Systemic Lupus Erythematosus (SLE) in MRL/lpr Mice

We routinely run systemic lupus erythematosus (SLE) in MRL/lpr mice at Hooke. Because it clinically resembles SLE in human patients and is relatively short (10 weeks), this is the most commonly used model of SLE.

MRL/lpr mice are homozygous for spontaneous mutation in the Fas gene, and develop lymphadenopathy (enlarged lymph nodes), splenomegaly (enlarged spleen), anti-nuclear and anti-dsDNA antibodies, and systemic autoimmunity. Autoimmune responses occur spontaneously in these mice, resulting in glomerulonephritis and arthritis resembling SLE in human patients.

We run this model in female mice; treatment usually starts when mice are 11 weeks old. By 19 weeks of age, ~85% of untreated mice will develop kidney pathology - usually studies end at that point.

Our standard in vivo readouts are proteinuria and body weight, each measured weekly.

At the end of the study, we measure spleen weight, perform histological analysis of kidneys, and measure anti-dsDNA antibodies and blood urea nitrogen (BUN) in serum. We can also perform immunofluorescence analysis of kidneys and evaluate IgG and C3 presence in the kidney cortex (glomeruli). Spleens can be evaluated histologically to determine the follicle area as a proportion of the spleen area.

Autoimmune responses such as production of anti-nuclear antibodies are detectable as early as 8 weeks of age. Extensive kidney pathology is found at 16 to 30 weeks of age.

Please contact Hooke at or with questions or for a quotation.

Typical results

Mice were treated from week 11 of life (Week 11) through the end of the study (Week 19). Proteinuria was measured once weekly from Week 10. Serum was collected at Weeks 11 and 16 for anti-dsDNA IgG antibody measurement, and at Week 19 for anti-dsDNA IgG antibody and BUN measurement. Kidneys were collected at the end of the study for histological analysis.

All figures show mean + or ± SEM, and all tables show mean ± SD.

Clinical readouts

Treatment	# mice	End proteinuria score	p value
Vehicle	13*	3.38 ± 0.77	-
Cyclophosphamide	10	2.25 ± 0.42	<0.001

*Two (2) mice were euthanized due to complications of lymphadenopathy.
End proteinuria scores compared using Wilcoxon's non-parametric test.

Tissue weights at termination

Treatment	Kidney (mg)*	p value	Spleen (mg)	p value
Vehicle	233 ± 51	-	496 ± 249	-
Cyclophosphamide	191 ± 32	0.036	116 ± 37	<0.001

Kidney and spleen weights compared using 2-tailed Student's t-test.
*Average of both kidneys.

BUN and anti-dsDNA measurements

Treatment	BUN in serum (mg/dL)	p value
Vehicle	58.4 ± 76.8	-
Cyclophosphamide	11.0 ± 5.0	0.066

BUN in serum concentrations compared using 2-tailed Student's t-test.

anti-dsDNA IgG (units/mL)
Treatment	Week 21 (baseline)	Week 16	p value	Week 19 (terminal)	p value
Vehicle	68 ± 69	147 ± 142	-	183 ± 135	-
Cyclophosphamide	68 ± 69	28 ± 18	0.016	23 ± 6	0.001

Anti-dsDNA antibody concentrations compared using 2-tailed Student's t-test.

Histological analysis of kidneys at termination

Kidney histological analysis - Total glomerular lesion

Kidney histological analysis - Total tubular and interstitial lesion

Kidney histological analysis - Total kidney lesion

Histological analysis of kidneys at termination
Treatment	Total glomerular lesion	p value	Total tubular and interstitial lesion	p value	Total kidney lesion	p value
Vehicle	5.2 ± 3.7	-	2.2 ± 1.8	-	7.4 ± 5.0	-
Cyclophosphamide	0.3 ± 0.7	<0.001	0.3 ± 0.5	<0.001	0.6 ± 0.8	<0.001

Kidney lesion scores compared using Wilcoxon's non-parametric test.

Periodic acid-Schiff (PAS) staining

Illustrative images of Periodic acid-Schiff staining in kidneys

For a higher resolution image, click on the image above. Scale bars are 250 µm. Insets illustrate kidney transverse sections at the hilus (kidney cut in half, both halves embedded and sectioned), with red outlines indicating the locations of the magnified images.

Histological analysis of spleens at termination

Mice were treated from Week 11 through Week 19. Spleens were collected for histological analysis at the end of the study (Week 19).

Spleen histological analysis - Follicle area of tissue area

Histological analysis of spleens at termination
Treatment	n	Follicle area of tissue area (%)	p value
Vehicle	15	71.5 ± 8.2	-
Cyclophosphamide	15	61.1 ± 11.1	0.009

Follicle areas of tissue areas compared using 2-tailed Student's t-test.

Hematoxylin and eosin staining

For a higher resolution image, click on the image above. Scale bars are 500 µm. Insets illustrate transverse sections of spleens (spleen cut in half, both halves embedded and sectioned) with red outlines indicating the locations of the magnified images.