Hepatoprotective effect of lotus leaf against non-alcoholic fatty liver disease in rats via alteration of AMPK/SIRT1 and Nrf2/HO-1 signaling pathway

Abstract

Purpose: In this study, we scrutinized the protective effect of lotus leaf (LF) against high-fat diet (HFD) induced liver injury in rats.

Methods: The rats received the HFD for the induction of non-alcoholic fatty liver disease. Rats received the oral administration of LF (25, 50, and 100 mg/kg, b.w.). The insulin level, organ index, glucose level, hepatic, oxidative stress, lipid and cytokines parameters were measured. The different mRNA expression and histopathology were performed in the hepatic tissue.

Results: LF treatment suppressed the insulin, glucose and HOMA-IR along with organ index (liver index and spleen index). LF treatment altered the level of liver parameters (aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, gamma-glutamyl transferase) and oxidative stress parameters in the serum, as well as the liver tissue. LF treatment altered the level of lipid parameters and fat parameters (total fat, perirenal fat, abdominal fat, epididymal fat); cytokines (tumor necrosis factor-α, interleukin-1β, interleukin-6, interleukin-10, interleukin-17, interleukin-33); HO-1, and Nrf2. LF treatment altered the mRNA expression of tumor necrosis factor-α, interleukin-1β, interleukin-6, interleukin-10, caspase-3, caspase-9, cytochrome C, cytochrome D, AMP-activated protein kinase (AMPK), sirtuin 1 (SIRT1), FRX-1, liver X Receptor alpha, fibronectin, matrix metalloproteinase-9, inducible nitric oxide synthase, and transforming growth factor-β 1 (TGF-β1). LF treatment suppressed the necrosis of hepatocytes with less inflammatory cell infiltration in the liver tissue along with alteration of liver injury score.

Conclusion: The result showed the protective effect of LF against non-alcoholic fatty liver disease via activating the AMPK/SIRT1 and Nrf2/HO-1 pathway activation.

Figure 1. Effect of lotus (Nelumbo nucifera) leaf extract on the (a) serum insulin, (b) blood glucose level and (c) HOMAIR against non-alcoholic fatty liver disease in rats. All data are presented as mean ± standard error of the mean.

Figure 2. Effect of lotus (Nelumbo nucifera) leaf extract on (a) the liver index and (b) spleen index against non-alcoholic fatty liver disease in rats. All data are presented as mean ± standard error of the mean.

Figure 3. Effect of lotus (Nelumbo nucifera) leaf extract on the level of hepatic parameters against non-alcoholic fatty liver disease in rats. (a) alanine aminotransferase (ALT) in serum, (b) aspartate aminotransferase (AST) in serum, (c) alkaline phosphatase (ALP) in serum, (d) gamma-glutamyl transferase (γ-GT) in serum, (e) ALT, (f) AST, (g) ALP, and (h) γ-GT. All data are presented as mean ± standard error of the mean.

Figure 4. Effect of lotus (Nelumbo nucifera) leaf extract on the level of antioxidant parameters against non-alcoholic fatty liver disease in rats. (a) glutathione (GSH) in serum, (b) superoxide dismutase (SOD) in serum, (c) catalase (CAT) in serum, (d) glutathione peroxidase (GPx) in serum, (e) malonaldehyde (MDA) in serum, (f) GSH in tissue, (g) SOD in tissue, (h) CAT in tissue, (i) GPx in tissue, and (j) MDA in tissue. All data are presented as mean ± standard error of the mean.

Figure 5. Effect of lotus (Nelumbo nucifera) leaf extract on the level of lipid parameters against non-alcoholic fatty liver disease in rats. (a) total cholesterol (TC), (b) triglyceride (TG), (c) high density lipoprotein (HDL), (d) low density lipoprotein (LDL), (e) very low-density lipoprotein (VLDL). All data are presented as mean ± standard error of the mean.

Figure 6. Effect of lotus (Nelumbo nucifera) leaf extract on the level of fat parameters against non-alcoholic fatty liver disease in rats. (a) Total fat, (b) perirenal fat, (c) abdominal fat, (d) epididymal fat. All data are presented as mean ± standard error of the mean.

Figure 7. Effect of lotus (Nelumbo nucifera) leaf extract on the level of inflammatory cytokines parameters against non-alcoholic fatty liver disease in rats. (a) Tumor necrosis factor-α (TNF-α), (b) interleukin- (IL)-1β, (c) IL-6, (d) IL-17, (e) IL-33. All data are presented as mean ± standard error of the mean.

Figure 8. Effect of lotus (Nelumbo nucifera) leaf extract on the level of (a) heme oxygenase 1 (HO-1) and (b) nuclear factor erythroid 2-related factor (Nrf₂) against non-alcoholic fatty liver disease in rats. All data are presented as mean ± standard error of the mean.

Figure 9. Effect of lotus (Nelumbo nucifera) leaf extract on the mRNA expression of inflammatory cytokines parameters against non-alcoholic fatty liver disease in rats. (a) Tumor necrosis factor-α (TNF-α), (b) interleukin- (IL)-1β, (c) IL-6, (d) IL-10. All data are presented as mean ± standard error of the mean.

Figure 10. Effect of lotus (Nelumbo nucifera) leaf extract on the mRNA of (a) caspase-3, (b) caspase-9, (c) Cyt-C and (d) Cyt-D against non-alcoholic fatty liver disease in rats. All data are presented as mean ± standard deviation of the mean.

Figure 11. Effect of lotus (Nelumbo nucifera) leaf extract on the mRNA expression of (a) AMP-activated protein kinase (AMPK), (b) sirtuin 1 (SIRT-1), (c) FBX-1, (d) liver X receptor alpha (LXR-α), (e) fibronectin and (f) matrix metalloproteinase-9 (MMP-9) against non-alcoholic fatty liver disease in rats. All data are presented as mean ± standard error of the mean.

Figure 12. Effect of lotus (Nelumbo nucifera) leaf extract on the mRNA expression of (a) inducible nitric oxide synthase (iNOS), (b) transforming growth factor-β1 (TGF-β1), (c) heme oxygenase-1 (HO-1), and (d) nuclear factor erythroid 2-related factor 2 (Nrf₂) against non-alcoholic fatty liver disease in rats. All data are presented as mean ± standard error of the mean.

Figure 13. Effect of lotus (Nelumbo nucifera) leaf extract on (a) the liver histopathology and (b) liver injury against non-alcoholic fatty liver disease in rats. All data are presented as mean ± standard error of the mean.