Aim To study the theory and method for the prediction of service life of solid rocket propellant grain. Methods With the aid of discontiguous diagnostic technology and method of accumulated damage using accelerated...Aim To study the theory and method for the prediction of service life of solid rocket propellant grain. Methods With the aid of discontiguous diagnostic technology and method of accumulated damage using accelerated aging or heat air oven, the aging isotherms for void content versus aging time were determined. According to the principle of time temperature equivalence the viscoelastic master curve for the prediction of service life were obtained. Results and Conclusion The service life of HMX CMDB solid rocket propellant grain were obtained. Because the critical storage life is measured, the accuracy of predicting the service life of the grain has been increased greatly.展开更多
In this case study,we analyzed the wound-healing process of a patient with a chronic wound who underwent fire needle treatment,and we tracked the coverage of granulation tissue and decrease of slough and exudate.An 85...In this case study,we analyzed the wound-healing process of a patient with a chronic wound who underwent fire needle treatment,and we tracked the coverage of granulation tissue and decrease of slough and exudate.An 85-year-old man had repeated right shoulder and back pain,itching,and skin festering for more than 1.5 years.A fire needle was administered combined with moist dressing once every 5 days to promote wound healing.After six rounds of fire needle treatment,granulation tissue formed over the surface of the wound base,the depth of the wound had become shallow,and the wound area was reduced.No complications occurred during the intervention.Fire needle therapy combined with a moist wound-healing dressing can be an effective alternative approach in managing chronic wounds.展开更多
To investigate the inhibiting effect of β-Aescin on nuclear factor-κB (NF-κB) activation and the expression of tumor necrosis factor-α (TNF-α) protein after traumatic brain injury (TBI) in the rat brain, 62 SD ra...To investigate the inhibiting effect of β-Aescin on nuclear factor-κB (NF-κB) activation and the expression of tumor necrosis factor-α (TNF-α) protein after traumatic brain injury (TBI) in the rat brain, 62 SD rats were subjected to lateral cortical impact injury caused by a free-falling object and divided randomly into four groups: (1) sham operated (Group A); (2) injured (Group B); (3) β-Aescin treatment (Group C); (4) pyrrolidine dithocarbamate (PDTC) treatment (Group D). β-Aescin was administered in Group C and PDTC treated in Group D immediately after injury. A series of brain samples were obtained directly 6h, 24 h and 3 d respectively after trauma in four groups. NF-κB activation was examined by Electrophoretic Mobility Shift Assay (EMSA); the levels of TNF-α protein were measured by radio-immunoassay (RIA); the water content of rat brain was measured and pathomorphological observation was carried out. NF-κB activation, the levels of TNF-α protein and the water content of rat brain were significantly increased (P<0.01) following TBI in rats. Compared with Group B, NF-κB activation (P<0.01), the levels of TNF-α protein (P<0.01) and the water content of brain (P<0.05) began to decrease obviously after injury in Groups C and D.β-Aescin could dramatically inhibit NF-κB activation and the expression of TNF-α protein in the rat brain, alleviate rat brain edema, and that could partially be the molecular mechanism by which β-Aescin attenuates traumatic brain edema.展开更多
Objective: To investigate the role of spinal glial cells activation in neuropathic pain in a recently developed spared nerve injury (SNI) animal model by Decosterd and Woolf. Methods: A lesion was made to two of the t...Objective: To investigate the role of spinal glial cells activation in neuropathic pain in a recently developed spared nerve injury (SNI) animal model by Decosterd and Woolf. Methods: A lesion was made to two of the three terminal branches of the sciatic nerve of rats (tibial and common peroneal nerves) leaving the sural nerve intact. Continuous intrathe-cal administration of propentofylline, a glial modulating agent, 1 d before and 5 d after operation, was performed to disrupt spinal cord glia function. The vehicle was intrathecally administrated as control. The paw withdrawal threshold to mechanical stimulation (paw withdrawal mechaical threshold PWMT), body mass and motor function were determined pre- and post-surgery. Results: It produced a prolonged mechanical allodynia in the medial and lateral part of the ipsilateral hind paw in SNL models. The treatment with propentofylline significantly prevented the development of mechanical allodynia located in either medial or lateral plantar surface. Rats in two groups showed normal motor function and body weight increase. Conclusion: SNI model can be applied as a useful method with little variance in searching the mechanism of neuropathic pain. These study suggest that spinal glia activation may contribute to mechanical allodynia induced by SNI.展开更多
Objective Ultraviolet B(UVB)mainly acts on the skin epidermis,causing oxidative damage and apoptosis of keratinocytes.Jin Bai Mei Yan Prescription(JBMYP)comprises a variety of antioxidant traditional Chinese medicines...Objective Ultraviolet B(UVB)mainly acts on the skin epidermis,causing oxidative damage and apoptosis of keratinocytes.Jin Bai Mei Yan Prescription(JBMYP)comprises a variety of antioxidant traditional Chinese medicines(TCM).In this study,we aimed to evaluate the effects of JBMYP on the oxidative damage induced by UVB in human immortalized epidermal keratinocytes(HaCaT)cells.Methods HaCaT cells were divided into six groups:control group,model(UVB)group,positive(UVB+vitamin E)group,UVB+JBMYP low dose group(160μg/mL),UVB+JBMYP moderate dose group(800μg/mL),and UVB+JBMYP high dose group(1600μg/mL).HaCaT cells were irradiated with UVB and treated with JBMYP for 24 h.Methyl thiazolyl tetrazolium(MTT)assay and real-time unlabeled cell function analyzer were used to assess the cell survival and proliferation rates,respectively.At the same time,the levels of intracellular reactive oxygen species(ROS),lipid peroxide malondialdehyde(MDA),glutathione(GSH),and hydroxyproline(HYP),as well as the activities of antioxidant enzyme superoxide dismutase(SOD)and catalase(CAT)were evaluated using enzyme linked immunosorbent assay(ELISA).Results Compared with the model group,the survival rate of HaCaT cells in each dosage group of JBMYP was significantly improved(P<0.05).Further,JBMYP could promote the proliferation of HaCaT cells,leading to a reduction in the contents of MDA and ROS,and increase in the contents of SOD,CAT,GSH and HYP in HaCaT cells.Conclusions JBMYP has enhanced protective effect on oxidative damage induced by UVB in HaCaT cells.展开更多
Objectives: The burn repair associated with diabetes complications showed considerable changes in the healing process and the development of alternative therapies to favor the repair is important. This study investig...Objectives: The burn repair associated with diabetes complications showed considerable changes in the healing process and the development of alternative therapies to favor the repair is important. This study investigated the efficacy of the Casearia sylvestris in the burn repair in diabetic and non-diabetic rats. Methods: The animals were divided into four groups (n = 20): (C) non-diabetics treated with carbopol gel; (G) non-diabetic treated with C. sylvestris extract in carbopol gel; (DM-C) diabetics treated with carbopol gel; (DM-G) diabetics treated with C. sylvestris extract in carbopol gel. Burn was induced using a metal plate (2 cm diameter/120 °C/20 sec). Samples were collected on the 3rd, 7th, 14th and 21st days after the injury for histomorphometric analysis (inflammatory infiltrate, fibroblasts, blood vessels and collagen), MPO (Myeloperoxidase) and NAG (N-Acetilglicosaminidase) dosage, hydroxyproline, glycosaminoglycans, TGF-β1, VEGF, collagen I and III. Key findings: C. sylvestris decreased the inflammatory process during the experimental period in diabetic and non-diabetic animals which has been demonstrated by MPO, NAG quantification, and TGF-β1 expression. C. sylvestris also increased blood vessels and decreased VEGF expression during the studied period in non-diabetic animals. Fibroplasia and collagenase were increased in all experimental periods in the DM-G group by means of de hydroxyproline quantification, collagen I, collagen III and glycosaminoglycans. Conclusions: C. sylvestris application can modulate favorably the time of inflammation and collagenous process in the repair of burn injuries in diabetic rats.展开更多
Tissue homeostasis requires a carefully-orchestrated balance between cell proliferation, cellular senescence and cell death. Cells proliferate through a cell cycle that is tightly regulated by cyclin-dependent kinase ...Tissue homeostasis requires a carefully-orchestrated balance between cell proliferation, cellular senescence and cell death. Cells proliferate through a cell cycle that is tightly regulated by cyclin-dependent kinase activities. Cellular senescence is a safeguard program limiting the proliferative competence of cells in living organisms. Apoptosis eliminates unwanted cells by the coordinated activity of gene products that regulate and effect cell death. The intimate link between the cell cycle, cellular senes- cence, apoptosis regulation, cancer development and tumor responses to cancer treatment has become eminently apparent. Extensive research on tumor suppressor genes, oncogenes, the cell cycle and apoptosis regulatory genes has revealed how the DNA damage-sensing and -signaling pathways, referred to as the DNA-damage response network, are tied to cell proliferation, cell-cycle arrest, cellular senescence and apoptosis. DNA-damage responses are complex, involving “sensor” proteins that sense the damage, and transmit signals to “transducer” proteins, which, in turn, convey the signals to numerous “effector” proteins implicated in specific cellular pathways, including DNA repair mechanisms, cell-cycle checkpoints, cellular senescence and apoptosis. The Bcl-2 family of proteins stands among the most crucial regulators of apoptosis and performs vital functions in deciding whether a cell will live or die after cancer chemotherapy and irradiation. In addition, several studies have now revealed that members of the Bcl-2 family also interface with the cell cycle, DNA repair/recombination and cellular senescence, effects that are generally distinct from their function in apoptosis. In this review, we report progress in understanding the molecular networks that regulate cell-cycle checkpoints, cellular senescence and apoptosis after DNA damage, and discuss the influence of some Bcl-2 family members on cell-cycle checkpoint regulation.展开更多
In this short review we describe implications of age-related changes of protein and DNA oxidation as a public mechanism of biological aging. Oxidatively modified protein and DNA have been demonstrated to increase with...In this short review we describe implications of age-related changes of protein and DNA oxidation as a public mechanism of biological aging. Oxidatively modified protein and DNA have been demonstrated to increase with advancing age in rodents. Half-life of proteins is extended and DNA repair activity declines in old animals. Dietary restriction initiated late in life can shorten the half-life of proteins to levels of young animals, thus contributing to reduce level of altered proteins in old animals by the regimen. Regular exercise reduced oxidatively modified proteins in the brain with improved cognitive functions. It attenuated oxidative stress in the liver, i.e., ameliorating activation of nuclear factor κB, increasing reduced glutathione, and decreasing oxidized guanine base in nuclear and mitochondrial DNA. These findings suggest that regular exercise has systemic effects in reducing oxidative stress. Thus, life-styles such as diet and exercise may extend health span, by up-regulating overall anti-oxidant capacities that include proteins involved in protein turnover and DNA repair, resulting in reduction of damaged proteins and DNA that potentially promote physiological and pathological aging.展开更多
AIM: To determine if blockade of P-selectin in the isolated blood-perfused cold ex vivo rat liver model protects the liver from ischemia-reperfusion injury. METHODS: The effect of P-selectin blockade was assessed by...AIM: To determine if blockade of P-selectin in the isolated blood-perfused cold ex vivo rat liver model protects the liver from ischemia-reperfusion injury. METHODS: The effect of P-selectin blockade was assessed by employing an isolated blood-perfused cold ex vivo rat liver with or without P-selectin antibody treatment before and after 6 h of cold storage in University of Wisconsin solution. RESULTS: In our isolated blood-perfused rat liver model, pre-treatment with P-selectin antibody failed to protect the liver from ischemia-reperfusion injury, as judged by the elevated aspartate aminotransferase activity. In addition, P-selectin antibody treatment did not significantly reduced hepatic polymorphonuclear leukocyte accumulation after 120 min of perfusion. Histological evaluation of liver sections obtained at 120 min of perfusion showed significant oncotic necrosis in liver sections of both ischemic control and P-selectin antibody-treated groups. However, total bile production after 120 rain of perfusion was significantly greater in P-selectin antibody-treated livers, compared to control livers. No significant difference in P-selectin and ICAM-1 mRNAs and proteins, GSH, GSSG, and nuclear NF-kB was found between control and P-selectin antibody-treated livers. CONCLUSION: In conclusion, we have shown that blockade of P-selectin alone failed to reduced polymorphonuclear leukocyte accumulation in the liver and protect hepatocytes from ischemia-reperfusion injury in the isolated blood-perfused cold-ex vivo rat liver model.展开更多
In the present study, the involvement of L-arginine(L-Arg) NO on the protective action of electroacupuncture(EA) on cerebral ischemic injury was observed in acute ischemia-reperfusion(IR) rat model by taking regional ...In the present study, the involvement of L-arginine(L-Arg) NO on the protective action of electroacupuncture(EA) on cerebral ischemic injury was observed in acute ischemia-reperfusion(IR) rat model by taking regional cerebral blood flow(r-CBF),cerebral water content(CWC),and blood nitric oxide(NO) contents as indexes. Results showed that 1) EA could cause r-CBF and serum NO content to increase and CWC to lower, suggesting an protective action of EA on IR cerebral injury; 2) intravenous injection of L-Arg also had an protective effect on cerebral IR cerebral injury, while L-NNA had no this effect; and 3) pre-treatment with L-Arg might strengthen the effect of EA further, while pretreatment with L-NNA could weaken its effect. It indicates that L-Arg-NO may be involved in the effect of EA in protecting the brain from ischemic injury.展开更多
The objective of the present study was to determine the effect of different sources of dietary fibre on the oxidative stress induced by a high fat diet in laboratory rats. Thirty two laboratory rats were penned indivi...The objective of the present study was to determine the effect of different sources of dietary fibre on the oxidative stress induced by a high fat diet in laboratory rats. Thirty two laboratory rats were penned individually and divided into four groups: CONT (high fat diet), G (70 g guar gum/kg), P (70 g apple pectin/kg) and WB (155 g wheat bran/kg). After 11 or 13 days of treatment DNA damage of blood leukocytes was measured by Comet assay and lipid peroxidation was studied by determining the malondialdehyde (MDA) concentration in liver and in urine. In comparison with group CONT, the degree of DNA damage was significantly lower in group WB. In groups G and P DNA damage was also reduced but not significantly. Similar results were also obtained for the liver MDA concentration. All three studied groups showed reduced liver MDA concentrations but only group WB was significant compared to group CONT. In comparison with group CONT, the groups WB and P had significantly reduced 24-hour urine MDA excretion, hut not group G. The results of the experiment confirmed that wheat bran intake effectively reduces oxidative stress induced by a high fat diet.展开更多
Objective: Whether early massive bronchoalveolar lavage can remove the harmful substances from the lungs injured with smoke inhalation remains uncertain. This study was designed to observe the effects of early massive...Objective: Whether early massive bronchoalveolar lavage can remove the harmful substances from the lungs injured with smoke inhalation remains uncertain. This study was designed to observe the effects of early massive bronchoalveolar lavage fluid (BALF) on the healthy lungs in rats. Methods: Mongrel dogs were inflicted with severe smoke inhalation injury. The injured lungs were lavaged with large amount of normal saline in the first hour after injury and the BALF was collected. The BALF was injected into the healthy lungs of 30 rats (group C) in the dosage of 5 ml/kg. The functions and pathological changes of the lungs were observed 24 h after perfusion with the BALF. The data were compared with those of 23 rats (group B) whose lungs were perfused with the BALF collected from normal dogs and those of 21 rats (group A) whose lungs were perfused with normal saline. Results: The mortality rate 24 h after lung perfusion was higher in group C than in groups A and B. The survivors of group C exhibited fluctuation of respiratory rate (RR), remarkable decrease of PaO 2, significantly higher content of lung water, decrease of total static pulmonary compliance and pulmonary expansion index, and increasse of inflammatory cytokines in the tissues of lungs. Only slight mechanic obstructive effect on the airway was observed in rats of group A and B. The pathological changes of the lungs of the rats in group C were similar to those of the dogs with actual smoke inhalation injury. Conclusion: Our findings indicate that the BALF collected from dogs with acute severe smoke inhalation injury in the early stage after injury injured the normal lungs of rats with the bioactive substances in the BALF. These findings show us that it is a valuable therapeutic procedure to apply massive bronchoalveolar fluid lavage in the early stage after inhalation injury.展开更多
文摘Aim To study the theory and method for the prediction of service life of solid rocket propellant grain. Methods With the aid of discontiguous diagnostic technology and method of accumulated damage using accelerated aging or heat air oven, the aging isotherms for void content versus aging time were determined. According to the principle of time temperature equivalence the viscoelastic master curve for the prediction of service life were obtained. Results and Conclusion The service life of HMX CMDB solid rocket propellant grain were obtained. Because the critical storage life is measured, the accuracy of predicting the service life of the grain has been increased greatly.
基金This research was funded by grants from The First Affiliated Hospital Project of Guangzhou University of Chinese Medicine(No.2017HL01)
文摘In this case study,we analyzed the wound-healing process of a patient with a chronic wound who underwent fire needle treatment,and we tracked the coverage of granulation tissue and decrease of slough and exudate.An 85-year-old man had repeated right shoulder and back pain,itching,and skin festering for more than 1.5 years.A fire needle was administered combined with moist dressing once every 5 days to promote wound healing.After six rounds of fire needle treatment,granulation tissue formed over the surface of the wound base,the depth of the wound had become shallow,and the wound area was reduced.No complications occurred during the intervention.Fire needle therapy combined with a moist wound-healing dressing can be an effective alternative approach in managing chronic wounds.
文摘To investigate the inhibiting effect of β-Aescin on nuclear factor-κB (NF-κB) activation and the expression of tumor necrosis factor-α (TNF-α) protein after traumatic brain injury (TBI) in the rat brain, 62 SD rats were subjected to lateral cortical impact injury caused by a free-falling object and divided randomly into four groups: (1) sham operated (Group A); (2) injured (Group B); (3) β-Aescin treatment (Group C); (4) pyrrolidine dithocarbamate (PDTC) treatment (Group D). β-Aescin was administered in Group C and PDTC treated in Group D immediately after injury. A series of brain samples were obtained directly 6h, 24 h and 3 d respectively after trauma in four groups. NF-κB activation was examined by Electrophoretic Mobility Shift Assay (EMSA); the levels of TNF-α protein were measured by radio-immunoassay (RIA); the water content of rat brain was measured and pathomorphological observation was carried out. NF-κB activation, the levels of TNF-α protein and the water content of rat brain were significantly increased (P<0.01) following TBI in rats. Compared with Group B, NF-κB activation (P<0.01), the levels of TNF-α protein (P<0.01) and the water content of brain (P<0.05) began to decrease obviously after injury in Groups C and D.β-Aescin could dramatically inhibit NF-κB activation and the expression of TNF-α protein in the rat brain, alleviate rat brain edema, and that could partially be the molecular mechanism by which β-Aescin attenuates traumatic brain edema.
文摘Objective: To investigate the role of spinal glial cells activation in neuropathic pain in a recently developed spared nerve injury (SNI) animal model by Decosterd and Woolf. Methods: A lesion was made to two of the three terminal branches of the sciatic nerve of rats (tibial and common peroneal nerves) leaving the sural nerve intact. Continuous intrathe-cal administration of propentofylline, a glial modulating agent, 1 d before and 5 d after operation, was performed to disrupt spinal cord glia function. The vehicle was intrathecally administrated as control. The paw withdrawal threshold to mechanical stimulation (paw withdrawal mechaical threshold PWMT), body mass and motor function were determined pre- and post-surgery. Results: It produced a prolonged mechanical allodynia in the medial and lateral part of the ipsilateral hind paw in SNL models. The treatment with propentofylline significantly prevented the development of mechanical allodynia located in either medial or lateral plantar surface. Rats in two groups showed normal motor function and body weight increase. Conclusion: SNI model can be applied as a useful method with little variance in searching the mechanism of neuropathic pain. These study suggest that spinal glia activation may contribute to mechanical allodynia induced by SNI.
基金funding support from the National Administration of Traditional Chinese Medicine(No.2017-149-11)National Base for International Cooperation(No.2016-65)Henan Province Industry-University-Research Collaboration(No.182107000029)to conduct the Special Project on Standardization of Traditional Chinese Medicine。
文摘Objective Ultraviolet B(UVB)mainly acts on the skin epidermis,causing oxidative damage and apoptosis of keratinocytes.Jin Bai Mei Yan Prescription(JBMYP)comprises a variety of antioxidant traditional Chinese medicines(TCM).In this study,we aimed to evaluate the effects of JBMYP on the oxidative damage induced by UVB in human immortalized epidermal keratinocytes(HaCaT)cells.Methods HaCaT cells were divided into six groups:control group,model(UVB)group,positive(UVB+vitamin E)group,UVB+JBMYP low dose group(160μg/mL),UVB+JBMYP moderate dose group(800μg/mL),and UVB+JBMYP high dose group(1600μg/mL).HaCaT cells were irradiated with UVB and treated with JBMYP for 24 h.Methyl thiazolyl tetrazolium(MTT)assay and real-time unlabeled cell function analyzer were used to assess the cell survival and proliferation rates,respectively.At the same time,the levels of intracellular reactive oxygen species(ROS),lipid peroxide malondialdehyde(MDA),glutathione(GSH),and hydroxyproline(HYP),as well as the activities of antioxidant enzyme superoxide dismutase(SOD)and catalase(CAT)were evaluated using enzyme linked immunosorbent assay(ELISA).Results Compared with the model group,the survival rate of HaCaT cells in each dosage group of JBMYP was significantly improved(P<0.05).Further,JBMYP could promote the proliferation of HaCaT cells,leading to a reduction in the contents of MDA and ROS,and increase in the contents of SOD,CAT,GSH and HYP in HaCaT cells.Conclusions JBMYP has enhanced protective effect on oxidative damage induced by UVB in HaCaT cells.
文摘Objectives: The burn repair associated with diabetes complications showed considerable changes in the healing process and the development of alternative therapies to favor the repair is important. This study investigated the efficacy of the Casearia sylvestris in the burn repair in diabetic and non-diabetic rats. Methods: The animals were divided into four groups (n = 20): (C) non-diabetics treated with carbopol gel; (G) non-diabetic treated with C. sylvestris extract in carbopol gel; (DM-C) diabetics treated with carbopol gel; (DM-G) diabetics treated with C. sylvestris extract in carbopol gel. Burn was induced using a metal plate (2 cm diameter/120 °C/20 sec). Samples were collected on the 3rd, 7th, 14th and 21st days after the injury for histomorphometric analysis (inflammatory infiltrate, fibroblasts, blood vessels and collagen), MPO (Myeloperoxidase) and NAG (N-Acetilglicosaminidase) dosage, hydroxyproline, glycosaminoglycans, TGF-β1, VEGF, collagen I and III. Key findings: C. sylvestris decreased the inflammatory process during the experimental period in diabetic and non-diabetic animals which has been demonstrated by MPO, NAG quantification, and TGF-β1 expression. C. sylvestris also increased blood vessels and decreased VEGF expression during the studied period in non-diabetic animals. Fibroplasia and collagenase were increased in all experimental periods in the DM-G group by means of de hydroxyproline quantification, collagen I, collagen III and glycosaminoglycans. Conclusions: C. sylvestris application can modulate favorably the time of inflammation and collagenous process in the repair of burn injuries in diabetic rats.
基金the Canadian Institutes of Health Research and the Cancer Research Society, and fellowships by the Health Research Funds of Quebec, Canada
文摘Tissue homeostasis requires a carefully-orchestrated balance between cell proliferation, cellular senescence and cell death. Cells proliferate through a cell cycle that is tightly regulated by cyclin-dependent kinase activities. Cellular senescence is a safeguard program limiting the proliferative competence of cells in living organisms. Apoptosis eliminates unwanted cells by the coordinated activity of gene products that regulate and effect cell death. The intimate link between the cell cycle, cellular senes- cence, apoptosis regulation, cancer development and tumor responses to cancer treatment has become eminently apparent. Extensive research on tumor suppressor genes, oncogenes, the cell cycle and apoptosis regulatory genes has revealed how the DNA damage-sensing and -signaling pathways, referred to as the DNA-damage response network, are tied to cell proliferation, cell-cycle arrest, cellular senescence and apoptosis. DNA-damage responses are complex, involving “sensor” proteins that sense the damage, and transmit signals to “transducer” proteins, which, in turn, convey the signals to numerous “effector” proteins implicated in specific cellular pathways, including DNA repair mechanisms, cell-cycle checkpoints, cellular senescence and apoptosis. The Bcl-2 family of proteins stands among the most crucial regulators of apoptosis and performs vital functions in deciding whether a cell will live or die after cancer chemotherapy and irradiation. In addition, several studies have now revealed that members of the Bcl-2 family also interface with the cell cycle, DNA repair/recombination and cellular senescence, effects that are generally distinct from their function in apoptosis. In this review, we report progress in understanding the molecular networks that regulate cell-cycle checkpoints, cellular senescence and apoptosis after DNA damage, and discuss the influence of some Bcl-2 family members on cell-cycle checkpoint regulation.
文摘In this short review we describe implications of age-related changes of protein and DNA oxidation as a public mechanism of biological aging. Oxidatively modified protein and DNA have been demonstrated to increase with advancing age in rodents. Half-life of proteins is extended and DNA repair activity declines in old animals. Dietary restriction initiated late in life can shorten the half-life of proteins to levels of young animals, thus contributing to reduce level of altered proteins in old animals by the regimen. Regular exercise reduced oxidatively modified proteins in the brain with improved cognitive functions. It attenuated oxidative stress in the liver, i.e., ameliorating activation of nuclear factor κB, increasing reduced glutathione, and decreasing oxidized guanine base in nuclear and mitochondrial DNA. These findings suggest that regular exercise has systemic effects in reducing oxidative stress. Thus, life-styles such as diet and exercise may extend health span, by up-regulating overall anti-oxidant capacities that include proteins involved in protein turnover and DNA repair, resulting in reduction of damaged proteins and DNA that potentially promote physiological and pathological aging.
基金Supported by Grants from the American Liver Foundation, Naomi Judd Liver Scholar Award, The American Surgical Association Career Development Fellowship, and National Ⅰ
文摘AIM: To determine if blockade of P-selectin in the isolated blood-perfused cold ex vivo rat liver model protects the liver from ischemia-reperfusion injury. METHODS: The effect of P-selectin blockade was assessed by employing an isolated blood-perfused cold ex vivo rat liver with or without P-selectin antibody treatment before and after 6 h of cold storage in University of Wisconsin solution. RESULTS: In our isolated blood-perfused rat liver model, pre-treatment with P-selectin antibody failed to protect the liver from ischemia-reperfusion injury, as judged by the elevated aspartate aminotransferase activity. In addition, P-selectin antibody treatment did not significantly reduced hepatic polymorphonuclear leukocyte accumulation after 120 min of perfusion. Histological evaluation of liver sections obtained at 120 min of perfusion showed significant oncotic necrosis in liver sections of both ischemic control and P-selectin antibody-treated groups. However, total bile production after 120 rain of perfusion was significantly greater in P-selectin antibody-treated livers, compared to control livers. No significant difference in P-selectin and ICAM-1 mRNAs and proteins, GSH, GSSG, and nuclear NF-kB was found between control and P-selectin antibody-treated livers. CONCLUSION: In conclusion, we have shown that blockade of P-selectin alone failed to reduced polymorphonuclear leukocyte accumulation in the liver and protect hepatocytes from ischemia-reperfusion injury in the isolated blood-perfused cold-ex vivo rat liver model.
文摘In the present study, the involvement of L-arginine(L-Arg) NO on the protective action of electroacupuncture(EA) on cerebral ischemic injury was observed in acute ischemia-reperfusion(IR) rat model by taking regional cerebral blood flow(r-CBF),cerebral water content(CWC),and blood nitric oxide(NO) contents as indexes. Results showed that 1) EA could cause r-CBF and serum NO content to increase and CWC to lower, suggesting an protective action of EA on IR cerebral injury; 2) intravenous injection of L-Arg also had an protective effect on cerebral IR cerebral injury, while L-NNA had no this effect; and 3) pre-treatment with L-Arg might strengthen the effect of EA further, while pretreatment with L-NNA could weaken its effect. It indicates that L-Arg-NO may be involved in the effect of EA in protecting the brain from ischemic injury.
文摘The objective of the present study was to determine the effect of different sources of dietary fibre on the oxidative stress induced by a high fat diet in laboratory rats. Thirty two laboratory rats were penned individually and divided into four groups: CONT (high fat diet), G (70 g guar gum/kg), P (70 g apple pectin/kg) and WB (155 g wheat bran/kg). After 11 or 13 days of treatment DNA damage of blood leukocytes was measured by Comet assay and lipid peroxidation was studied by determining the malondialdehyde (MDA) concentration in liver and in urine. In comparison with group CONT, the degree of DNA damage was significantly lower in group WB. In groups G and P DNA damage was also reduced but not significantly. Similar results were also obtained for the liver MDA concentration. All three studied groups showed reduced liver MDA concentrations but only group WB was significant compared to group CONT. In comparison with group CONT, the groups WB and P had significantly reduced 24-hour urine MDA excretion, hut not group G. The results of the experiment confirmed that wheat bran intake effectively reduces oxidative stress induced by a high fat diet.
基金SupportedbytheFoundationforthe"NinthFive yearPlan"ofPLA (No .96L0 4 3)
文摘Objective: Whether early massive bronchoalveolar lavage can remove the harmful substances from the lungs injured with smoke inhalation remains uncertain. This study was designed to observe the effects of early massive bronchoalveolar lavage fluid (BALF) on the healthy lungs in rats. Methods: Mongrel dogs were inflicted with severe smoke inhalation injury. The injured lungs were lavaged with large amount of normal saline in the first hour after injury and the BALF was collected. The BALF was injected into the healthy lungs of 30 rats (group C) in the dosage of 5 ml/kg. The functions and pathological changes of the lungs were observed 24 h after perfusion with the BALF. The data were compared with those of 23 rats (group B) whose lungs were perfused with the BALF collected from normal dogs and those of 21 rats (group A) whose lungs were perfused with normal saline. Results: The mortality rate 24 h after lung perfusion was higher in group C than in groups A and B. The survivors of group C exhibited fluctuation of respiratory rate (RR), remarkable decrease of PaO 2, significantly higher content of lung water, decrease of total static pulmonary compliance and pulmonary expansion index, and increasse of inflammatory cytokines in the tissues of lungs. Only slight mechanic obstructive effect on the airway was observed in rats of group A and B. The pathological changes of the lungs of the rats in group C were similar to those of the dogs with actual smoke inhalation injury. Conclusion: Our findings indicate that the BALF collected from dogs with acute severe smoke inhalation injury in the early stage after injury injured the normal lungs of rats with the bioactive substances in the BALF. These findings show us that it is a valuable therapeutic procedure to apply massive bronchoalveolar fluid lavage in the early stage after inhalation injury.