the conventional surgery cohort after the last surgical treatment. In the subgroup of patients receiving hardware sleep monitoring, CO2-AFL markedly increased deep sleep time, deep sleep efficiency and reduced initial sleep latency. Compared to the conventional surgery cohort, the CO2-AFL cohort presented significantly lower pain and pruritus scores. Correlation analysis showed pain and pruritus were significantly associated with PSQI scores, and there were also significant correlations between pain and pruritus scores. Multiple linear regression analysis showed that surgery method was negatively linearly correlated with visual analog scale (VAS) pain score, brief pain inventory (BPI) total, VAS pruritus score, 5-D itch scale total, four-item itch questionnaire (FIIQ) total and PSQI total. CONCLUSIONS: CO2-AFL surgery significantly improved sleep quality and reduced pain and pruritus of hypertrophic scar patients. The alleviation of sleep disorder was associated with improvement of deep sleep quality including deep sleep time and deep sleep deficiency. TRIAL REGISTRATION: The Chinese Clinical Trial Registry (ChiCTR200035268) approved retrospectively registration on 5 May 2020.

Xihuang pill potentiates the anti-tumor effects of temozolomide in glioblastoma xenografts through the Akt/mTOR-dependent pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Xihuang pill, as a famous traditional Chinese medicine formula, is used for tumor treatment in China. The anti-tumor activities and mechanisms of Xihuang pill still remain unclear. AIM OF THE STUDY: The Akt/mTOR signaling pathway plays an important role in mediating cell proliferation and apoptosis in glioblastoma. This study aimed to investigate whether Xihuang pill could potentiate temozolomide-induced apoptosis of glioblastoma U87 and U251 cells in vivo and its underlying mechanisms related to Akt/mTOR pathway. MATERIALS AND METHODS: Human glioblastoma U87 and U251 xenograft models were established. Immunocytochemistry and Western blot were performed to evaluate the anti-proliferative effect, apoptosis and Akt/mTOR signaling mediators. RESULTS: The results showed that Xihuang pill (0.5, 1 g/kg) or temozolomide (10 mg/kg) treatment alone inhibited tumor growth in glioblastoma U87 and U251 xenografts. When Xihuang pill (1 g/kg) and temozolomide (10 mg/kg) were co-administrated, the activities of antitumor growth were markedly increased. Meanwhile, Xihuang pill (0.5, 1 g/kg) or temozolomide (10 mg/kg) treatment alone decreased the levels of Ki67 and PCNA expression in glioblastoma U87 and U251 xenografts. In combination treatment group, the inhibitory effects on Ki67 and PCNA expression were significantly enhanced in glioblastoma U87 and U251 xenografts compared to temozolomide treatment alone. Examining the apoptotic index by TUNEL assay showed similar results. Furthermore, Xihuang pill markedly down-regulated the Bcl-2/Bax ratio and inhibited the activation of Akt/mTOR pathway in glioblastoma U87 and U251 xenografts. In addition, no significant signs of toxicities were related to Xihuang pill and/or temozolomide treatment. CONCLUSIONS: The present study suggested that Xihuang pill might potentiate temozolomide-induced apoptosis of glioblastoma cells in vivo through inhibiting Akt/mTOR-dependent pathway.

One-step approach for full-thickness skin defect reconstruction in rats using minced split-thickness skin grafts with Pelnac overlay.

BACKGROUND: Split-thickness skin grafting is the current gold standard for the treatment of traumatic skin loss. However, for patients with extensive burns, split-thickness skin grafting is limited by donor skin availability. Grafting split-thickness skin minced into micrografts increases the expansion ratio but may reduce wound repair quality. Dermal substitutes such as Pelnac can enhance the healing of full-thickness skin wounds, but their application currently requires two surgeries. The present study investigated whether it is possible to repair full-thickness skin defects and improve wound healing quality in a single surgery using Pelnac as an overlay of minced split-thickness skin grafts in a rat model. METHODS: A full-thickness skin defect model was established using male Sprague-Dawley rats of 10 weeks old. The animals were randomly divided into control and experimental groups in which Vaseline gauze and Pelnac, respectively, were overlaid on minced split-thickness skin grafts to repair the defects. Wound healing rate and quality were compared between the two groups. For better illustration of the quality of wound healing, some results were compared with those obtained for normal skin of rats. RESULTS: We found that using Pelnac as an overlay for minced split-thickness skin grafts accelerated wound closure and stimulated cell proliferation and tissue angiogenesis. In addition, this approach enhanced collagen synthesis and increased the formation of basement membrane and dermis as well as the expression of growth factors related to wound healing while reducing scar formation. CONCLUSIONS: Using minced split-thickness skin grafts overlaid with Pelnac enables the reconstruction of full-thickness skin defects in a single step and can increase the healing rate while improving the quality of wound healing.

Knockdown of Burton's tyrosine kinase confers potent protection against sepsis-induced acute lung injury.

Sepsis is a common and critical complication in surgical patients that often leads to multiple organ failure syndrome (MOFS), including acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Despite intensive supportive care and treatment modalities, the mortality of these patients remains high. In this study, we investigated the role of Burton's tyrosine kinase (BTK), a member of the Btk/Tec family of cytoplasmic tyrosine kinases, in the pathogenesis of sepsis, and evaluated the protective effect of in vivo Btk RNA interference in a mouse model of cecal ligation and puncture (CLP)-induced sepsis. After intratracheal injection of Btk siRNA, the mice were then subjected to CLP to induce sepsis. The results demonstrated that this approach conferred potent protection against sepsis-induced ALI, as evidenced by a significant reduction in pathological scores, epithelial cell apoptosis, pulmonary edema, vascular permeability, and the expression of inflammatory cytokines and neutrophil infiltration in the lung tissues of septic mice. In addition, RNA interference of Btk significantly suppressed p-38 and iNOS signaling pathways in transduced alveolar macrophages in vitro. These results identify a novel role for BTK in lethal sepsis and provide a potential new therapeutic approach to sepsis and ALI.

Application of flexible bronchoscopy in inhalation lung injury.

BACKGROUND: As acute inhalational injury is an uncommon presentation to most institutions, a standard approach to its assessment and management, especially using flexible bronchoscopy, has not received significant attention. METHODS: The objective of this study is to evaluate the value of using flexible bronchoscopy as part of the evaluation and management of patients with inhalational lung injury. Twenty-three cases of inhalational lung injury were treated in our three hospitals after a fire in a residential building. The twenty cases that underwent bronchoscopy as part of their management are included in this analysis. After admission, the first bronchoscopy was conducted within 18-72 hours post inhalational injury. G2-level patients were reexamined 24 hours after the first bronchoscopy, while G1-level patients were reexamined 72 hours later. Subsequently, all patients were re-examined every 2-3 days until recovered or until only tunica mucosa bronchi congestion was identified by bronchoscopy. RESULTS: Twenty patients had airway injury diagnosed by bronchoscopy including burns to the larynx and glottis or large airways. Bronchoscopic classification of the inhalation injury was performed, identifying 12 cases of grade G1 changes and 8 cases of grade G2. The airway injury in the 12 cases of grade G1 patients demonstrated recovery in 2-8 days, in the airway injury of the 8 cases of grade G2 patients had a prolonged recovery with airway injury improving in 6-21 days averaged. The difference in recovery time between the two groups was significant (P <0.05). CONCLUSIONS: The use of flexible bronchoscopy has great value in the diagnosis of inhalational injury without any complications. Its use should be incorporated into clinical practice. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1476676925108926.

Macrophage migration inhibitory factor counter-regulates dexamethasone-induced annexin 1 expression and influences the release of eicosanoids in murine macrophages.

Macrophage migration inhibitory factor (MIF), a pro-inflammatory cytokine and glucocorticoid (GC) counter-regulator, has emerged as an important modulator of inflammatory responses. However, the molecular mechanisms of MIF counter-regulation of GC still remain incomplete. In the present study, we investigated whether MIF mediated the counter-regulation of the anti-inflammatory effect of GC by affecting annexin 1 in RAW 264.7 macrophages. We found that stimulation of RAW 264.7 macrophages with lipopolysaccharide (LPS) resulted in down-regulation of annexin 1, while GC dexamethasone (Dex) or Dex plus LPS led to significant up-regulation of annexin 1 expression. RNA interference-mediated knockdown of intracellular MIF increased annexin 1 expression with or without incubation of Dex, whereas Dex-induced annexin 1 expression was counter-regulated by the exogenous application of recombinant MIF. Moreover, recombinant MIF counter-regulated, in a dose-dependent manner, inhibition of cytosolic phospholipase A2α (cPLA2α) activation and prostaglandin E2 (PGE2 ) and leukotriene B4 (LTB4 ) release by Dex in RAW 264.7 macrophages stimulated with LPS. Endogenous depletion of MIF enhanced the effects of Dex, reflected by further decease of cPLA2α expression and lower PGE2 and LTB4 release in RAW 264.7 macrophages. Based on these data, we suggest that MIF counter-regulates Dex-induced annexin 1 expression, further influencing the activation of cPLA2α and the release of eicosanoids. These findings will add new insights into the mechanisms of MIF counter-regulation of GC.

Role of inhibition of p38 mitogen-activated protein kinase in liver dysfunction after hemorrhagic shock and resuscitation.

BACKGROUND: The liver is one of the organs most frequently affected by trauma and hemorrhagic shock; the exact role of p38 mitogen-activated protein kinase (MAPK) activation in response to hepatic hemorrhagic shock/resuscitation (HS/R) remains unclear. MATERIALS AND METHODS: C57Bl/6 mice were divided into four groups: sham-operated group, SB-only group, control group, and SB + HS/R group. Hepatocellular injury (aspartate aminotransferase [AST] and alanine aminotransferase [ALT]) and tumor necrosis factor (TNF-α) and interleukin (IL-1ß) messenger ribonucleic acid (mRNA) expression in the liver were assessed 6 h after resuscitation, p38 MAPK activation in the liver was assessed at 30 min after resuscitation. RESULTS: p38 MAPK activation was higher in the control group than other groups 30 min after resuscitation. p38 MAPK activation level in the SB + HS/R group did not change significantly compared with that of sham and SB-only groups, but was significantly lower than that in the control group. The TNF-α mRNA expression in the control group was significantly higher than that in the sham group. The TNF-α mRNA levels after HS/R in the SB + HS/R group were significantly lower than those in the control group and were roughly the same as those in the sham and SB-only groups. IL-1ß mRNA expression showed similar changes in the four groups. Serum ALT and AST levels in the control group were significantly higher than those in the sham group. The increase in serum ALT and AST levels after HS/R in the SB + HS/R group was significantly less pronounced than that in the control group and markedly higher than that in the sham group. CONCLUSIONS: p38 MAPK was phosphorylated during the HS/R process. Inhibiting the activation of p38 MAPK may attenuate HS/R injury to the liver.

An epidermal stem cells niche microenvironment created by engineered human amniotic membrane.

How to amplify epidermal stem cells (ESCs) rapidly is a challenging crux in skin tissue engineering research. The present study describes the preparation of 3D micronized (300-600 µm) amniotic membrane (mAM) by means of repeated freeze-thawing cycles to deplete cell components and homogenized with a macrohomogenizer in liquid nitrogen. This newly prepared mAM not only possessed the characteristics of a microcarrier but completely retained the basement membrane structure and abundant active substances such as NGF, HGF, KGF, bFGF, TGF-ß1 and EGF in the AM matrix. The result showed that mAM combined with rotary cell culture system (RCCS) was able to amplify ESCs quickly. The relative cell viability at day 7 and 14 was significantly higher than that of the conventional 2D plate culture (326 ± 28% and 535 ± 47% versus 232 ± 21% and 307 ± 32%, P < 0.05). In addition, the new method was able to prevent cell differentiation effectively and retain the characteristics of stem cells. When mAM loaded with ESCs (ESC-mAM) was further transplanted to full-thickness skin defects in nude mice, ESCs survived well and formed a new epidermis. Four weeks after transplantation, papilla-like structures were observed, and collagen fibers were well and regularly arranged in the newly formed dermal layer. In conclusion, the mAM as a novel natural microcarrier possesses an intact basement membrane structure and bioactivities. It not only provides the microenvironment similar to the stem cell niche within the human body favorable for ex vivo culture and amplification of ESCs but can be used as the dermal scaffold in constructing a skin substitute containing ESCs for the repair of full-thickness skin defects.

A new strategy of promoting vascularization of skin substitutes by capturing endothelial progenitor cells automatically.

How to promote vascularization of a skin substitute is the key to successful skin transplantation. Current methods are mainly through releasing angiogenesis-related factors (ARF) or seeding angiogenesis-related cells (ARC), but the efficacy of these methods is not satisfactory, because angiogenesis needs participation of multiple factors, extracellular matrix and related cells. The latest research has demonstrated that endothelial progenitor cells (EPCs) originating from bone marrow and existing in peripheral blood are the key element participating in revascularization of adult tissues. They directly participate in both stem cell vasculogenesis of ischemic tissues and local angiogenesis. We therefore hypothesize whether it is possible to construct a new skin substitute and use it to mobilize EPCs in bone marrow to peripheral circulation and capture EPCs automatically as a simple and effective method of promoting vascularization of the skin substitute for the sake of improving its post-transplant survival.

Biphasic effects of selective inhibition of transforming growth factor beta1 activin receptor-like kinase on LPS-induced lung injury.

The present study was designed to find out whether SB431542, an inhibitor of transforming growth factor beta1 activin receptor-like kinase, could protect the lung from LPS-induced injury. Inflammatory lung injury model was induced by intratracheal administration of LPS. C57BL/6 mice were randomly divided into the sham control group (S group), the LPS stimulation group (L group), the LPS + early SB431542 treatment group (Ie group), and the LPS + delayed SB431542 treatment group (Id group). SB431542 was admitted intraperitoneally on study days 1, 2, and 3 to the mice in Ie group, whereas those in Id group received the same dose of SB431542 on study days 4, 5, and 6. Pulmonary TNF-alpha and IL- 1beta mRNA expressions were tested. Pathological evaluations of pulmonary alveolitis and collagen deposition and fibrosis were performed on study days 7 and 28, along with the determination of pulmonary hydroxyproline, matrix metalloproteinase 9, and tissue inhibitor of matrix metalloproteinase 1 on study day 28. As a result, LPS stimulation resulted in significant increases of the pulmonary TNF-alpha and IL-1beta mRNA expressions as well as pathological scores for alveolitis on day 7 and increased collagen deposition, hydroxyproline content, and pathological scores for fibrosis on day 28, with a decrease of matrix metalloproteinase 9 activity. Those parameters were further aggravated in the Ie group whereas relieved significantly in the Id group. These data suggest that SB431542 therapy for inflammatory lung injury could be harmful if performed during early-phase inflammatory response. However, the therapy would prevent lung from inflammatory injury and fibrosis if it was initiated late.

[Repair of deep burn and traumatic wounds in lower extremities with combined transplantation of multiple pedicled skin flaps].

OBJECTIVE: To summarize the clinical experience in repair of deep burn and traumatic wounds with combined transplantation of different types of pedicled skin flaps in lower extremities. METHODS: Two hundred and thirty-six patients with 271 deep wounds in lower extremities after burn or trauma were repaired with muscular skin flaps, local fascial flaps and island flaps with vascular pedicle (more than 20 types) in our department from Jan. 1998 to Sept. 2008. RESULTS: Complete necrosis of skin flaps occurred in 1 case, congestion and necrosis over the edge of skin flaps occurred in 3 cases, which were healed after grafting, and other skin flaps survived well with soft texture. Skin flaps were too bulky in 26 cases, among them 17 cases were thinned, and the appearance of other skin flaps were satisfactory. In 68 patients with functional region injury were recovered to certain extent without contracture. CONCLUSIONS: Skin flaps with pedicles, multiple transplantations if necessary, can repair deep wounds satisfactorily in lower extremities after deep burn or trauma injury.

[Reconstruction and transplantation of the composite skin comprising epithelial growth factor gene-transfected keratinocytes].

OBJECTIVE: To investigate the epithelial growth factor (EGF) expression of EGF gene-transfected keratinocytes and its effect on cell proliferation after grafting. METHODS: Newborn Balb/c mouse keratinocytes and gene transfected keratinocytes were seeded on the surface of acellular dermal matrix and cocultured in different ratios as follows: 1:1, 1:3, or 1:5 1 week after culture. The composite skin was grafted onto the full-thickness wound in Balb/c mouse. Specimen was harvested at interval after grafting and underwent the immunohistochemistry staining for EGF and proliferating cell nuclear antigen (PCNA). RESULTS: Immunohistochemical staining showed EGF was expressed in the newly generated epidermis 1-2 week after grafting of the composite skin comprising Balb/c mouse keratinocytes and gene-transfected keratinocytes (at the ratio of 1:5). One week after surgery, Anti-PCNA positive basal cells were more than that in composite skin containing Balb/c mouse keratinocytes alone (P<0.01). CONCLUSION: The gene-transfected keratinocytes expresses EGF and promotes the proliferation of keratinocytes in the early stage after transplantation.

[Clinical observation of the long-term effects of rhEGF on deep partial-thickness burn wounds].

OBJECTIVE: To evaluate the safety and long-term effect of recombinant human epithelial growth factor (rhEGF) on deep partial-thickness burn wounds. METHODS: Thirty-seven burn patients were enrolled in this study and were observed by randomized, double-blinded and placebo-controlled protocol. An area of deep partial-thickness burn wounds from each patient was divided into control (C) and treatment (T) portions. The wound in C was treated with normal saline while that in T with rhEGF. The patients were followed-up for 1 and 4 years after wound healing. The healed wounds were evaluated by modified Vancouver scar scale in terms of scar index (SI). RESULTS: 1 year after wound healing, it was found that the SI in T group (7.19 +/- 1.67) was obviously lower than that in C group (8.92 +/- 1.78, P < 0.01). The SI in T group (6.12 +/- 1.54) was still evidently lower than that in C group (8.09 +/- 1.81, P < 0.01) four years after wound healing. There were no signs of development of tumor or cancer in all the tested burn wound areas. CONCLUSION: External application of rhEGF might be beneficial to the healing quality of deep partial-thickness burn wound with less scar formation and better long-term effects, and it is safe.

[Inhibition of nimodipine on production of proinflammatory by Kupffer cells in severe burned rats].

OBJECTIVE: To study whether nimodipine, a dihydropyridine-type calcium channel blocker, can inhibit the production of interleukin-1beta(IL-1beta), interleukin-6(IL-6) by Kupffer cells(KC) and down-regulate its level of plasma after severe burn injury. METHODS: KC of normal rats were isolated with portal vein catheter, intrahepatic digestion and density gradient centrifugation. Intracellular calcium concentration ([Ca2+]i) in individual KC after stimulated with postburn serum was assessed fluorometrically with microspectrofluorimeter. Level of IL-1beta and IL-6 in the supernatant of KC cultured with postburn serum were detected by enzyme-linked immunosorbent assay(ELISA). SD rats underwent 30% total body surface area(TBSA) full thickness burn 6 hours later, KCs was isolated and their mRNA were extracted. Level of IL-1beta mRNA and IL-6 mRNA were detected by ribonuclease protection assay(RPA). Levels of plasma IL-1beta and IL-6 were also detected. Role of nimodipine on above-mentioned effects were observed. RESULTS: Compared with that of control group, levels of [Ca2+]i of KCs and IL-1beta and IL-6 supernatant in burn group increased significantly(all P<0.01). At present of 1 micromol/L nimodipine, however, the [Ca2+]i, IL-1beta, IL-6 values decreased significantly(all P<0.01). The level of plasma cytokines and KC mRNA in burn group also increased significantly. After intravenously injection with nimodipine (40 microg x kg(-1) x h(-1)), the numerical values decreased significantly(all P<0.01). CONCLUSION: Kupffer cells of rats are activated to secret IL-1beta and IL-6 after severe burn injury and this process is realized through calcium ion signal transduction channel. Nimodipine can inhibit IL-1beta and IL-6 production of KC by preventing its mRNA transcription, down-regulating its level of plasma.

[The role of Kupffer cells on the postburn production of TNFalpha, IL-1beta and IL-6 in severely scalded rats].

OBJECTIVE: To observe the role of Kupffer cells in the postburn production of TNFalpha, IL-1beta and IL-6 in severely scalded rats. METHODS: (1) The production of TNFalpha, IL-1beta and IL-6 from rat Kupffer cells stimulated by burn serum was observed. (2) The postburn change in the expression of cytokine mRNA from rat Kupffer cells was monitored. (3) The change in the plasma cytokine contents in scalded rats was determined after the application of gadolinium chloride, a specific inhibitor of Kupffer cells. RESULTS: Kupffer cells could be stimulated by burn serum to release cytokines TNFalpha, IL-1beta and IL-6. The mRNA expression of TNFalpha, IL-1beta and IL-6 from rat Kupffer cells increased significantly after injury. But the postburn plasma levels of TNFalpha, IL-1beta and IL-6 decreased obviously to 34.71%, 36.99% and 33.7% of those in scalding group, respectively, after the Kupffer cell activity was inhibited. CONCLUSION: The plasma cytokines, i.e. TNFalpha, IL-1beta and IL-6, were primarily produced from Kupffer cells after injury in scalded rats, initiated by TNFalpha, IL-1beta and IL-6 mRNA transcription.