Zingiber officinale extract maximizes the efficacy of simvastatin as a hypolipidemic drug in obese male rats

Abstract

Obesity became a serious public health problem with enormous socioeconomic implications among the Egyptian population. The present investigation aimed to explore the efficacy of Zingiber officinale extract as a hypolipidemic agent combined with the commercially well-known anti-obesity drug simvastatin in obese rats. Thirty-five male Wister rats were randomly divided into five groups as follows: group I received a standard balanced diet for ten weeks; high-fat diet was orally administered to rats in groups II-V for ten weeks. From the fifth week to the tenth week, group III orally received simvastatin (40 mg/kg B.W.), group IV orally received Z. officinale root extract (400 mg/kg B.W.), and group V orally received simvastatin (20 mg/kg B.W.) plus Z. officinale extract (200 mg/kg B.W.) separately. Liver and kidney function tests, lipid profiles, serum glucose, insulin, and leptin were determined. Quantitative RT-PCR analysis of PPAR-γ, iNOS, HMG-CoA reductase, and GLUT-4 genes was carried out. Caspase 3 was estimated in liver and kidney tissues immunohistochemically. Liver and kidney tissues were examined histologically. The administration of Z. officinale extract plus simvastatin to high-fat diet-fed rats caused a significant reduction in the expression of HMG-coA reductase and iNOS by 41.81% and 88.05%, respectively, compared to highfat diet (HFD)-fed rats that received simvastatin only. Otherwise, a significant increase was noticed in the expression of PPAR-γ and GLUT-4 by 33.3% and 138.81%, respectively, compared to those that received simvastatin only. Immunohistochemistry emphasized that a combination of Z. officinale extract plus simvastatin significantly suppressed caspase 3 in the hepatic tissue of high-fat diet-fed rats. Moreover, the best results of lipid profile indices and hormonal indicators were obtained when rats received Z. officinale extract plus simvastatin. Z. officinale extract enhanced the efficiency of simvastatin as a hypolipidemic drug in obese rats due to the high contents of flavonoid and phenolic ingredients.

Keywords: GLUT‐4; HMG‐CoA reductase; RT‐PCR; Zingiber officinale; anti‐obesity; caspase‐3.

FIGURE 1

Total flavonoids and total phenolic contents of ZING.

FIGURE 2

The effect of ZING and SIM on liver histopathology. (a) Liver of G1 animal showing normal hepatocytes around the central vein (H indicates hepatocytes and cv indicates central vein), H&E, ×200, bar = 50 μm, (b) liver of G2 animal showing diffuse marked hepatic vacuolation associated with both fatty changes (arrows) and glycogen accumulation within hepatocytes (arrowheads), H&E, ×200, bar = 50 μm, (c) liver of G3 animal showing decrease fatty changes with granular vacuolar degeneration within hepatocytes (arrow indicates fat vacuole and H indicates hepatocytes), H&E, ×200, bar = 50 μm, (d) liver of G4 animal showing decreased fatty changes with moderate degree of granular vacuolar degeneration (arrow indicates fat vacuole and H indicates hepatocytes), H&E, ×200, bar = 50 μm, (e) liver of G5 animal showing marked decrease in fat accumulation and granular changes within hepatocytes (arrows), H&E, ×200, bar = 50 μm.

FIGURE 3

The effect of ZING and SIM on kidney histopathology. (a) Kidney of a G1 animal showing normal renal glomeruli and tubules (arrowhead and arrow, respectively), H&E, ×200, bar = 50 μm, (b) Kidney of a G2 animal showing features of interstitial nephritis associated with glomerular sclerosis (arrowheads), tubular degeneration (tailed‐arrow), and interstitial inflammatory cell infiltration, mostly lymphocytes and macrophages (arrow), H&E, ×200, bar = 50 μm, (c) Kidney of a G3 animal showing marked decrease in lesions with still noticeable vacuolar tubular degeneration (arrow), H&E, ×200, bar = 50 μm, (d) Kidney of a G4 animal showing a moderate degree of tubular degeneration (arrows indicate vacuolation of tubular epithelium), H&E, ×200, bar = 50 μm, (e) Kidney of a G5 animal showing a marked decrease in tubular degeneration (arrow), H&E, ×200, bar = 50 μm.

FIGURE 4

Variation of the hepatic expression of caspase‐3 among the experimental groups. (a) Photomicrograph of a liver section from a rat of group (HFD) showing perivascular hepatic cells with intense positive cytoplasmic reactivity for caspase ‐3(peroxidase ×400), (b) Photomicrograph of a liver section from a rat of group (SIM) showing diffuse subcapsular hepatic cells with moderate positive cytoplasmic reactivity for caspase ‐3(peroxidase ×200), (c) Photomicrograph of a liver section from a rat of group (ZING) showing hepatic cells within hepatic parenchyma with weak positive cytoplasmic reactivity for caspase ‐3 ( peroxidase ×200), (d) Photomicrograph of a liver section from a rat of group (SIM+ZING) showing hepatic cells in the hepatic parenchyma with negative cytoplasmic reactivity for caspase ‐3 (peroxidase × 400).

FIGURE 5

The effect of ZING and SIM on the expression of HMG‐CoA reductase, iNOS, GLUT4, and PPAR‐γ genes in all experimental groups. The results were expressed as mean ± SD. Superscript stars indicate significant differences between test groups and the HFD control group, where (*) indicates p < .05 mildly significant, (**) p < .01 significant, (***) p < .001 highly significant, and NS, non‐significant.