To investigate whether the supplemented Buyang Huanwu tang can improve the kidney injury in diabetic kidney disease (DKD) mice through regulating mitochondrial dynamics.

The db/db mice were randomized into the model group (0.2 mL·d^-1 distilled water), low and high-dose experimental groups (16.0, 32.0 g·kg^-1 supplemented Buyang Huanwu tang), with 8 mice in each group. Another 8 db/m mice were included in the normal group (0.2mL·d^-1 distilled water). The four groups were orally administered once a day for 8 consecutive weeks. Then, the levels of fasting blood glucose (FBG), total cholesterol (TC), triglyceride (TG), blood urea nitrogen (BUN), serum creatinine (SCr), and urinary microalbumin (mALB) were detected at the end of the experiment. The expression of mitofusin 1 (Mfnl), mitofusin 2 (Mfn2), optic atrophy 1 (Opa1), dynamin-related protein 1 (Drp1), fission protein 1 (Fis1), sirtuin 3 (SIRT3), transforming growth factor-β₁ (TGF-β₁), α-smooth muscle actin (α-SMA), collagen type Ⅲ (Col-Ⅲ) and fibronectin (FN) was measured by Western blotting.

The levels of TG in the experimental-L, -H groups, model group and normal group were (1.98±0.13), (1.69±0.13), (3.38±0.59) and (1.25±0.16) mmol·L^-1; the levels of TC were (3.86±0.14), (3.19±0.15), (5.41±0.61) and (1.46±0.19) mmol·L^-1; the levels of BUN were (10.04±2.21), (8.79±1.75), (16.92±4.57) and (4.78±1.07) mmol·L^-1; the levels of SCr were (19.17±2.25), (17.16±2.03), (27.92±4.13) and (13.37±1.77) μmol·L^-1; the levels of mALB were (26.92±4.61), (20.54±2.31), (46.78±7.32) and (6.14±1.13) mg·L^-1; the relative expression levels of TGF-β1 were 0.73±0.09, 0.59±0.05, 1.01±0.14 and 0.48±0.05; the relative expression levels of α-SMA were 0.79±0.09, 0.56±0.05, 1.12±0.11 and 0.55±0.04; the relative expression levels of FN were 0.61±0.03, 0.55±0.05, 0.83±0.09 and 0.22±0.03; the relative expression levels of Col-Ⅲ were 0.53±0.06, 0.35±0.05, 0.73±0.09 and 0.17±0.03; the relative expression levels of SIRT3 were 0.65±0.07, 0.41±0.14, 0.23±0.12 and 0.91±0.04; the relative expression levels of Drp1 were 0.54±0.08, 0.49±0.09, 0.98±0.11 and 0.37±0.03; the relative expression levels of Fis1 were 0.71±0.05, 0.51±0.03, 1.14±0.11 and 0.35±0.05; the relative expression levels of Mfn1 were 0.61±0.04, 0.95±0.05, 0.43±0.05 and 1.02±0.07; the relative expression levels of Mfn2 was 0.67±0.06, 0.89±0.09, 0.52±0.03 and 1.08±0.05; the relative expression levels of OPA1 were 0.77±0.06, 0.79±0.09, 0.52±0.03 and 1.13±0.11, respectively. Significant differences were found between the model group and experimental-L, -H groups (P<0.05, P<0.01). Simultaneously, the renal pathological and mitochondrial damage was significantly improved.

The supplemented Buyang Huanwu tang can maintain the balance of mitochondrial dynamics, thereby reducing urinary protein, alleviating renal injury and fibrosis. Its potential mechanism may be related to the regulation of SIRT3 protein expression.