Effect of sleeve gastrectomy on renal oxidative stress in type 2 diabetic rats

Abstract

Objective To investigate the changes of oxidative stress in kidney of type 2 diabetic rats after sleeve gastrectomy and its effect on renal function. Methods Twenty male SD rats were fed with high-fat diet and injected with streptozotocin intraperitoneally to induce type 2 diabetes mellitus. Seventeen successful induction models were divided into sham operation group (n=7) and sleeve gastrectomy (SG) group (n=10) by random number table method, and were treated with sham operation and SG respectively. The body weight, 24-hour food intake, fasting blood glucose (FBG)and serum glucagon-like peptide-1 (GLP-1) were measured before and 1, 2, 3 and 4 weeks after operation. The activities of superoxide dismutase (SOD), catalase, glutathione peroxidase (GSH-Px) and malondialdehyde in renal tissue as well as blood urea nitrogen (BUN), creatinine levels and 24-hour urinary microalbumin (UALB) were measured 4 weeks after operation. Masurement data conforming to normal distribution were expressed as Mean±SD, and t-test was used for comparison between two groups. Results At the 1st, 2nd, 3rd, 4th weeks after operation, the levels of FBG in SG group was lower than those in sham operation group [(11.13±3.27) mmol/L vs (16.74±4.10) mmol/L, (9.53±2.82) mmol/L vs (19.31±3.66) mmol/L, (6.69±2.44) mmol/L vs (20.84±2.71) mmol/L, (6.58±2.96) mmol/L vs (19.99±2.85) mmol/L, all P<0.05]. In the same period, the levels of serum GLP-1 in SG group was higher than those in sham operation group [(22.61±2.92) pg/mL vs (15.42±2.39) pg/mL, (24.72±3.02) pg/mL vs (16.20±2.26) pg/mL, (24.59±2.85) pg/mL vs (15.84±2.75) pg/mL, (26.15±3.23) pg/mL vs (15.77±2.79) pg/mL, all P<0.05]. At the 4th week after operation, BUN[(5.34±0.82) mmol/L], creatinine[(39.78±6.13)]μmol/L, UALB[(31.18±6.88) mg/24 h] and renal creatinine[(5.84±0.85) nmol/mg] in SG group were lower than those in sham operation group [BUN (9.08±1.54) mmol/L, creatinine (64.07±8.63) μmol/L, UALB (67.64±9.07) mg/24 h, creatinine (10.78±1.28) nmol/mg], and the differences were statistically significant (all P<0.05). Renal SOD[(620.05±55.98) U/mg], CAT[(24.72±2.28) U/mg] and GSH-Px[(281.53±27.99) U] in SG Group were lower than those in sham operation group [SOD(392.52±45.97) U/mg, catalase (15.62±2.46) U/mg, GSH-Px (164.71±21.83) U], and the differences were statistically significant (all P<0.05). Conclusion Sleeve gastrectomy may improve renal function through reducing oxidative stress in the kidney. Key words: Diabetes mellitus, type 2; Diabetic nephropathies; Superoxides; Sleeve gastrectomy; Oxidative stress