The Research On Hematoporphyrin Promoting Apoptosis Activated By Ultrasound In Cardiomyocytes Of Neonatal Rat

Objective To investigate the effect of hematoporphyrin activated by ultrasound in cardiomyocytes of neonatal SD rat and to explore the mechanism .Methods The primary cultured cardiomyocytes of neonatal rat were randomly divided into four groups as follows:ultrasound(frequency 300 kHz,sound intensity 1.5 W/cm~2,irradiation 60 s) plus hematoporphyrin(concentration 20μg/ml),ultrasound(frequency 300 kHz,sound intensity 1.5 W/cm~2,irradiation 60 s),hematoporphyrin(concentration 20μg/ml) and control group. The cell growth inhibitory effect of each group was observed by MTT assay. Apoptosis was measured by flowcytometry Annexin V-FITC/PI staining methods. The expression of Fas and FasL protein were identified by immunocytochemistry.Results The cell inhibitory rates (%) of the primary cultured cardiomyocytes of neonatl rat at 24 h after treatment were ultrasound plus hematoporphyrin group 44.43,ultrasound group 35.12, hematoporphyrin group 4.11,control group 0 respectively observed by MTT assay. The growth of the cultured cardiomyocytes of neonatal rat was significantly inhibited by hematoporphyrin combined with ultrasound at 24 h after treatment(P<0.05) .The apoptosis rates (%) at early term were found to reach ultrasound plus hematoporphyrin group 24.21+2.77, ultrasound group 18.48+2.70, hematoporphyrin group 11.06+2.03,control group 7.71+0.66 respectively measured by Annexin V-FITC/PI assay. The apoptosis rate of ultrasound plus hematoporphyrin group at early term was obviously higher than those of other groups measured by Annexin V-FITC/PI assay(P<0.05).The optical density of Fas protein expression were ultrasound plus hematoporphyrin group 0.081+0.003, ultrasound group 0.061+0.006, hematoporphyrin group 0.050+0.004, control group 0.045+0.004 and the optical density of FasL protein expression were ultrasound plus hematoporphyrin group 0.080+0.002, ultrasound group 0.062+0.004, hematoporphyrin group 0.036+0.005, control group 0.034+0.002 in each group. Differences during ultrasound plus hematoporphyrin and other groups were significant (P<0.05). Compared to each group,hematoporphyrin combined with ultrasound apparently increased the level of Fas /FasL protein (P<0.05). Conclution The apoptosis of ultrasound irradiating hematoporphyrin in cardiomyocytes of neonatal rat was apparent ,and it was possibly associated with the higher expression of Fas /FasL protein .