Ethanol extract of Liuwei Dihuang reduces weight gain and visceral fat in obese-prone CD rats fed a high-fat diet

Longevity Effect of Liuwei Dihuang in Both Caenorhabditis Elegans and Aged Mice

Liuwei Dihuang (LWDH), a famous traditional Chinese medicine, is widely used in the clinical treatment of aging-related diseases in China. However, its pharmacological mechanisms are not clear. In the present study, we evaluated the lifespan extension effect of LWDH in C. elegans and mice and revealed its underlying mechanisms. The results showed that LWDH significantly extended the lifespan of C. elegans in a dose-dependent manner. LWDH also conferred protection to nematodes against oxidative stress and reduced their fat storage. Genetics analysis and microarray data showed that the longevity effect of LWDH was attributed to the regulation of the innate immune response, proteolysis, lipid metabolism, and the oxidation-reduction process and was dependent on daf-16. Among the six herbs in the formula, Radix Rehmanniae Preparata and Fructus Macrocarpii contributed most to the longevity effect of this medicine, while the other four components had a synergistic effect on the longevity effect of the prescription. The lack of any single herb reduced the efficacy of the complete formula. LWDH also extended the lifespan and reduced both the weight and oxidant stress status in aged mice. Taken together, these results suggested that LWDH might function in a multi-target manner to extend the lifespan in both C. elegans and aged mice, and the best effect was achieved with the complete formula.

Inhibition of N-methyl-N-nitrosourea-induced gastric tumorigenesis by Liuwei Dihuang Pill in db/db mice

AIM

To investigate the inhibitory effect of Liuwei Dihuang Pill (LDP) on gastric tumorigenesis induced by N-methyl-N-nitrosourea (MNU) in diabetic mice.

METHODS

Four-week-old mice were divided into four groups: A, 12 db/m mice treated with MNU and saline, as the non-diabetic control; B, 12 db/db mice treated with MNU and saline, as the diabetic control; C, 12 db/db mice treated with MNU and metformin, as the positive control; and D, 12 db/db mice treated with MNU and LDP. MNU was administrated for 20 wk to induce gastric carcinogenesis. LDP was administrated for 10 wk for improvement of insulin resistance. Body weight and food intake were measured every week. Blood samples were collected for assays of fasting blood glucose, insulin, insulin-like growth factor (IGF)-1, adiponectin and leptin. Stomach tissues were collected for histopathological analysis, immunohistochemical staining of Ki67, quantitative reverse transcription-polymerase chain reaction and western blotting.

RESULTS

The incidence of MNU-induced gastric dysplasia was significantly elevated in diabetic (db/db) mice relative to the control (db/m) mice. The incidence of gastric dysplasia was significantly reduced by LDP with suppression of cell proliferation, as demonstrated by a decrease in Ki67 staining. Hyperglycemia, hyperinsulinemia and serum IGF-1 were inhibited by LDP. Expression of IGF-1 and insulin receptor mRNAs was decreased, phosphorylation of IGF-1 receptor and AKT protein was reduced in the stomach tissues by LDP. In addition, adiponectin was increased and leptin was decreased in the serum by LDP.

CONCLUSION

LDP decreased risk of gastric dysplasia in type 2 diabetic mice by down-regulation of IGF and insulin activity and correction of adipokines disorders.

The Korean herbal formulation Yukmijihwangtang stimulates longitudinal bone growth in animal models

Background

Yukmijihwangtang (YJT) is a traditional Korean medicine that has been used to treat kidney-yin deficiency symptoms such as dizziness and tinnitus. In addition, because it is also thought to nourish kidney-yin, it has been used to treat short stature from congenital deficiency. This study evaluated the effects of YJT on longitudinal bone growth in rats.

Methods

Female adolescent rats were randomly assigned to groups that received distilled water (per os [p.o.] twice a day; control), recombinant human growth hormone (rhGH; 20 μg/kg, subcutaneous [s.c.] once a day), or two different doses of YJT (100 or 300 mg/kg, p.o. twice a day). In each group, treatment was maintained for 4 days. Rats were injected intraperitoneally with 5-bromo-2’-deoxyuridine (BrdU; 50 mg/kg) to label proliferating chondrocytes on days 2 – 4. Tetracycline hydrochloride (20 mg/kg) was injected intraperitoneally to form fluorescent bands on the growth plates on day 3 for measuring the longitudinal bone growth rate. Expression of insulin-like growth factor-1 (IGF-1) and bone morphogenetic protein-2 (BMP-2) in the growth plate was identified using immunohistochemistry.

Results

There was a significant increase in the rate of bone growth in the 300 mg/kg YJT group (523.8 ± 23.7 μm/day; P < 0.05) compared to the control group (498.0 ± 23.8 μm/day), while the 100 mg/kg YJT group exhibited a non-significant increase. The number of BrdU-positive cells in the chondrocytes of the rhGH-treated group exhibited a significant increase (103.8 ± 34.2 cells/mm²) compared to that of the control group (70.3 ± 19.7 cells/mm²), while the 300 mg/kg YJT group had a non-significant increase. Additionally, IGF-1 and BMP-2 were highly expressed in the growth plate in the 300 mg/kg YJT and rhGH groups.

Conclusions

YJT increased the longitudinal bone growth rate by stimulating chondrocyte proliferation with increasing increments of local IGF-1 and BMP-2 expression. Based on these findings, YJT may be a therapeutic candidate for the treatment of growth retardation during adolescence.

Shrimp oil extracted from the shrimp processing waste reduces the development of insulin resistance and metabolic phenotypes in diet-induced obese rats

Diet-induced obesity, insulin resistance, impaired glucose tolerance, chronic inflammation, and oxidative stress represent the main features of type 2 diabetes mellitus. The present study was conducted to examine the efficacy and mechanisms of shrimp oil on glucose homeostasis in obese rats. Male CD rats fed a high-fat diet (52 kcal% fat) and 20% fructose drinking water were divided into 4 groups and treated with the dietary replacement of 0%, 10%, 15%, or 20% of lard with shrimp oil for 10 weeks. Age-matched rats fed a low-fat diet (10 kcal% fat) were used as the normal control. Rats on the high-fat diet showed impaired (p < 0.05) glucose tolerance and insulin resistance compared with rats fed the low-fat diet. Shrimp oil improved (p < 0.05) oral glucose tolerance, insulin response, and homeostatic model assessment-estimated insulin resistance index; decreased serum insulin, leptin, hemoglobin A1c, and free fatty acids; and increased adiponectin. Shrimp oil also increased (p < 0.05) antioxidant capacity and reduced oxidative stress and chronic inflammation. The results demonstrated that shrimp oil dose-dependently improved glycemic control in obese rats through multiple mechanisms.