Abstract: Objective: To discuss the protective effects of extract from fermented buckwheat flower and leaf (EFBFL) on the kidney injury in the spontaneously obese type Ⅱ diabetic db/db mice,and to elucidate their possible action mechanisms from the protein expression levels of peroxisome proliferator-activated receptor γ(PPARγ) and nuclear factor-κB (NF-κB) in kidney tissue. Methods: The 8weeks old male db/db mice were selected and the littermate db/m mice were used as normal control group;the db/db mice were randomly divided into model group,low dose of EFBFL group and high dose of EFBFL group,10 mice in each group.The mice in low and high doses of EFBFL groups were intragastrically given 50 and 100 mg·kg^-1 EFBFL,and the mice in normal control group and model group were intragastrically given the equal amount of distilled water once daily for 8 weeks accordingly.The levels of fasting blood-glucose (FBG) of the mice in various groups were tested respectively before and after administration.Full automatic biochemical analyzer was used to detect the levels of serum creatinine (SCr) and blood urea nitrogen (BUN) of the mice,and the kidney index was calculated.The morphology of kidney tissue was observed by HE staining and Masson staining,and immunohistochemical method and Western blotting method were used to detect the expression levels of PPARγ and NF-κB protein in kidney tissue. Results: Compared with model group,the levels of FBG and the levels of serum SCr and BUN in EFBFL groups were significantly decreased(P<0.05 or P<0.01),and the kidney indexes were increased(P<0.01).Compared with normal control group,the kidney glomerular of the mice in model group was weaked,glomerular basement membrane was diffusely thickened,the foot process was coalesced or disappeared,and the kidney tissue fibrosis was serious; compared with the model group,the above performance of the mice in EFBFL groups were improved in different degrees,especially in high dose of EFBFL group. Compared with model group,the expression levels of PPARγ in kidney tissue of the mice in EFBFL groups were increased(P<0.01) and the expression levels of NF-κB in kidney tissue of the mice were decreased(P<0.01). Conclusion: EFBFL can improve the kidney injury in the spontaneously obese type Ⅱ diabetic db/db mice,and its possible mechanism may be related to lowering the level of blood glucose,up-regulating the expression of PPARγ and down-regulating the expression of NF-κB in the kidney tissue of the mice.

Key words: kidney injury, peroxisome proliferator-activated receptor γ, nuclear factor-κB, type 2 diabetes mellitus, db/db mice, extract from fermented buckwheat flower and leaf