AIM： To investigate the structural and biochemical changes in the early stage of reperfusion in the rat livers exposed to lobar ischemia-reperfusion （IR）. METHODS： The median and left lobes of the liver were subje...AIM： To investigate the structural and biochemical changes in the early stage of reperfusion in the rat livers exposed to lobar ischemia-reperfusion （IR）. METHODS： The median and left lobes of the liver were subjected to 60 min ischemia followed by 5, 10, 30, 45, 60 and 120 min reperfusion. Blood samples were taken at different time intervals to test enzyme activities and biochemical alterations induced by reperfusion. At the end of each reperfusion period, the animals were killed by euthanasia and tissue samples were taken for histological examination and immunohistochemistry. RESULTS： Cell vacuolation, bleb formation and focal hepatitis were the most important changes occur during ischemia. While some changes including bleb formation were removed during reperfusion, other alterations including portal hepatitis, inflammation and the induction of apoptosis were seen during this stage. The occurrence of apoptosis, as demonstrated by apoptotic cells and bodies, was the most important histological change during reperfusion. The severity of apoptosis was dependent on the time of reperfusion, and by increasing the time of reperfusion, the numbers of apoptotic bodies was significantly enhanced. The amounts of lactate dehydrogenase, alanine aminotransferase, aspartate aminotransfrase, creatinine and urea were significantly increased in serum obtained from animals exposed to hepatic IR. CONCLUSION： Inflammation and subsequent apoptotic cell death were the most important changes in early-stage hepatic reperfusion injury, and the number of apoptotic bodies increased with time of reperfusion.展开更多
To explore the molecular mechanism of chromatin remodeling involved in the regulation of transcriptional activation of specific genes by a myogenic regulatory factor Myogenin, we used NIH3T3 fibroblasts with a stably ...To explore the molecular mechanism of chromatin remodeling involved in the regulation of transcriptional activation of specific genes by a myogenic regulatory factor Myogenin, we used NIH3T3 fibroblasts with a stably integrated Hl.l-GFP fusion protein to monitor histone HI movement directly by fluorescence recovery after photobleaching (FRAP) in living cells. The observation from FRAP experiments with myogenin transfected fibroblasts showed that the exchange rate of histone HI in chromatin was obviously increased, indicating that forced expression of exogenous Myogenin can induce chromatin remodeling. The hyper-acetylation of histones H3 and H4 from myogenin transfected fibroblasts was detected by triton-acid-urea (TAU)/SDS (2-D) electrophoresis and Western blot with specific antibodies against acetylated N-termini of histones H3 and H4. RT-PCR analysis indicated that the nAChR β-subunit gene was expressed in the transfected fibroblasts. These results suggest that the expression of exogenous Myogenin can induce chromatin remodeling and activate the transcription of Myogenin-targeted gene in non-muscle cells.展开更多
基金Supported by University of Tehran,Vice chancellor forresearch and technology
文摘AIM： To investigate the structural and biochemical changes in the early stage of reperfusion in the rat livers exposed to lobar ischemia-reperfusion （IR）. METHODS： The median and left lobes of the liver were subjected to 60 min ischemia followed by 5, 10, 30, 45, 60 and 120 min reperfusion. Blood samples were taken at different time intervals to test enzyme activities and biochemical alterations induced by reperfusion. At the end of each reperfusion period, the animals were killed by euthanasia and tissue samples were taken for histological examination and immunohistochemistry. RESULTS： Cell vacuolation, bleb formation and focal hepatitis were the most important changes occur during ischemia. While some changes including bleb formation were removed during reperfusion, other alterations including portal hepatitis, inflammation and the induction of apoptosis were seen during this stage. The occurrence of apoptosis, as demonstrated by apoptotic cells and bodies, was the most important histological change during reperfusion. The severity of apoptosis was dependent on the time of reperfusion, and by increasing the time of reperfusion, the numbers of apoptotic bodies was significantly enhanced. The amounts of lactate dehydrogenase, alanine aminotransferase, aspartate aminotransfrase, creatinine and urea were significantly increased in serum obtained from animals exposed to hepatic IR. CONCLUSION： Inflammation and subsequent apoptotic cell death were the most important changes in early-stage hepatic reperfusion injury, and the number of apoptotic bodies increased with time of reperfusion.
文摘To explore the molecular mechanism of chromatin remodeling involved in the regulation of transcriptional activation of specific genes by a myogenic regulatory factor Myogenin, we used NIH3T3 fibroblasts with a stably integrated Hl.l-GFP fusion protein to monitor histone HI movement directly by fluorescence recovery after photobleaching (FRAP) in living cells. The observation from FRAP experiments with myogenin transfected fibroblasts showed that the exchange rate of histone HI in chromatin was obviously increased, indicating that forced expression of exogenous Myogenin can induce chromatin remodeling. The hyper-acetylation of histones H3 and H4 from myogenin transfected fibroblasts was detected by triton-acid-urea (TAU)/SDS (2-D) electrophoresis and Western blot with specific antibodies against acetylated N-termini of histones H3 and H4. RT-PCR analysis indicated that the nAChR β-subunit gene was expressed in the transfected fibroblasts. These results suggest that the expression of exogenous Myogenin can induce chromatin remodeling and activate the transcription of Myogenin-targeted gene in non-muscle cells.
