Unraveling the Potential Role of Tecomella undulata in Experimental NASH

Abstract

The pathophysiology of nonalcoholic steatohepatitis (NASH) is complex, owing to its diverse pathological drivers and, until recently, there were no approved drugs for this disease. Tecomella is a popular herbal medicine used to treat hepatosplenomegaly, hepatitis, and obesity. However, the potential role of Tecomella undulata in NASH has not yet been scientifically investigated. The administration of Tecomella undulata via oral gavage lowered body weight, insulin resistance, alanine transaminase (ALT), aspartate transaminase (AST), triglycerides, and total cholesterol in western diet sugar water (WDSW) fed mice but had no effect on chow diet normal water (CDNW) fed mice. Tecomella undulata improved steatosis, lobular inflammation, and hepatocyte ballooning and resolved NASH in WDSW mice. Furthermore, Tecomella undulata also alleviated the WDSW-induced Endoplasmic Reticulum stress and oxidative stress, enhanced antioxidant status, and thus reduced inflammation in the treated mice. Of note, these effects were comparable to saroglitazar, the approved drug used to treat human NASH and the positive control used in the study. Thus, our findings indicate the potential of Tecomella undulata to ameliorate WDSW-induced steatohepatitis, and these preclinical data provide a strong rationale for assessing Tecomella undulata for the treatment of NASH.

Keywords: ER stress; hepatic inflammation; herbal medicine; insulin resistance; oxidative stress.

Figure 1

Tecomella undulata (TU) reduced body weight and improved insulin resistance in high fat diet-induced obese mice. Mice were treated with CDNW or WDSW for 12 weeks and, following that, WDSW mice were divided into 3 groups and treated with (i) vehicle control (VC) (ii) saroglitazar (SARO) (iii) Tecomella undulata (TU) via oral gavage for additional 12 weeks. At the completion of the treatment, body weight (A), liver weight (B), fasting glucose (C), and fasting insulin (D) were measured. HOMA-IR (E) was calculated using the formula: (fasting insulin (milliunits/liter) × fasting glucose (mmol/liter))/22.5. Data are expressed as mean with SEM for 8–10 mice per group. ## p < 0.001 compared to CDNW; ** p < 0.001 compared to WDSW, vehicle control.

Figure 2

Tecomella undulata (TU) improves glucose tolerance and insulin sensitivity. CDNW and WDSW mice treated with vehicle control (VC), saroglitazar (SARO) or Tecomella undulata (TU) for 12 weeks. Mice were fasted overnight and blood glucose concentration (mg/dl) was measured after intraperitoneal injection of 1 g/kg glucose (A). Mice fasted for 4–5 h were administered 0.75 units/kg insulin and blood glucose concentration (mg/dL) measured (B). The bar graphs depict the area under the curve (AUC) with or without treatment. Data are expressed as mean with SEM for 8–10 mice per group. ## p < 0.001 compared to CDNW; ** p < 0.001 or * p < 0.05 compared to WDSW, vehicle control.

Figure 3

Tecomella undulata (TU) treatment reduced liver injury and hyperlipidemia. CDNW or WDSW mice, after 12 weeks, were administered vehicle control (VC), saroglitazar (SARO) or Tecomella undulata (TU) for another 12 weeks. At the end of 24 weeks following dietary intervention and treatment, mice were fasted overnight and blood was collected. (A) serum ALT, (B) serum ALT, (C) serum triglycerides, (D) serum cholesterol (E) serum LDL-C. Data are expressed as the mean with SEM for 8–10 mice per group. ## p < 0.001 compared to CDNW; ** p < 0.001 or * p < 0.05 compared to WDSW, vehicle control. AST, aspartate aminotransferase; ALT, alanine aminotransferase; LDL-C, low-density lipoprotein-cholesterol.

Figure 4

Histological features of mice treated with Tecomella undulata (TU). Representative microscopic views of liver sections from CDNW or WDSW mice treated with vehicle control (VC), saroglitazar (SARO) or Tecomella undulata (TU). Intracellular lipid accumulation was determined by staining with (A) hematoxylin and eosin (H&E), and (B) Oil Red O.

Figure 5

Tecomella undulata (TU) treatment ameliorates fatty liver and steatohepatitis. CDNW or WDSW mice treated with vehicle control (VC), saroglitazar (SARO) or Tecomella undulata (TU) for 12 weeks. (A) hematoxylin and eosin (H&E) stained liver sections depicting steatosis, hepatocyte ballooning, and lobular inflammation. Histology score for (B) steatosis, (C) hepatocyte ballooning, (D) lobular inflammation, (E) NAFLD activity score were quantified. Data are expressed as the mean with SEM for 8–10 mice per group. ## p < 0.001 compared to CDNW; ** p < 0.001 or * p < 0.05 compared to WDSW, vehicle control.

Figure 6

Effect of Tecomella undulata (TU) on ER stress and oxidative stress in NASH mice. The relative expression of hepatic mRNA levels of CHOP (A), Grp78 (B), SOD (E), and CAT (F) were determined using qRT-PCR. The experiments were carried out in triplicate and β-actin was used as an endogenous control for normalizing the mRNA levels. Intracellular ROS production (C) and lipid peroxidation (MDA levels) (D) were determined in the liver tissues of CDNW and WDSW mice treated with vehicle control (VC), saroglitazar (SARO) or Tecomella undulata (TU). Data are expressed as the mean with SEM for 8–10 mice per group. ## p < 0.001 or # p < 0.05 compared to CDNW; ** p < 0.001 or * p < 0.05 compared to WDSW, vehicle control. CHOP, C/EBP homologous protein; Grp78, 78 kDa glucose regulated protein; SOD, superoxide dismutase; CAT, catalase; ROS, reactive oxygen species; MDA, malondialdehyde.

Figure 7

Tecomella undulata (TU) treatment ameliorated hepatic inflammation in NASH mice. The relative expression of hepatic mRNA levels of TNFα (A), and IL-1β (B) were determined using qRT-PCR. The experiments were carried out in triplicate and β-actin was used as an endogenous control for normalizing the mRNA levels. Whole cell lysates were prepared from liver tissue of CDNW and WDSW treated with vehicle control (VC), saroglitazar (SARO) or Tecomella undulata (TU) for 12 weeks. Immunoblot analyses were performed for p-Erk1/2 and Erk1/2 (C), and p-JNK and JNK (D). Bar graphs show the densitometric values calculated after normalization to total Erk1/2 or total JNK. Data are expressed as the mean with SEM. ## p < 0.001 compared to CDNW; ** p < 0.001, * p < 0.05 compared to WDSW, vehicle control. TNFα, tumor necrosis factor α; IL-1β, interleukin- 1β; p-Erk1/2, phospho-extracellular signal-regulated protein kinase; p-JNK, phosphor- c-Jun N-terminal kinase.

Figure 8

Schematic representation depicting the mechanisms involved in Tecomella undulata (TU)-mediated amelioration of NASH. Mice fed on WDSW for 12 weeks were treated with Tecomella undulata via oral gavage for another 12 weeks. Administration of Tecomella undulata ameliorated steatohepatitis in WDSW mice by improving insulin sensitivity, ER stress, oxidative stress, and increased production of antioxidants providing evidence that Tecomella undulata may have the potential to be used in the treatment of NASH.