ABSTRACT
Objective To investigate the effect and potential mechanism of autophagy inhibitor chloroquine on the calcium oxalate crystals formation in rats.Methods From September 2016 to October 2016,Thirty healthy male SD rats were randomly divided into 3 groups:control group,model group and chloroquine intervention group.The method to establish calcium oxalate stone model was drinking water with 1％ ethylene and 1％ ammonium chloride freely.The rats of chloroquine intervention group were treat with chloroquine (40mg/kg · d) by intraperitoneal injection.Modeling was finished after 28 days.The amounts of renalcalcium oxalate crystals were detected by polarizing microscope.For all groups,the amounts of autophagosome were detected by transmission electron microscope.Twenty four hour urine compositions for stone risk factors were detected.The expressions of oxidative stress injury related molecular markers (SOD,MCP-1 and 8-OHdG) and the expressions of autophagy markers (LC3 and P62) were detected by immunohistochemistry.The RNA expressions of SLC26A6 in kidney were detected by Real-time PCR.Results Compared to the model group,the amounts of renal calcium oxalate crystals were significantly reduced in chloroquine intervention group (32.37 ± 5.14 vs.4.18 ± 0.25,P ＜ 0.05).Compared to the control group,the level of autophagy was increased in the model group.Compared to the model group,the level of autophagy was inhibited in the chloroquine intervention group.For control group,model group and chloroquine intervention group,the excretion of urinary oxalate were (3.1 ± 1.5) mmol,(22.5 ± 8.1) mmol,(2.8 ± 1.2) mmol,respectively;the excretion of urinary citrate were (63.4 ± 7.4) mmol,(45.9 ± 9.5)mmol,(15.6 ± 8.2) mmol,respectively.Compared to the control group,the amounts of urinary oxalate weresignificantly elevated in model group (P ＜ 0.05),but citrate were significantly reduced in the chloroquineintervention group(P ＜ 0.05).For control group,model group and chloroquine intervention group,theexpressions of SOD were 42.24 ±4.16,19.21 ± 2.25,39.08 3.53,respectively;the expressions of MCP-1 were 4.02 0.51,8.45 ± 0.55,5.52 ± 0.34,respectively;the expressions of 8-OHdG were 7.16 ± 0.54,11.21 ± 1.12,8.67 ±0.34,respectively;the RNA expressions of SLC26A6 were 0.35 ±0.07,1.02 ±0.17,0.70 ± 0.06,respectively.Compared to the control group,the expressions of SOD were significantly reduced in the model group,but the expressions of MCP-1,8-OHdG and SLC26A6 were significantly elevated(P ＜0.05).Compared to the model group,the expressions of SOD were significantly elevated chloroquine intervention group (P ＜ 0.05),but the expressions of MCP-1,8-OHdG and SLC26A6 were significantly elevated(P ＜ 0.05).Conclusions The autophagy inhibitor chloroquine could inhibit the formation of calcium oxalate crystals induced by ethylene in rat kidney via inhibit the renal autophagy level and expressions of the SLC26A6,reducing the renal oxidative stress injury and urinary oxalate excretion.