The relationship between autophagy and renal tissue injury in adriamycin nephropathy rats / 中华肾脏病杂志

ABSTRACT

Objective To observe the formation of autophagosome,the expression and distribution of autophagy-related protein LC3-Ⅰ,LC3-Ⅱ and Beclin-1 in adriamycin nephropathy rats at different pathological periods,to explore the relationship between autophagy and renal tissue injury,the occurrence of proteinuria,the progression of renal disease.Methods Sixty normal male SD rats were randomly divided into control group (n=30) and model group (n=30),the rats in model group were injected with adriamycin(6.5 mg/kg) via tail-vein for one time,while the rats in control group were injected with saline.Urine protein quantitation of 24 hour,the levels of serum albumin and total cholesterol were measured serially at the 2,4,6,8,10 weeks.The changes of kidney tissue pathology were detected after HE,PAS and Masson staining by light microscope.The formation of autophagy were detected by transmission electron microscopy,the localization and distribution of LC3-Ⅰ,LC3-Ⅱ and Beclin-1 were detected by indirect immunofluorescence staining in kidney tissue,the autophagy-related proteins LC3-Ⅰ,LC3-Ⅱ and Beclin-1 expression was detected by Western blotting.Results In model group,urinary protein began to increase at the first two weeks,serum albumin decreased at the same time,and total cholesterol increased in the four weeks.There was a statistically significant difference compared with the control group (P ＜ 0.01).The Scr and BUN were increased slightly at the four weeks in model group,and showed the deterioration of renal function after the eight weeks.There was a statistically significant difference compared with the control group (P ＜ 0.01).Mesangial cell proliferation,mitochondrial swelling and foot process broadening and integration appeared early in the model group,while foot process disappearing and nuclear pyknosis were observed in the late by transmission electron microscope;Renal pathology gradually changed from mesangial proliferation to focal segmental glomerulosclerosis (FSGS) by light microscope.A low expression of autophagy was detected in renal tissue of control group rats by transmission electron microscopy and immunofluorescence microscope;in model group,with the progression of disease,the autophagy was significantly enhanced and maintained at a high level.With the progression of disease,the autophagyrelated proteins LC3-Ⅰ,LC3-Ⅱ and Beclin-1 was significantly enhanced in the model group than the control group (P＜0.05).Conclusion Autophagy is involved in renal tissue injury and the occurrence of proteinuria,closely related to the progression of renal disease.