The effect of gypenosides on adriamycin-induced diaphragmatic contractile function and mitochondrial ultrastructure

Objective:To study the influence of gypenosides(GP) on the diaphragmatic contractile function and mitochondrial ultrastructure induced by adriamycin(ADM) in rats.Methods:Twenty-four adult male Sprague-Dawley rats were randomly divided into control(CON)group,adriamycin diaphragm toxicity(ADM) group and adriamycin plus gypenosides(ADM+GP) group.Each group consisted of 8 rats.ADM group and ADM+GP group were injected 2.0 mg/kg ADM intraperitoneally for 6 times every other day,and CON group were injected saline of the same volume and received 250 mg/kg gypenosides per day orally in a dose of 10 ml/kg for four weeks.Meanwhile,pure water was given to ADM group and CON group.The diaphragm contractility was assessed by peak twitch tension(Pt),maximum tetanic tension(Po),time to peak contraction(CT),half relaxation time(1/2RT),and force-frequency curve by in vitro perfusion of diaphragm strips.The activity of SOD,SDH and the content of MDA were determined.The microchondrial ultrastructures of diaphragm were examined by electron microscope.Results:Compared with CON group,Pt and Po of ADM group were lower(P<0.05 to P<0.01),but Pt and Po of ADM+GP group were significantly higher than those of ADM group(P<0.05 to P<0.01); CT and 1/2RT were significant different between ADM+GP group and CON group.Compared with CON group,the tetanic force under the stimulus frequency of 10,20,40,60,80,100 Hz in ADM group and ADM+GP group decreased significantly.Under the stimulus frequency of 80 and 100 Hz,the tetanic force in ADM+GP group was higher than that in ADM group(P<0.05 to P<0.01).The activities of SOD and SDH in ADM group were lower than those in CON group and ADM+GP group(P<0.05 to P<0.01),while the content of MDA in ADM group was remarkably higher(P<0.01).Transmission electron microscopic morphometry showed that gypenosides could ease the diaphragm microchondrial ultrastructural patho-alteration induced by ADM.Conclusions:Gypenosides may lessen the injury of the diaphragmatic contractile function and mitochondrial ultrastructure induced by ADM.