Protective Effect of CardioPhase on Lipid Peroxidation Related to Myocardial Necrosis

Du Xiao-yang, Li Guang-yuan, Ren Ying-yun, Cheng Xiao-li
Xinrong research group, School of Medicine, Xi’an Jiaotong University, Xi’an 710061, China

Abstract: The purpose of the present study was to assess the therapeutic effect of CardioPhase on oxidative damage associated with ischemia. Lipid peroxidation arising from ischemia has been implicated in myocardial membrane damage and cell death. CardioPhase is an herbal formulation previously shown to protect myocytes from injury during ischemia. In the present study we establish a model of rat myocardial necrosis to assess the therapeutic effects of CardioPhase on lipid peroxidation and myocardial enzymes. CardioPhase was found to decrease serum levels of phosphocreatine kinase (CPK), hydroxybutyrate dehydrogenase (HBDH) and thiobarbituric acid-reactive substances (TBARS). Our findings suggest that CardioPhase enables myocardial cells to resist damage from lipid peroxidation while improving local ischemic metabolism. Our experimental observations lead us to conclude that administration of CardioPhase may alleviate myocardial anoxia and ischemia and improve myocardial function and cellular recovery following damage to heart tissues.

Materials and Methods
We randomly divided 90 male and female rats into four treatment groups. A low-dose group was treated with CardioPhase at a dose equivalent to 40 g/kg daily. A medium-dose group received the equivalent of 80 g/kg daily, and a high-dose group received a dosage equivalent to 220 g/kg daily. The fourth group served as control and received only distilled water. Following 90 days of treatment we established a model of rat myocardial necrosis based on the Roma method. In brief, isopropylarterenol, a beta-agonist agent, was given by subcutaneous injection at different doses (2 mg/kg, 4 mg/kg, 10 mg/kg) twice over an interval of 8 hours. Infusion with isopropylarterenol brought about immediate myocardial necrosis in animals, resulting in abnormal TBARS and altered activity of CPK and HBDH enzymes.

Effect of CardioPhase on Heart Weight
After giving CardioPhase to rats for 90 days we calculated the rat’s ratio of heart-weight to body-weight. Compared with the control group, no significant difference existed in CardioPhase-treated group (P>0.05) (Table 1).

Influence on TBARS and CPK / HBDH Enzymes in Serum
Our data showed significant differences (P< 0.05) in all parameters between the control group and CardioPhase-treated groups. We observed that the decrease of TBARS was proportional to changes in activity of CPK and HBDH following myocardial necrosis. TBARS values and CPK, HBDH activity were significantly lower in serum of the CardioPhase treated groups than in the control group (P< 0.05 or P<0.01) following administration of isopropylarterenol (Table 2). These results suggest that CardioPhase can prevent or alleviate myocardial anoxia and ischemia induced by isopropylarterenol and protect cardiac muscle from damage induced by lipid peroxide.

Dose-Effect Relationship of CardioPhase and Isopropylarterenol on TBARS
Following administration of isopropylarterenol serum levels of TBARS were significantly lower in the CardioPhase-treated rats than those in the control group, illustrating that the dose-effect relationship of CardioPhase is similar to that of isopropylarterenol. There was significant difference (P< 0.001) between low dose and contrast groups, indicating that CardioPhase effectively lowers lipid peroxidation and TBARS in plasma (Table 3).

Discussion
A great many free radicals are released when phospholipases are activated in the wake of myocardial necrosis induced by isopropylarterenol. This in turn leads to the loss of radical scavenging in ischemic tissues and results in tissue injury.

In evaluating the protective function of CardioPhase on laboratory myocardial necrosis we observed that the area, quality and extent of myocardial necrosis in the CardioPhase-treated groups were significantly lower than those in the control group. We also measured significant increases in serum concentrations of reductive glutathione (GSH) in serum. Additionally we noted that CardioPhase markedly increased serum concentrations of Vitamin E. Both GSH and vitamin E serve as important intracellular antioxidants that protect heart cell membranes from damage caused by free radicals and lipid peroxides.

Long-Term Administration
Rats treated with CardioPhase for 3 months revealed no significant differences in heart-to-body-weight ratio when compared to normal rats (P>0.05). The fact that these animals grew well indicates that long-term use of oral CardioPhase has no adverse effect on heart tissues. We also observed the appearance of focal myocardial necrosis in rats not receiving CardioPhase, as well as significant increases in CPK, HBDA and TBARS values.

By contrast, CPK, HBDA and TBARS in rats receiving CardioPhase were much lower than the contrast group, demonstrating that long-term administration of CardioPhase aids in preventing the formation of lipid peroxides while reducing lipid peroxide concentrations.

Dosage
We observed that when isopropylarterenol was injected in doses 2~5 times the baseline dose, the TBARS value in rat plasma was remarkably reduced by corresponding doses of CardioPhase (i.e., 2~5 times matched increases in oral dose). This illustrates that administration of CardioPhase at doses corresponding to the extent of myocardial necrosis can effectively alleviate the extent of tissue damage. Therefore, as long as the appropriate dose-effect relationship is determined, CardioPhase can play a part in preventing or repairing myocardial necrosis.

Summary
CardioPhase has been shown to enhance the body’s free radical scavenging ability in ischemic tissues and alleviate the extent of myocardial necrosis. Test results revealed that phosphocreatine kinase (CPK), hydroxybutyrate dehydrogenase (HBDH), and thiobarbituric acid-reactive substances (TBARS) serum values were significantly decreased in animals treated with CardioPhase, indicating that CardioPhase exerts an anti-lipid peroxidation effect to maintain membrane integrity in myocardial cells while preventing cellular leakage. CardioPhase was also shown to improve local metabolism in ischemic tissues. Our experimental observations lead us to conclude that administration of CardioPhase may alleviate myocardial anoxia and ischemia and improve myocardial function and cellular recovery following damage to heart tissues.

Acknowledgements
This work was supported by 323 Hospital of PLA. The author would like to thank Dean Xi Guang-zeng.

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