2-dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione isolated from Averrhoa carambola L. root ameliorates diabetic nephropathy by inhibiting the TLR4/MyD88/NF-κB pathway

Abstract

Background

Averrhoa carambola L. is a traditional medicinal herb that has long been used to treat diabetes. Our previous studies found that 2-dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione (DMDD) isolated from A. carambola L. roots could ameliorate diabetic nephropathy (DN), but its exact mechanism remains unclear.

Methods

A DN model was established by streptozotocin (STZ, 100 mg/kg body weight) in TLR4 knockout (TLR4-/-, KO) mice and wild-type (WT) mice. Body weight and blood glucose were evaluated after oral administration of DMDD (12.5, 25, 50 mg/kg body weight/d) in diabetic mice. The levels of serum lipids, including TC, TG, HDL, and LDL and kidney function indexes Scr and BUN, were detected by biochemical equipment. The levels of inflammatory cytokines including IL-6 and TNF-α, were determined by ELISA kits. Furthermore, changes in renal ultrastructure were observed by electron microscopy. Western blot analysis and RT-PCR were used to assess the protein expression and mRNA levels of TLR4, MyD88 and NF-κB.

Results

DMDD treatment attenuated diabetic nephropathy, as a result of a decline in blood glucose, serum creatinine, and blood urine nitrogen levels and an increase in the quantity and density of podocytes, combined with improved dyslipidaemia. DMDD treatment inhibited the inflammatory response and downregulated the expression of the TLR4/MyD88/NF-κB pathway in diabetic mice, and these changes were significantly different in TLR4-/- mice.

Conclusion

DMDD alleviates diabetic nephropathy by mitigating kidney damage and inflammation via the inhibition of the TLR4/MyD88/NF-κB signalling pathway.

Keywords:

• 2-dodecyl-6-methoxycyclohexa-2,5-diene-1,4-dione
• diabetic nephropathy
• TLR4/MyD88/NF-κB signalling pathway

View correction statement:

2-Dodecyl-6-Methoxycyclohexa-2,5-Diene-1,4-Dione Isolated from Averrhoa carambola L. Root Ameliorates Diabetic Nephropathy by Inhibiting the TLR4/MyD88/NF-κB Pathway [Corrigendum]

Acknowledgments

This work was supported by the National Natural Science Foundation of China (No. 81760665, 81460205, 81360129), Innovation Project of Guangxi Graduate Education (YCBZ2018043, YCBZ2017043), and the Postdoctoral Science Foundation of China (No. 2017M613271XB).

Disclosure

The authors report no conflicts of interest in this work.