XVABSTRACTTunçdemir M. The effects of ACE inhibitor and angiotensin receptor blocker onclusterin and apoptosis in the kidney tissue of streptozotocin-diabetic rats. İstanbulUniversity, Institute of Health Science, Medical Biology Dept. Ph.D.Thesis. Istanbul2006.The aim of this study was to determine the roles of secreted clusterin (s-clu) and nuclearclsuterin (n-clu) expressions in experimental diabetic nephropathy, and to investigatethe effects on clusterins expression after treatment angiotensin II blockade and comparethese results with apoptosis. Five groups, each containing 8 male Wistar albino ratswere included in this study. Four groups received streptozotocin injection (STZ, 60mg/kg, single dose, ip). On the 2nd day of STZ injection the rats developing diabeteswere divided into 4 groups. First group was STZ-diabetic. Second group was irbesartantreated diabetics (15 mg/kg/day, gavage, 30 days). Third group was perindopril treateddiabetics (6 mg/kg/day, gavage, 30 days), Fourth group was combined treated diabeticgroup with perindopril and irbesartan (respectively, 3 mg/kg/day, 5 mg/kg/day, gavage,30 days). Fifth group was the healthy control. During the experimental period bloodglucose, microalbuminuria levels, body weights, kidney weight and amount of dailyurine were measured. At the end of experiment, renal tissue samples were fixed informaline and embedded in paraffin. PAS staining and TUNEL method andimmunohistochemical staining for TGF-β1, α-SMA, clusterin-β (for s-clu) andclusterin-α/β (for n-clu) antigenes were performed for histological examinations. Bloodglucose levels and body weight/kidney weight values of all STZ-diabetic groups werehigher than the healthy control group. The level of daily urine and microalbuminurialevels were decreased in the all treated diabetic groups (p<0,001). As the number ofapoptotic cells increased especially in the kidney tubules of STZ-diabetic group(p<0,001), whereas a significant decrease was observed in the combined drug treatedgroup (p<0,05). When compared with the untreated diabetic group the expressions ofTGF-β1 and α-SMA were decreased in the all treated diabetic group. The expression ofclusterin-β was increased in the glomerules and tubules of the untreated diabetic group,although it was decreased in the treated diabetic groups. Immunopositivity ofclusterin-α/β in the podocytes and mesangial cells and in the injured tubule cells ofuntreated diabetic group was found to be increased in their nuclei. The number ofXVIimmunopositive cells was decreased in the treated diabetic groups, especially in thecombined treated diabetic group (p<0,05). It was concluded that, the increase in theexpression of TGF-β1 and α-SMA in glomeruli was a marker of renal injury, seen inthe early stages of diabetes as a result of damage caused by local increased expressionof RAS in the renal tissue induced by hyperglycemia. In the early stages of diabetes,the increase in the number of the apoptotic cells in the tubules, seen was one of thecauses of tubular damage. Our results also show that the expression of s-clu wasinduced in the experimental diabetic nephropathy related to renal tissue damage and thatthe increase in the n-clu expression in the renal tubules was releated to apoptosis.Although irbesartan (AT-1R blocker), perindopril (ACEI) and combined drug treatmentprevented renal injury in the diabetes, low dose application of ACEI and AT-1R blockertogether revealed more efficient results in preventing renal damages.Key Words: STZ-diabetes, Kidney, Clusterin, Apoptosis, TGF-βThis study was supported by The Research Support Unit of İstanbul University as theproject no: T-283/18062003.

XVABSTRACTTunçdemir M. The effects of ACE inhibitor and angiotensin receptor blocker onclusterin and apoptosis in the kidney tissue of streptozotocin-diabetic rats. İstanbulUniversity, Institute of Health Science, Medical Biology Dept. Ph.D.Thesis. Istanbul2006.The aim of this study was to determine the roles of secreted clusterin (s-clu) and nuclearclsuterin (n-clu) expressions in experimental diabetic nephropathy, and to investigatethe effects on clusterins expression after treatment angiotensin II blockade and comparethese results with apoptosis. Five groups, each containing 8 male Wistar albino ratswere included in this study. Four groups received streptozotocin injection (STZ, 60mg/kg, single dose, ip). On the 2nd day of STZ injection the rats developing diabeteswere divided into 4 groups. First group was STZ-diabetic. Second group was irbesartantreated diabetics (15 mg/kg/day, gavage, 30 days). Third group was perindopril treateddiabetics (6 mg/kg/day, gavage, 30 days), Fourth group was combined treated diabeticgroup with perindopril and irbesartan (respectively, 3 mg/kg/day, 5 mg/kg/day, gavage,30 days). Fifth group was the healthy control. During the experimental period bloodglucose, microalbuminuria levels, body weights, kidney weight and amount of dailyurine were measured. At the end of experiment, renal tissue samples were fixed informaline and embedded in paraffin. PAS staining and TUNEL method andimmunohistochemical staining for TGF-β1, α-SMA, clusterin-β (for s-clu) andclusterin-α/β (for n-clu) antigenes were performed for histological examinations. Bloodglucose levels and body weight/kidney weight values of all STZ-diabetic groups werehigher than the healthy control group. The level of daily urine and microalbuminurialevels were decreased in the all treated diabetic groups (p<0,001). As the number ofapoptotic cells increased especially in the kidney tubules of STZ-diabetic group(p<0,001), whereas a significant decrease was observed in the combined drug treatedgroup (p<0,05). When compared with the untreated diabetic group the expressions ofTGF-β1 and α-SMA were decreased in the all treated diabetic group. The expression ofclusterin-β was increased in the glomerules and tubules of the untreated diabetic group,although it was decreased in the treated diabetic groups. Immunopositivity ofclusterin-α/β in the podocytes and mesangial cells and in the injured tubule cells ofuntreated diabetic group was found to be increased in their nuclei. The number ofXVIimmunopositive cells was decreased in the treated diabetic groups, especially in thecombined treated diabetic group (p<0,05). It was concluded that, the increase in theexpression of TGF-β1 and α-SMA in glomeruli was a marker of renal injury, seen inthe early stages of diabetes as a result of damage caused by local increased expressionof RAS in the renal tissue induced by hyperglycemia. In the early stages of diabetes,the increase in the number of the apoptotic cells in the tubules, seen was one of thecauses of tubular damage. Our results also show that the expression of s-clu wasinduced in the experimental diabetic nephropathy related to renal tissue damage and thatthe increase in the n-clu expression in the renal tubules was releated to apoptosis.Although irbesartan (AT-1R blocker), perindopril (ACEI) and combined drug treatmentprevented renal injury in the diabetes, low dose application of ACEI and AT-1R blockertogether revealed more efficient results in preventing renal damages.Key Words: STZ-diabetes, Kidney, Clusterin, Apoptosis, TGF-βThis study was supported by The Research Support Unit of İstanbul University as theproject no: T-283/18062003.