Estrogen replacement therapy in OVX-STNx rats and its nephroprotective role against progression of renal failure

ABSTRACT

Inspite of estrogen replacement therapy being extensively used in clinical and experimental studies without renal impairment, there are no long-term studies concerning estrogen replacement in chronic renal failure. This study was performed to explore whether estrogen has a nephroprotective role against progression of renal failure. This study was carried out on 41 adult female albino rats, that were allocated into 3 groups; Group 1 [n = 10] sham-operated rats, that received the solvent [sesame oil] and used as control group, Group II [n = 17], ovariectomized-subtotal nephrectomized rats [OVX-STNx] without treatment, that received the solvent, group III [n = 14], OVX-STNx rats treated with estrogen, subcutaneous [s.c.] at a dose of 30 micro g/kg/day for 10 weeks, started on the second day after ovariectomy. Mean Blood pressure was measured on the day of sacrifice. Blood urea nitrogen [BUN], serum creatinine, malondialdehyde [MDA] and platelet aggregation were estimated. Kidneys were excised and examined histologically. The results of the present study showed that untreated OVX-STNx rats showed significant elevation in mean blood pressure compared to treated OVX-STNx rats [129 +/- 2.2 versus 97 +/- 3.2 mmHg]. The untreated OVX-STNx rats showed significant elevation in BUN and serum creatinine levels compared to sham-operated rats [85.9 +/- 4.0 versus 19.4 +/- 1.6 mg/dl; and 2.6 +/- 0.13 versus 0.16 +/- 0.02 mg/dl, respectively], while, the treated OVX-STNx group showed significant reduction in BUN and serum creatinine levels, compared to untreated OVX-STNx group [24.8 +/- 1.6 versus 85.9 +/- 4.0 mg/dl; and 0.38 +/- 0.04 versus 2.6 +/- 0.13 mg/dl, respectively]. In addition, serum MDA level was elevated in untreated OVX-STNx group compared to sham-operated and to treated group [6.6 +/- 0.4 versus 3.6 +/- 0.3 and 4.8 +/- 0.3 /micro mol/L, respectively]. Also, ADP-stimulated platelet aggregation showed significant reduction in untreated OVX-STNx group in comparison to sham-operated and to treated group [46.8% +/- 2.6 versus 76.5% +/- 1.8 and 65.1% +/- 3.6 respectively]. Histological examination of the remnant kidney models in untreated OVX-STNx group showed a picture of focal glomerulosclerosis, this finding was minimally seen in treated OVX-STNx group