Rikkunshito (TJ-43) Improved Reduction of Food Intake in a Murine Cardiac Transplantation Model

Japanese Traditional Herbal Medicine, Rikkunshito, Partially Suppresses Inflammatory Responses in Myocardial Ischemia/Reperfusion Injury

INTRODUCTION

Myocardial ischemia/reperfusion (I/R) injury can cause additional damage to an ischemic myocardium, even after successful reperfusion therapy. Inflammation is a mechanism that exacerbates myocardial damage after I/R injury. Rikkunshito (RKT) is a traditional Japanese herbal medicine widely used to treat gastrointestinal symptoms. It attenuates inflammation and fibrosis in some diseases of the heart; however, it remains unclear whether RKT exerts cardioprotective effects against myocardial I/R injury. To elucidate this, we evaluated the effects of RKT pre-treatment by oral administration on the myocardium in a mouse model of in vivo I/R injury.

METHODS

Mice were randomly assigned to a group receiving distilled water (DW) or one receiving RKT (1000 mg/kg/day) for 14 days orally. For each of the RKT and DW groups, a sham group, an I/R 2 h group, and an I/R 24 h group were created. On day 15, myocardial I/R surgery was performed. The left anterior descending coronary artery (LAD) was ligated for 30 min, and reperfusion time was set at 2 h or 24 h. The myocardial infarct size (IS) was measured after 2 h of reperfusion, and cardiac cytokine mRNA expression levels were evaluated by quantitative reverse transcription polymerase chain reaction (RT-PCR) after 2 h and 24 h of reperfusion.

RESULTS

RKT pre-treatment significantly suppressed the cardiac mRNA expression level of interleukin-1β in the RKT-I/R 2 h group compared to the DW-I/R 2 h group (P < 0.05). Additionally, RKT significantly suppressed the mRNA expression levels of transforming growth factor-β compared to DW; the same result was obtained for the expression levels of interleukin-6. However, RKT did not reduce the IS or mRNA expression levels of the cardiac congestive markers natriuretic peptide a (NPPA) and natriuretic peptide b (NPPB). In addition, RKT did not alter the plasma concentration of ghrelin and sirtuin 1 (Sirt1), which have been reported to be stimulated by RKT.

CONCLUSION

This study showed that pre-treatment of RKT for myocardial I/R injury partially suppressed inflammation-related cytokines. However, further studies are needed on the effect of RKT on the reduction of myocardial infarction size.

Ghrelin May Inhibit Inflammatory Response and Apoptosis During Ischemia-Reperfusion Injury

BACKGROUND

Ghrelin, a novel growth hormone-releasing peptide, has both anti-inflammatory and anti-apoptotic effects on human endothelial cells. We evaluated the protective effects of ghrelin against ischemia-reperfusion injury (IRI) in a murine heterotopic cervical heart transplantation model.

METHODS

Donor hearts from C57BL/6J wild-type mice, which were kept in cold saline for 60 minutes, were heterotopically transplanted into C57BL/6J wild-type recipients. A day prior to heterotopic cervical heart transplantation, donor animals received either ghrelin (300 nmol/kg) or saline (0.3 mL) intraperitoneally. Upon reperfusion and postoperative day 1, ghrelin or saline was administered to the recipients. Donor hearts were procured on day 2.

RESULTS

Ghrelin injection did not result in any adverse effects in donors or recipients. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling-positive cells were significantly decreased in the ghrelin group (0.38% ± 0.21% vs 5.74% ± 3.68%; P < .001). Both cleaved caspase-3 activity and Bcl-2/Bax ratio from the ghrelin group were significantly reduced compared to those in the control. Furthermore, the phosphorylated Akt/Akt ratio was higher in the ghrelin group (0.44 ± 0.21 vs 0.14 ± 0.03; P = .043). Nuclear factor-kappa B p65 nuclear translocation was reduced in the ghrelin hearts compared to the controls (3.17% ± 1.84% vs 19.28% ± 13.14%; P = .009). Vascular cell adhesion molecule-1, intracellular adhesion molecule-1, nuclear factor-kappa B, and tumor necrosis factor alpha levels were also significantly reduced in the ghrelin-treated group. No significant difference was observed in 8-isoprostane production between groups.

CONCLUSION

Ghrelin inhibits the inflammatory response and apoptosis during transplant-related IRI. This study demonstrates the protective effects of ghrelin against IRI.

Effects of rikkunshito on renal fibrosis and inflammation in angiotensin II-infused mice

The underlying pathogenesis of chronic kidney disease involves an activated renin-angiotensin system and systemic inflammation which ultimately develop renal injury. Rikkunshito (RKT) has been reported to exert anti-fibrotic and anti-inflammatory effects through enhancement of ghrelin signaling pathway. In this study, we investigated the effects of RKT on renal fibrosis and inflammation in angiotensin II (Ang II)-induced renal injury model. Ang II-infused mice exhibited hypertension, cardiac hypertrophy, increases in blood urea nitrogen and serum creatinine, moderate albuminuria and renal pathological changes such as mild urinary cast, interstitial macrophage infiltration and modest interstitial fibrosis. RKT had no evident effects on the Ang II-induced renal functional insufficiency and fibrosis, but attenuated renal interstitial macrophage infiltration. In addition, RKT significantly restored the Ang II-induced alteration in the expression of renal fibrosis- and inflammation-related genes such as type 3 collagen, transforming growth factor-β, monocyte chemoattractant protein-1 and interleukin-6. Furthermore, although RKT did not affect the expression of renal ghrelin receptor, an Ang II-induced decrease in renal sirtuin 1 expression, a critical down-stream pathway of the ghrelin receptor, was restored by RKT. These findings suggest that RKT potentially has a renal anti-inflammatory effect in the development of renal injury, and this effect could be mediated by the ghrelin signaling pathway.