ABSTRACT
AIM:To investigate the inhibitory effect of ethanol extract of propolis (EEP) on oxidized low-density lipoprotein (ox-LDL)-induced vascular endothelial cell apoptosis and the underlying molecular mechanisms.METHODS:Human umbilical vein endothelial cells (HUVECs) were pretreated with EEP (7.5,15 and 30 mg/L) or 4-phenylbutyric acid (PBA,4 mmol/L) for 1 h and then treated with ox-LDL (100 mg/L) or tunicamycin (TM,4 mg/L) for 24 h.The cell viability and apoptosis were determined by MTT assay and Annexin V-FITC/PI double staining,respectively.The activities of lactic dehydrogenase (LDH) in the medium and caspase-3 in the HUVECs were measured.The protein and mRNA levels of C/EBP homologous protein (CHOP),a proapoptotic molecule under endoplasmic reticulum stress (ERS),and its downstream Bcl-2 were examined by Western blot and real-time PCR,respectively.RESULTS:Like PBA (an ERS inhibitor),EEP protected HUVECs from ox-LDL-induced injury in a dose-dependent manner,as assessed by the increased cell viability and the decreased LDH release,apoptotic rate and caspase-3 activation.The decrease in cell viability and the increases in LDH release,apoptotic rate and caspase-3 activation induced by TM,an ERS inducer,were also attenuated by EEP.Moreover,EEP suppressed ox-LDL-induced CHOP upregulation and Bcl-2 downregulation,and this effect was similar to that of PBA.Similarly,EEP significantly suppressed TM-induced CHOP upregulation both at the protein and mRNA levels.CONCLUSION:EEP may protect HUVECs from ox-LDL-induced apoptosis,and the mechanism is at least partially involved in suppressing CHOP-mediated ERS-associated apoptotic pathway.
ABSTRACT
AIM:To investigate the inhibitory effect of ethanol extract of propolis (EEP) on oxidized low-density lipoprotein (ox-LDL)-induced vascular endothelial cell apoptosis and the underlying molecular mechanisms.METHODS:Human umbilical vein endothelial cells (HUVECs) were pretreated with EEP (7.5,15 and 30 mg/L) or 4-phenylbutyric acid (PBA,4 mmol/L) for 1 h and then treated with ox-LDL (100 mg/L) or tunicamycin (TM,4 mg/L) for 24 h.The cell viability and apoptosis were determined by MTT assay and Annexin V-FITC/PI double staining,respectively.The activities of lactic dehydrogenase (LDH) in the medium and caspase-3 in the HUVECs were measured.The protein and mRNA levels of C/EBP homologous protein (CHOP),a proapoptotic molecule under endoplasmic reticulum stress (ERS),and its downstream Bcl-2 were examined by Western blot and real-time PCR,respectively.RESULTS:Like PBA (an ERS inhibitor),EEP protected HUVECs from ox-LDL-induced injury in a dose-dependent manner,as assessed by the increased cell viability and the decreased LDH release,apoptotic rate and caspase-3 activation.The decrease in cell viability and the increases in LDH release,apoptotic rate and caspase-3 activation induced by TM,an ERS inducer,were also attenuated by EEP.Moreover,EEP suppressed ox-LDL-induced CHOP upregulation and Bcl-2 downregulation,and this effect was similar to that of PBA.Similarly,EEP significantly suppressed TM-induced CHOP upregulation both at the protein and mRNA levels.CONCLUSION:EEP may protect HUVECs from ox-LDL-induced apoptosis,and the mechanism is at least partially involved in suppressing CHOP-mediated ERS-associated apoptotic pathway.
ABSTRACT
Pseudomonas aeruginosa es un bacilo Gram negativo no fermentador de glucosa comúnmente aislado en infecciones nosocomiales. El incremento de la resistencia a los antibióticos y la participación de este microorganismo en patologías que cursan con formación de biopelículas da como resultado la falla usual de los antimicrobianos, por lo que resulta interesante estudiar el extracto etanólico de propóleos (EEP) como alternativa terapéutica frente a este patógeno oportunista. En este sentido, el objetivo principal del estudio fue evaluar el efecto del EEP sobre Pseudomonas aeruginosa en estado planctónico y sésil. El estudio se enmarcó en una investigación de tipo descriptiva, cuasi-experimental. Se determinó la concentración mínima inhibitoria (CMI) y bactericida (CMB) en estado planctónico por el método de macrodilución en tubos y en estado sésil por microdilución sobre biopelículas formadas en placas de poliestireno. Los resultados mostraron que el EEP, posee actividad bacteriostática parcial pero no total a 4% y actividad bactericida a 8% sobre P. aeruginosa en estado planctónico. Mientras que en estado sésil no hubo efecto bacteriostático ni bactericida. Se concluye que el EEP del Edo. Táchira Venezuela es efectivo frente a P. aeruginosa en estado planctónico pero no tiene actividad antimicrobiana sobre biopelículas formadas por la misma especie.
Pseudomonas aeruginosa is a glucose non-fermenting Gram-negative bacillus that is commonly isolated in nosocomial infections. The usual antimicrobials failure is the result of the increase in antibiotics resistance and this microorganisms involvement in pathologies with biofilm formation. Therefore, the ethanol extract of propolis becomes an interesting subject of study as a therapeutic alternative against this opportunist pathogen. In this regard, the main objective of this investigation was to evaluate the effect of ethanol extract of propolis (EEP) over Pseudomonas aeruginosa in planktonic and sessile state. This research was categorized as a descriptive quasi-experimental type of investigation. It was determined the minimum inhibitory (MIC) and bactericide (MBC) concentration by the macrodilution tubes method in planktonic state, and the microdilution over biofilms formed on polystyrene plates in sessile state. The results showed that whereas there wasnt a bacteriostatic or bactericide effect in sessile state, the EEP possesses 4% of non total but partial bacteriostatic activity and 8% of bactericide activity over P. aeruginosa in planktonic state. It concludes that the EEP of the Venezuelan state of Táchira is effective against P. aeruginosa in planktonic state but it wont have antimicrobial activity over biofilms formed by the same species.
ABSTRACT
AIM:To investigate the inhibitory effect of ethanol extract of propolis (EEP) on oxidized low-den-sity lipoprotein ( ox-LDL )-induced macrophage apoptosis and the underlying molecular mechanisms . METHODS:RAW264.7 macrophages were pretreated with EEP (7.5, 15 and 30 mg/L), 4-phenylbutyric acid (PBA, 5 mmol/L) or diphenyleneiodonium ( DPI, 5μmol/L) for 1 h and then treated with ox-LDL (100 mg/L) or tunicamycin ( TM, 4 mg/L) for 24 h.The cell viability and apoptosis were determined by MTT assay and Annexin V-FITC apoptosis detection kit , re-spectively.The activity of superoxide dismutase (SOD), and the levels of reactive oxygen species (ROS) and malondial-dehyde (MDA) in the cells were measured.The protein levels of caspase-12, a proapoptotic molecule under endoplasmic reticulum stress ( ERS) , were examined by Western blot analysis .RESULTS:Like PBA ( an ERS inhibitor ) , EEP pro-tected RAW264.7 macrophages from ox-LDL-induced injury in a dose-dependent manner , as assessed by the increased cell viability and the decreased apoptotic rate .The decrease in cell viability and increase in apoptotic rate induced by TM , an ERS inducer, were also attenuated by EEP .Moreover, EEP suppressed ox-LDL-induced oxidative stress as revealed by the decreased generation of ROS and MDA as well as elevated SOD activity , which were similar to DPI , an oxidative stress in-hibitor.Furthermore, EEP significantly suppressed ox-LDL-or TM-induced activation of caspase-12.Similar results were observed in the cells pretreated with PBA or DPI and then treated with ox-LDL.CONCLUSION: EEP may protect RAW264.7 macrophages from ox-LDL-induced apoptosis and the mechanism is at least partially involved in the ability of EEP to suppress oxidative stress and subsequent activation of caspase -12.