Investigation On Renal Protective Effect Of Leech Earth-Worm Injection In Diabetic Rats

Objective To investigate the protective effect and possible mechanisms of leech earth-worm injection in rats with diabetic mellitus(DM).Methods Diabetic nephropathy(DN) model of rats was induced by intraperitoneal injection of streptozotocin(STZ).The rats were randomly divided into 4 groups: normal control group(N group), DN group without any treatment(A group), DN group treated with leech earth-worm injection(B group) and DN group treated with benazepril(C group).Then leech earth-worm injection following intraperitoneal injection(1ml/kg per day) began to be gived to the B group rats, and benazepril(10mg/kg per day) was gived to the C group rats.Before the induction of DN and four,eight weeks later, the urinary albumin(uAlb), urinaryβ2-microglobulin(β2-MG) and Urinary creatinine(Ucr) were measured, using the ratio of urinary albumin/creatinne(Alb/Ucr) to express urinary albumin excretion.Fasting body weight and fasting blood glucose were measured before the induction of DN and eight weeks later.At the end of eight weeks after the indunction of DN,the left kidney weight, serum creatinine(Scr) and blood urea nitrogen(BUN) were measured, creatinine clearance rate (Ccr) and kidney hypertrophy index(KI, expressed by the ratio of left kidney weight/body weight) were calculated.The kidney sections were stained with Van Gieson(VG) and periodic acid Schiff (PAS) and The pathological changes of kidney were observed with microscope.The expression of transforming growth factor-beta1(TGF-β1) and type IV collagen (CIV) in kidney were examined using immunohistochemical assay.Results (1)Compared with N group rats, A group rats had a decrease of body weight and had an increase of fasting blood glucose, Alb/Ucr, urinaryβ2-MG, KI, Scr, BUN and Ccr (P<0.05 or P<0.01);Compared with A group, B group and C group rats had no significant difference in fasting blood glucose (P>0.05) , had an increase of body weight (P<0.01) and had a decrease of Alb/Ucr, urinaryβ2-MG, KI, Scr, BUN and Ccr (P<0.05 or P< 0.01);Compared with C group, B group had a decreased of Alb/Ucr (P<0.05) and had no significant difference in body weight, fasting blood glucose, urinaryβ2-MG, KI, Scr, BUN and Ccr(P>0.05).(2)The results of kidney sections VG and PAS stain with microscope: In A group rats,significantly abnormal pathological changes in kidney were found.While in B and C group rats, the abnormal changes were all significantly improved.(3)The immunohistochemical semi-quantitative results of TGF-β1, CIV: Compared with N group, the expression of TGF-β1, CIV was significantly inhanced in A group(P<0.01); Compared with A group, B and C group had a decrease of the expression of TGF-β1, CIV in kidney (P<0.05), and there was no significant difference between this two groups(P>0.05).Conclusion (1) Leech earth-worm injection could improve the general state of experimental DN rats.(2) Leech earth-worm injection could decrease urinary albumin, urinaryβ2-MG, KI and Ccr in DN rats,so it has some protecting effect on diabetic kidney.(3) Leech earth-worm injection could improve the pathological changes of DN rats in kidney,it probably inhibit the expression of TGF-β1 and decrease the synthesis of CIV.