Novel Curcumin Analogue L6H4 in Treating Liver Fibrosis and Type 2 Diabetes

Purpose

The objective of this study was to evaluate the therapeutic efficacy of the curcumin analogue L6H4 in attenuating liver fibrosis and alleviating insulin resistance in streptozotocin-induced diabetic rats.

Methods

Male Sprague-Dawley rats were fed a high-fat diet to induce insulin resistance, followed by streptozotocin injection to induce diabetes. The rats were then treated with L6H4 for eight weeks. Body weight, metabolic parameters, liver function, and liver histopathology were evaluated. Immunohistochemistry was performed to assess the expression of TGF-β1, TIMP-2, and MMP-2 in liver tissues. Statistical analysis was conducted using one-way ANOVA and Spearman rank correlation test.

Results

L6H4 treatment effectively reversed the weight gain associated with a high-fat diet and improved metabolic parameters in diabetic rats. Liver function markers, such as ALT and AST, were reduced after L6H4 treatment. Histological analysis showed improved liver morphology and reduced fibrosis in L6H4-treated rats. Electron microscopy revealed improved ultrastructural features of hepatocytes. Immunohistochemistry demonstrated downregulation of TGF-β1 and TIMP-2 expression and restoration of MMP-2 expression in the liver tissue of L6H4-treated rats. Correlation analysis showed a significant positive correlation between TGF-β1 and TIMP-2 expression.

Conclusion

The findings suggest that L6H4 has therapeutic potential in attenuating liver fibrosis and alleviating insulin resistance in streptozotocin-induced diabetic rats. The hepatoprotective effect of L6H4 may be attributed to its anti-inflammatory properties and its ability to target molecules involved in fibrosis. Further research is warranted to explore the potential of L6H4 as a treatment option for nonalcoholic fatty liver disease and type 2 diabetes.

Evaluation of the neuroprotective effect of donepezil in type 2 diabetic rats

Recent studies raise the possibility that donepezil can delay the progression of Alzheimer's disease (AD). This research evaluated the efficacy of donepezil in an animal model with brain insulin resistance and AD-like alterations. Rats were fed with high-fat/high-fructose (HF/Hfr) diet during the study period (17 weeks) and received one injection of streptozotocin (STZ) (25 mg/kg) after 8 weeks of starting the study. Diabetic (T2D) rats were treated with donepezil (4 mg/kg; p.o.) or vehicle for 8 weeks after STZ injection. The influence of donepezil on AD-related behavioral, biochemical, and neuropathological changes was investigated in T2D rats. Treatment of diabetic rats with donepezil led to a significant decrease in both amyloid-β deposition and the raised hippocampal activity of cholinesterase (ChE). It significantly increased the suppressed glutamate receptor expression (AMPA GluR1 subunit and NMDA receptor subunits NR1, NR2A, NR2B). It also improved cognitive dysfunction in the passive avoidance and the Morris water maze tests. However, donepezil treatment did not significantly decrease the elevated levels of P-tau, caspase-3, GSK-3β, MDA, TNF-α, and IL-1β in the hippocampus of diabetic rats. Also, it did not restore the suppressed levels of glutathione and superoxide dismutase in the brain of these rats. Moreover, donepezil did not alter the elevated serum level of glucose, insulin, and total cholesterol. These findings suggest that donepezil treatment could ameliorate learning and memory impairment in T2D rats through reversal of some of the AD-related alterations, including reduction of amyloid-β burden and ChE activity as well as restoration of glutamate receptor expression. However, lack of any significant effect on P-tau load, oxidative stress, neuroinflammation, and insulin resistance raises the question about the ability of donepezil to delay the development or arrest the progression of T2D-induced AD and it is still a matter of debate that requires further studies.

Effects and mechanism of stem cells from human exfoliated deciduous teeth combined with hyperbaric oxygen therapy in type 2 diabetic rats

OBJECTIVES

Mesenchymal stem cells (MSCs) are potentially ideal for type 2 diabetes treatment, owing to their multidirectional differentiation ability and immunomodulatory properties. Here we investigated whether the stem cells from human exfoliated deciduous teeth (SHED) in combination with hyperbaric oxygen (HBO) could treat type 2 diabetic rats, and explored the underlying mechanism.

METHODS

SD rats were used to generate a type 2 diabetes model, which received stem cell therapy, HBO therapy, or both together. Before and after treatment, body weight, blood glucose, and serum insulin, blood lipid, pro-inflammatory cytokines (tumor necrosis factor-alpha and interleukin-6), and urinary proteins were measured and compared. After 6 weeks, rats were sacrificed and their organs were subjected to hematoxylin and eosin staining and immunofluorescence staining for insulin and glucagon; apoptosis and proliferation were analyzed in islet cells. Structural changes in islets were observed under an electron microscope. Expression levels of Pdx1, Ngn3, and Pax4 mRNAs in the pancreas were assessed by real-time quantitative polymerase chain reaction (RT-qPCR).

RESULTS

In comparison with diabetic mice, those treated with the combination or SHE therapy showed decreased blood glucose, insulin resistance, serum lipids, and pro-inflammatory cytokines and increased body weight and serum insulin. The morphology and structure of pancreatic islets improved, as evident from an increase in insulin-positive cells and a decrease in glucagon-positive cells. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) staining of islet cells revealed the decreased apoptosis index, while Ki67 and proliferating cell nuclear antigen staining showed increased proliferation index. Pancreatic expression of Pdx1, Ngn3, and Pax4 was upregulated.

CONCLUSION

SHED combined with HBO therapy was effective for treating type 2 diabetic rats. The underlying mechanism may involve SHED-mediated increase in the proliferation and trans-differentiation of islet β-cells and decrease in pro-inflammatory cytokines and apoptosis of islets.

A novel berberine-metformin hybrid compound exerts therapeutic effects on obese type 2 diabetic rats

In this study, we investigated the biological activities of a novel berberine-metformin hybrid compound (BMH473) as an anti-diabetic agent. BMH473 exhibited significant anti-hyperglycaemic and anti-hyperlipidaemic effects on T2DM rats. In white adipose tissue, BMH473 reduced the perirenal and epididymal adipose tissue mass and modulated the lesions in perirenal adipose tissue, by inhibiting the protein expressions of PPAR-Ɣ, C/EBP-α and SREBP-1c as well as the mRNA expressions of lipogenic genes. Moreover, BMH473 downregulated the levels of pro-inflammatory cytokines in perirenal adipose tissue through the suppression of p-NF-κB. In liver, BMH473 reduced liver ectopic fat accumulation, by regulating the protein expression levels of SREBP-1c and PPAR-α as well as the mRNA expression levels of lipogenic genes. In addition, BMH473 inhibited hepatic gluconeogenesis by promoting the phosphorylation levels of AMPK α and ACC, and down-regulating the mRNA expression levels of FBPase, G6Pase and PEPCK. Furthermore, BMH473 exhibited significant inhibitory effects on lipogenesis and lipid accumulation in 3T3-L1 adipocytes by modulating the protein expression levels of PPAR-Ɣ, C/EBP-α and SREBP-1 c as well as the mRNA expression levels of lipogenic genes. In conclusion, our results suggest that the newly synthesized BMH473 is beneficial for maintaining glucose and lipid homeostasis in type 2 diabetic rats, and exhibits better anti-hyperlipidaemic effects compared to metformin and berberine.

Effects of Honokiol on CYP450 Activity and Transporter mRNA Expression in Type 2 Diabetic Rats

This study was aimed to clarify the effect of honokiol (Hon) on the activity of Cytochrome P450 (CYP450) enzymes, and the level of mRNA expression of liver and kidney transporters in type 2 diabetic rats induced by high-fat diet and strepotozotocin. Rats were randomly divided into normal control (NC) group, diabetic control (DC) group and Hon groups (n = 6). The activities of hepatic CYP1A2, CYP2E1, CYP2C, CYP2B, CYP3A and CYP4A, and the mRNA expression levels of hepatic and renal transporters, were determined. Compared to the NC group, the activities of CYP1A2, CYP2E1, CYP4A and CYP2C in DC group were increased by 2.36-, 2.10-, 2.55- and 1.86-fold, respectively. The mRNA expression levels of hepatic Oat2, Oatp2b1 and Oatp1a5, and renal Oct1, Octn2, Oatp2b1 and Oatp1a5, were significantly down-regulated, while the mRNA expression levels of hepatic Octn2, Oatp3a1, Oatp1a1 and Mdr2, and renal Oat2, Mrp4 and Bcrp, were significantly upregulated. Compared to the DC group, Hon treatment significantly inhibited the activity of hepatic CYP2E1, CYP4A, 3A and CYP1A2 by 45.6%, 29.2%, 22.7% and 20.7% in Hon high dose group, respectively. Moreover, Hon treatment significantly inhibited the mRNA expression levels of renal Bcrp and Mrp4 by 2.63-fold and 1.54-fold, while significantly upregulated the mRNA expression levels of hepatic Oat2 and Oatp2b1 by 1.52-fold and 1.54-fold in Hon high dose group, respectively. The results suggested that under the diabetes condition, the changes of CYP450 activity and transporter expression inevitably interfere the normal transport, metabolism and efficacy of drugs. The present work firstly reported that Hon treatment ameliorated the abnormal change of hepatic CYP activity (including CYP2E1, CYP4A and CYP1A2) and the transporter mRNA expression (including hepatic Oat2 and Oatp2b1, renal Bcrp and Mrp4) in type 2 diabetic rats induced by high-fat diet and strepotozotocin, which are associated with the occurrence and development of diabetes.

Urinary Kim-1 is a sensitive biomarker for the early stage of diabetic nephropathy in Otsuka Long-Evans Tokushima Fatty rats

Although urinary albumin is the well-known non-invasive marker for diabetic nephropathy, its sensitivity is relatively low. To select more adequate marker, we examined whether urinary tubular markers were more sensitive than albumin using spontaneous type 2 diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats. The OLETF rats exhibited histopathological alterations in glomeruli and tubules at 14 weeks of age, but there were no significant differences in the urinary albumin between OLETF and control, Long-Evans Tokushima Otsuka (LETO), rats at 10-16 weeks of age. In the OLETF rats, urinary excretions of N-acetyl-β-d-glucosaminidase and neutrophil gelatinase-associated lipocalin did not increase at least until 20 weeks of age, and urinary vanin-1 transiently increased at 18 weeks of age. On the other hand, urinary kidney injury molecule-1 (Kim-1) in the OLETF rats significantly increased at 14 weeks of age, and the elevation continued up to 22 weeks of age. In a clinical study, urinary KIM-1 levels tended to be higher in type 2 diabetic patients with and without albuminuria than in control subjects. These results suggest that compared to urinary albumin, urinary Kim-1 is a more sensitive biomarker for the detection of early stage of nephropathy in these type 2 diabetic animals. Merit of urinary KIM-1 in diabetic patients remains to be determined.