Cardiac protection of germinated brown rice extract in rabbit model of chronic myocardial infarction

Arsenic in brown rice: do the benefits outweigh the risks?

Brown rice has been advocated for as a healthier alternative to white rice. However, the concentration of arsenic and other pesticide contaminants is greater in brown rice than in white. The potential health risks and benefits of consuming more brown rice than white rice remain unclear; thus, mainstream nutritional messaging should not advocate for brown rice over white rice. This mini-review aims to summarize the most salient concepts related to dietary arsenic exposure with emphasis on more recent findings and provide consumers with evidence of both risks and benefits of consuming more brown rice than white rice. Despite risk-benefit assessments being a challenging new frontier in nutrition, researchers should pursue an assessment to validate findings and solidify evidence. In the interim, consumers should be cognizant that the dose of arsenic exposure determines its toxicity, and brown rice contains a greater concentration of arsenic than white rice.

White rice ethanol extract is qualitatively, but not quantitatively, equivalent to that of brown rice as an antioxidant source

The purpose of this study is to compare the potentials to exhibit biologically active antioxidant actions between white rice (WR) and brown rice (BR) in in vitro assays and a cellular model. The Trolox equivalent (TE) per 1 mg ethanol extract of WR for the 1,1-diphenyl-2-picrylhydrazyl assay was slightly higher than that of BR, whereas the TE per 1 g whole WR was much lower than that for BR. This tendency was very comparable to those for the oxygen radical absorbance capacity and total polyphenol content. Both of the ethanol extracts also similarly suppressed the hydrogen peroxide-induced cytotoxicity and enhanced the gene expression of drug-metabolizing enzymes. Based on the α-tocopherol quantity, its contribution to the cytoprotective effect of the rice extracts is very limited. Taken together, the ethanol extract of WR might be a qualitatively, but not quantitatively, equivalent source of antioxidative phytochemicals to that of BR.

A Cardiac Protection of Germinated Brown Rice During Cardiopulmonary Bypass Surgery and Simulated Myocardial Ischemia

Purpose

The potential cardio-protective property of germinated brown rice (GBR) has been revealed by ameliorating risk factors related to cardiovascular diseases. This study hypothesized that the combination of GBR and cardioplegic solution could protect the cardiomyocytes exposed to simulated ischemic reperfusion injury in vitro study and preserve cardiac function during cardiopulmonary bypass surgery in animal models.

Methods

Primary porcine cardiomyocytes were isolated and experimented cell viability against simulated ischemic reperfusion injury. In a cardiac surgical animal model, six pigs were randomly assigned to receive the two types of cardioplegic solution: i) St. Thomas cardioplegic solution (20 cc/kg); and ii) St. Thomas cardioplegic solution plus GBR (1 mg/kg). During open-heart surgery, the aorta was cross-clamped for 20 minutes, followed by reperfusion for 1 hour. Cardiopulmonary bypass parameters were recorded until the end of the procedure. Furthermore, hemodynamic parameters and arterial blood gas characteristics of animals among groups were monitored at different time points, including baseline before cardiopulmonary bypass (T1), during cardiopulmonary bypass (T2), during aortic clamp on (T3), and aortic clamp off (T4).

Results

Primarily, GBR cotreatment with cardioplegic solution essentially resulted in the improvement of cell viability in primary porcine cardiomyocytes against simulated ischemic reperfusion induction. The findings from cardiac surgery demonstrated that mean arterial pressure and heart rate are constantly stable in cardioplegic solution combined with the GBR group, while the trend of potassium and lactase concentration was decreased in the animals receiving GBR group. Consistently, all parameters from arterial blood gas showed better outcomes in animals receiving GBR; however, there were no statistically significant differences between groups, except hepatic enzymes.

Conclusion

Therefore, GBR might exert cardio-protective effects against ischemic reperfusion injury in the porcine cardiac surgery model due to anti-inflammatory response. These protective actions of GBR may explain the benefits gained from applying GBR products as a possible therapeutic supplement on cardiac diseases.

Bioactive Compounds from Germinated Brown Rice Protect Cardiomyocytes Against Simulated Ischemic/Reperfusion Injury by Ameliorating Mitochondrial Dysfunction

Purpose

Ischemic/reperfusion (I/R) injury is the principal mechanism during Ischemic Heart Disease (IHD). The key modulator of I/R injury is dysregulation of mitochondria function. Germinated Brown Rice (GBR) has been recommended as a bio-functional food and has clarified the potential properties in several effects. However, the effect of GBR mediated cardioprotective properties, focusing on mitochondrial function’s role, remains unexplored. Thus, this study aims to investigate the cardioprotective effects of GBR pretreatment against simulated I/R injury.

Methods

H9c2 cardiomyocytes were incubated with GBR at a five ƞg/mL concentration for 24 hours and simulated I/R (sI/R) for 40 minutes. Cell viability and cell apoptosis were assessed by 7-AAD staining and Annexin V/PI staining, respectively. The mitochondrial membrane potential was determined by JC-1 staining and mitochondrial respiration represented by oxygen consumption rate (OCR) using Seahorse Flux analyzer.

Results

The results revealed that the administration of GBR before sI/R significantly decreased the percentage of cell death and total cell apoptosis in H9c2 during stimulation of ischemic/reperfusion. Besides, pretreatment of cardiomyocytes with GBR remarkably stabilized mitochondrial membrane potential and improved impaired mitochondrial respiration in simulated-H9c2 injury.

Conclusion

The present research is the first study to report the effective cardioprotection of GBR. Pretreatment of GBR potentially protects H9c2 cardiomyocytes against sI/R injury through mitochondrial function. The underlying therapeutic activities are possibly associated with its bio-functional compounds. However, the underlying mechanism on the cardioprotective effects of GBR needs further studies.