ABSTRACT
<p><b>AIM</b>To detect effect of the different frequency of chronic electrical stimulation (CES) on myofibrillar isoform, myosin heavy chain (MHC) and metabolic enzyme activities.</p><p><b>METHODS</b>The histochemical method and SDS-polyacrylamide gel electrophoresis were respectively employed.</p><p><b>RESULTS</b>(1)There were a significant increase in I myo-fibrillar isoform and I MHC isoform and decrease in II B myofibrillar isoform and II B MHC isoforms in the chronic low frequency electrical stimulation (CLFES) 10 Hz and 20 Hz groups, but opposite results were found in the chronic high frequency electrical stimulation (CHFES) 50 Hz and 100 Hz groups. (2) There were a significant increase in the aerobic-oxidative enzyme activities and capacity, and a concomitant significant drop in glycolysis enzyme activities in CLFES groups, but opposite results were found in CHFES 50 Hz and 100 Hz groups.</p><p><b>CONCLUSION</b>It was suggested that there was a significant dependent relation between chronic electrical stimulation frequency and myofibrilla isoforms, myosin heavy chain (MHC) and metabolic enzyme activities.</p>
Subject(s)
Animals , Rabbits , Adaptation, Physiological , Diaphragm , Metabolism , Physiology , Electric Stimulation , Muscle Contraction , Myosin Heavy Chains , Metabolism , Nonmuscle Myosin Type IIB , Metabolism , Protein IsoformsABSTRACT
The mRNA and protein expression of skeletal dihydropyridine receptor isoform alpha1 subunit (DHPR(alpha1)) and ryanodine receptor(1-3) (RyR(1-3)) during chronic electrical stimulation (CES) of phrenic nerve have rarely been explored. In the present study, we explored the signal translation mode of calcium release unit in diaphragm muscle of rabbits after CES. Thirty rabbits were used and randomly divided into the normal, 10, 20, 50 and 100 Hz groups. Phrenic nerve was continuously (5 weeks, 2x 2 h/d) stimulated at 10, 20, 50 and 100 Hz respectively (impulse width 0.2 ms, 3~6 waves/time, 45 times/min, 10~20 V). Reverse transcription PCR and immunohistochemical methods were employed. The results showed that mRNA and protein expressions of DHPR(alpha1) and RyR(1) in 10 and 20 Hz groups were more significantly lower than those in the control group (P<0.01), but mRNA and protein expressions of DHPR(alpha1) and RyR(1) were significantly higher in 50 and 100 Hz groups than those in the control group (P<0.01); a lower level of mRNA expression of RyR(2) was found in 10 and 20 Hz groups. It is suggested that the calcium release unit and the signal transduction mode between DHPR and RyRs were altered from conformational changes of linked proteins to Ca(2+)-induced Ca(2+) release (CICR) in the diaphragmatic muscle of rabbits after chronic low-frequency electrical stimulation of phrenic nerve for 5 weeks.
Subject(s)
Animals , Female , Male , Rabbits , Calcium , Metabolism , Calcium Channels, L-Type , Genetics , Diaphragm , Metabolism , Physiology , Electric Stimulation , Muscle, Skeletal , Metabolism , Physiology , Phrenic Nerve , Metabolism , Physiology , RNA, Messenger , Genetics , Random Allocation , Ryanodine Receptor Calcium Release Channel , GeneticsABSTRACT
Objective To study the effect of transfecting anti-sense expression vector of the first subtype of the monocarboxylate transporter (MCT1) gene into human lung adenocarcinoma cells on intracellular pH (pHi) regulation, lactate transportation and cell growth. Methods MCT1 antisense gene recombinant vector pLXSN-MCT1 was introduced into human lung cancer cells A549 with electroporation. The cell colonies resistant to G418 were selected. Positive clones were examined by PCR to confirm the integration of genomic A549 DNA and antisene MCT1 gene. The changes of pHi and lactate transportation were detected with spectrophotometry. Cell growth was studied with cell growth curve. Results pHi and lactate transport were remarkably decreased in the transfected cells, and the cell growth was inhibited compared with the cells without transfection（P<0.001）. Conclusion MCT1 gene may play an important role in pHi regulation, lactate transport and cell growth in lung tumor cells.
ABSTRACT
Objective To study the effect of transfecting anti-sense expression vector of the first subtype of the monocarboxylate transporter (MCT1) gene into human lung adenocarcinoma cells on intracellular pH (pHi) regulation, lactate transportation and cell growth. Methods MCT1 antisense gene recombinant vector pLXSN-MCT1 was introduced into human lung cancer cells A549 with electroporation. The cell colonies resistant to G418 were selected. Positive clones were examined by PCR to confirm the integration of genomic A549 DNA and antisene MCT1 gene. The changes of pHi and lactate transportation were detected with spectrophotometry. Cell growth was studied with cell growth curve. Results pHi and lactate transport were remarkably decreased in the transfected cells, and the cell growth was inhibited compared with the cells without transfection（P<0.001）. Conclusion MCT1 gene may play an important role in pHi regulation, lactate transport and cell growth in lung tumor cells.