C5b-9 does not mediate tubulointerstitial injury in experimental acute glomerular disease characterized by selective proteinuria

Table 1 Biochemical data in the experimental groups

Group	n	Serum protein (g/dL)	Serum albumin (g/dL)	Proteinuria (mg/24 h)	Serum creatinine (mmol/L)	Serum urea (mmol/L)
Control	9	65 ± 1	39 ± 1	2 ± 1	43 ± 3	7 ± 0
		(65, 63-66)	(39, 37-42)	(2, 1-2)	(40, 36-48)	(7, 6-8)
PON d 2 C6+	6	98 ± 31	74 ± 11	857 ± 1761	97 ± 171	27 ± 51
		(97, 92-102)	(74, 73-76)	(972, 679-1080)	(86, 67-117)	(23, 17-38)
PON d 2 C6-	5	97 ± 51	74 ± 41	789 ± 2141	117 ± 311	35 ± 111
		(99, 93-104)	(76, 71-79)	(788, 11-1145)	(97, 64-177)	(21, 17-58)
PON d 4 C6+	6	101 ± 21	73 ± 11	1214 ± 1311	93 ± 91	24 ± 21
		(102, 97-109)	(75, 72-76)	(1094, 1013-1197)	(94, 80-125)	(25, 20-30)
PON d 4 C6-	6	96 ± 21	70 ± 11	1026 ± 2671	76 ± 51	19 ± 11
		(95, 89-98)	(69, 67-73)	(965, 724-1719)	(73, 65-85)	(18, 17-21)
PON d 8 C6+	8	97 ± 31	68 ± 31	1177 ± 701	74 ± 61	24 ± 31
		(97, 88-101)	(70, 64-72)	(1165, 709-1321)	(65, 53-81)	(20, 15-29)
PON d 8 C6-	9	97 ± 21	70 ± 31	1227 ± 1161	69 ± 61	22 ± 31
		(99, 95-101)	(71, 70-73)	(1228, 952-1529)	(73, 52-86)	(19, 17-28)

Data are expressed as mean ± SEM (median, Inter-quartile range);

¹P < 0.05 compared to control group. PON: Protein-overload nephropathy.

Table 2 Body and kidney weight in the experimental groups

Group	n	Day 1 BW (g)	Final BW (g)	KW (g)	KW:BW
Control	9	186 ± 21	182 ± 5	0.60 ± 0.02	0.33 ± 0.01
		(196, 158-200)	(192, 168-195)	(0.62, 0.53-0.66)	(0.33, 0.31-0.34)
PON d 2 C6+	6	179 ± 2	176 ± 4	1.11 ± 0.051	0.63 ± 0.031
		(168, 164-173)	(174, 168-184)	(1.06, 1.03-1.22)	(0.62, 0.55-0.72)
PON d 2 C6-	5	174 ± 3	169 ± 2	1.07 ± 0.111	0.63 ± 0.071
		(167, 159-170)	(171, 166-176)	(1.20, 0.81-1.26)	(0.67, 0.47-0.75)
PON d 4 C6+	6	172 ± 2	167 ± 3	1.20 ± 0.071	0.72 ± 0.051
		(181, 174-187)	(169, 161-173)	(1.29, 1.19-1.35)	(0.76, 0.74-0.84)
PON d 4 C6-	6	177 ± 9	175 ± 3	1.10 ± 0.051	0.62 ± 0.021
		(165, 176-190)	(177, 167-183)	(1.09, 0.95-1.11)	(0.60, 0.56-0.67)
PON d 8 C6+	8	167 ± 4	163 ± 4	1.33 ± 0.081	0.82 ± 0.051
		(165, 159-176)	(160, 157-173)	(1.30, 1.24-1.38)	(0.80, 0.70-0.88)
PON d 8 C6-	9	167 ± 3	158 ± 2	1.32 ± 0.221	0.83 ± 0.041
		(165, 160-172)	(158, 152-166)	(1.30, 1.11-1.57)	(0.78, 0.72-0.95)

Data are expressed as mean ± SEM (median, inter-quartile range);

¹P < 0.05 compared to control group. PON: Protein-overload nephropathy; BW: Body weight; KW: Kidney weight.

Table 3 Markers of proliferation and apoptosis in the experimental groups

Group	n	Cortical PCNA (%)	BrdU + TECs (cells/mm2)	TUNEL + TECs (Field 1)	TUNEL + TECs (Field 4)
Control	9	0 ± 0 (0, 0-0)	0.2 ± 0.0 (0.2, 0-0.2)	6.9 ± 2.5 (8, 0-11.2)	2.7 ± 2.1 (0, 0-5.6)
PON d 2 C6+	6	0.24 ± 0.061	8.8 ± 2.71	-	-
		(0.28, 0.13-0.36)	(8.9, 2.7-15.3)
PON d 2 C6-	5	0.21 ± 0.071	6.8 ± 3.11	-	-
		(0.18, 0.14-0.30)	(6.4, 0.6-13.2)
PON d 4 C6+	6	0.34 ± 0.081	4.6 ± 0.81	-	-
		(0.30, 0.09-0.48)	(5.2, 3.4-7.4)
PON d 4 C6-	6	0.19 ± 0.041	3.2 ± 0.51	-	-
		(0.18, 0.14-0.30)	(1.2, 1.7-3.7)
PON d 8 C6+	8	0.15 ± 0.051	2.4 ± 0.71	13.4 ± 3.3	10.0 ± 2.61
		(0.11, 0.03-0.16)	(3.1, 0-4.1)	(12.8, 5.6-16.8)	(9.6, 5.6-17.6)
PON d 8 C6-	9	0.09 ± 0.031	2.0 ± 0.71	11.4 ± 3.7	7.8 ± 2.8
		(0.08, 0.02-0.11)	(1.2, 0.1-3.7)	(9.6, 0-17.6)	(6.4, 0-16)

Data are expressed as mean ± SEM (median, Inter-quartile range);

¹P < 0.05 compared to control group; Field 1 was the sub-capsular cortex; Field 4 was the inner cortex/outer medulla. PCNA: Proliferating cell nuclear antigen; TUNEL: Transferase-mediated nick end-labeling; PON: Protein-overload nephropathy; TEC: Tubular epithelial cells.

Table 4 Assessment of tubulointerstitial injury in the experimental groups

Group	n	TEC height	TEC diameter	Protein cast/field	Interstitial ED-1/field
Control	9	82.3 ± 1.7	253.0 ± 3.7	0	9.4 ± 0.5
		(83.3, 78.0-87.0)	(256.6, 241.7-259.0)		(9.3, 8.4-10.6)
PON d 2 C6+	6	70.9 ± 5.21	312.1 ± 13.91	-	20.9 ± 1.61
		(69.4, 59.5-79.6)	(311.8, 279.4-343.4)		(20.1, 17.3-25.5)
PON d 2 C6-	5	76.6 ± 2.81	300.8 ± 8.21	-	14.5 ± 4.0
		(76.1, 66.6-80.6)	(308.7, 292.7-316.6)		(11.3, 9.3-17.6)
PON d 4 C6+	6	68.0 ± 2.31	309.0 ± 11.11	2.9 ± 0.5	29.6 ± 2.312
		(68.3, 60.8-71.5)	(296.8, 291.1-341.1)	(3.4, 2.8-3.7)	(28.3, 25.4-38.2)
PON d 4 C6-	6	67.8 ± 3.81	303.2 ± 12.61	2.2 ± 0.6	21.0 ± 1.81
		(69.3, 61.1-75.4)	(313.0, 275.7-324.2)	(1.5, 1.1-3.4)	(20.9, 16.7-23.9)
PON d 8 C6+	8	74.7 ± 2.712	304.0 ± 9.21	1.1 ± 0.33	73.5 ± 6.712
		(76.2, 71.0-78.9)	(295.5, 280.4-319.1)	(0.7, 0.5-1.4)	(78.0, 59.2-85.7)
PON d 8 C6-	9	70.0 ± 2.91	298.0 ± 3.81	1.5 ± 0.5	56.1 ± 7.81
		(67.7, 63.3-75.3)	(298.6, 289.8-308.1)	(1.2, 0.5-2.3)	(56.7, 38.9-80.1)

Data are expressed as mean ± SEM. The units for TEC height and TEC diameter are in arbitrary units.

¹P < 0.05 compared to control (median, Inter-quartile range);

²P < 0.05 when compared to PON day 2, C6⁺;

³P < 0.05 compared to PON day 4, C6⁺. PON: Protein-overload nephropathy; TEC: Tubular epithelial cell.