OBJECTIVE To investigate possible protective effect of berberine,an isoquinoline alkaloid,is the major active constituent of Rhizoma coptidis and Cortex phellodendri,on high-fat diet/streptozotocin-induced early diabe...OBJECTIVE To investigate possible protective effect of berberine,an isoquinoline alkaloid,is the major active constituent of Rhizoma coptidis and Cortex phellodendri,on high-fat diet/streptozotocin-induced early diabetic nephropathy in rats and various mechanisms underlie this effect.METHODS The diabetic rat model was generated by a single intraperitoneal injection of streptozotocin(STZ,50 mg·kg-1).Diabetic rats were randomlyassigned into the following five groups:control,DN,losartan(30 mg·kg-1·d-1),berberine(100,200 mg·kg-1·d-1).Berberine and losartan were given intragastricly for nine weeks.At the end of the experiment,urine of each group was collected in a 24 h period.Rats were weighed and then sacrificed.Plasma and kidneys were collected.The levels of blood glucose,creatinine(Cr),triglycerides(TG),total cholesterol(TCH)and malondialdehyde(MDA)in serum were determined using commercial kits according to the manufacturer′s instructions.Transforming growth factor(TGF)-β1and intracellular adhesion molecule-1(IAM-1)mR NA levels were evaluated by RT-PCR.The renal histopathology was observed by light microscopy.Further biochemical analysis of IKKβ1 and p65(nucleus/cytoplasm)was provided using Western blotting techniques.RESULTS Our study has demonstrated that berberine has various pharmacological activities.The DN rats had significantly higher kidney/body weight ratio(17.4±1.4)mg·g-1,and berberine treatment could reduce this ratio change 13.6±0.6 and(11.6±0.8)mg·g-1,respectively;glucose control still remains the only disease-modifying therapy for diabetic complications,FBG was also recorded in the experiment.The findings reveal that the DN group showed a significantly higher glucose level(28.67±2.78)mmol·L-1.Treatment with8 weeks of berberine improved these parameters except blood glucose〔(18.67±2.59)mmol·L-1and 16.45±1.80 vs(28.67±2.78)mmol·L-1:plasma levels of urea nitrogen(15.67±2.48)mmol·L-1and 14.45±2.40 vs(12.26±2.40)mmol·L-1〕;plasma levels of 24 h urine albuminuria〔30.48±1.56 and 25.72±2.24 vs(15.26±0.12)μg·d-1〕;based on these results,berberine supposed to improve renal functions in diabetic rats.Berberine also ameliorated the inflammatory changes of DN in diabetic animals;levels of TG,TCH and MDA in berberine-treatment rats were significantly lower compared with those in the DN group:TG〔2.78±0.24 and 2.45±0.36 vs(5.20±0.60)mmol·L-1〕;TCH〔4.26±0.46 and 3.74±0.68 vs(6.26±0.50)mmol·L-1〕;MDA〔4.94±1.19 and 4.28±0.64 vs(4.28±0.64)nu·mL-1〕.Chronic inflammation,as is observed in diabetes,is associated with increased production of TGF-β1and IAM-1.Compared with the renal tissues of DN group,TGF-β1and IAM-1 gene expressions in berberine treated groups were reduced at the dose levels(100 and 200 mg·kg-1).And TGF-β1and IAM-1levels in berberine treated groups were reduced in a dosedependent manner:Relative expression of TGF-β1mR NA level(3.56±0.28 and 3.12±0.14 vs 5.12±0.44);Relative expression of IAM-1 mR NA leve(l1.78±0.56 and 1.42±0.24vs 4.36±0.35).Research finds that the NF-κB signaling pathway is activated in the renal tissue of diabetic mice and berberine inhibits activation of the NF-κB pathway:staining score for IKKβ1(4.34±0.26 and 3.82±0.24 vs 6.23±0.76),staining score for p65(2.34±0.26 and 1.74±0.78 vs 6.23±0.24)in nucleus and staining score for p65(7.21±0.13 and8.15±0.45 vs 4.23±0.54)in cytoplasm.CONCLUSION In this field,berberine suppresses the increased expression of p65 in the nucleus and decreases it in cytoplasm,which leads to the inhibition of the NF-κB pathway.These changes will result in decreasing the transcription and translation of many inflammatory mediators,such as TGF-β1and IAM-1.Additionally,these changes decrease the number of inflammatory cells and mononuclear macrophage infiltration into glomeruli and renal interstitium.These results indicated that berberine can protect the kidney of STZ-diabetic rats by reducing the expression of TGF-β1and IAM-1 in the renal tubulointerstitium.And we propose that berberinemayfunction as an effective therapeutic agent for diabetic nephropathy and attenuate the progression of renal injury.展开更多
基金The project supported by Fundamental Research Funds for the Central Universities(21615463)
文摘OBJECTIVE To investigate possible protective effect of berberine,an isoquinoline alkaloid,is the major active constituent of Rhizoma coptidis and Cortex phellodendri,on high-fat diet/streptozotocin-induced early diabetic nephropathy in rats and various mechanisms underlie this effect.METHODS The diabetic rat model was generated by a single intraperitoneal injection of streptozotocin(STZ,50 mg·kg-1).Diabetic rats were randomlyassigned into the following five groups:control,DN,losartan(30 mg·kg-1·d-1),berberine(100,200 mg·kg-1·d-1).Berberine and losartan were given intragastricly for nine weeks.At the end of the experiment,urine of each group was collected in a 24 h period.Rats were weighed and then sacrificed.Plasma and kidneys were collected.The levels of blood glucose,creatinine(Cr),triglycerides(TG),total cholesterol(TCH)and malondialdehyde(MDA)in serum were determined using commercial kits according to the manufacturer′s instructions.Transforming growth factor(TGF)-β1and intracellular adhesion molecule-1(IAM-1)mR NA levels were evaluated by RT-PCR.The renal histopathology was observed by light microscopy.Further biochemical analysis of IKKβ1 and p65(nucleus/cytoplasm)was provided using Western blotting techniques.RESULTS Our study has demonstrated that berberine has various pharmacological activities.The DN rats had significantly higher kidney/body weight ratio(17.4±1.4)mg·g-1,and berberine treatment could reduce this ratio change 13.6±0.6 and(11.6±0.8)mg·g-1,respectively;glucose control still remains the only disease-modifying therapy for diabetic complications,FBG was also recorded in the experiment.The findings reveal that the DN group showed a significantly higher glucose level(28.67±2.78)mmol·L-1.Treatment with8 weeks of berberine improved these parameters except blood glucose〔(18.67±2.59)mmol·L-1and 16.45±1.80 vs(28.67±2.78)mmol·L-1:plasma levels of urea nitrogen(15.67±2.48)mmol·L-1and 14.45±2.40 vs(12.26±2.40)mmol·L-1〕;plasma levels of 24 h urine albuminuria〔30.48±1.56 and 25.72±2.24 vs(15.26±0.12)μg·d-1〕;based on these results,berberine supposed to improve renal functions in diabetic rats.Berberine also ameliorated the inflammatory changes of DN in diabetic animals;levels of TG,TCH and MDA in berberine-treatment rats were significantly lower compared with those in the DN group:TG〔2.78±0.24 and 2.45±0.36 vs(5.20±0.60)mmol·L-1〕;TCH〔4.26±0.46 and 3.74±0.68 vs(6.26±0.50)mmol·L-1〕;MDA〔4.94±1.19 and 4.28±0.64 vs(4.28±0.64)nu·mL-1〕.Chronic inflammation,as is observed in diabetes,is associated with increased production of TGF-β1and IAM-1.Compared with the renal tissues of DN group,TGF-β1and IAM-1 gene expressions in berberine treated groups were reduced at the dose levels(100 and 200 mg·kg-1).And TGF-β1and IAM-1levels in berberine treated groups were reduced in a dosedependent manner:Relative expression of TGF-β1mR NA level(3.56±0.28 and 3.12±0.14 vs 5.12±0.44);Relative expression of IAM-1 mR NA leve(l1.78±0.56 and 1.42±0.24vs 4.36±0.35).Research finds that the NF-κB signaling pathway is activated in the renal tissue of diabetic mice and berberine inhibits activation of the NF-κB pathway:staining score for IKKβ1(4.34±0.26 and 3.82±0.24 vs 6.23±0.76),staining score for p65(2.34±0.26 and 1.74±0.78 vs 6.23±0.24)in nucleus and staining score for p65(7.21±0.13 and8.15±0.45 vs 4.23±0.54)in cytoplasm.CONCLUSION In this field,berberine suppresses the increased expression of p65 in the nucleus and decreases it in cytoplasm,which leads to the inhibition of the NF-κB pathway.These changes will result in decreasing the transcription and translation of many inflammatory mediators,such as TGF-β1and IAM-1.Additionally,these changes decrease the number of inflammatory cells and mononuclear macrophage infiltration into glomeruli and renal interstitium.These results indicated that berberine can protect the kidney of STZ-diabetic rats by reducing the expression of TGF-β1and IAM-1 in the renal tubulointerstitium.And we propose that berberinemayfunction as an effective therapeutic agent for diabetic nephropathy and attenuate the progression of renal injury.
