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IL‐6 Infusion Increases Mean Arterial Pressure in Mice with Reduced Renal Mass
Author(s) -
Lee Dexter L.,
Sturgis LaShon C.,
Pollock Jennifer S.,
Brands Michael W.
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a1184-b
Subject(s) - mean arterial pressure , medicine , kidney , nephrectomy , urology , blood pressure , endocrinology , anesthesia , heart rate
Chronic infusions of IL‐6 or tumor necrosis factor–alpha have been shown to increase mean arterial pressure (MAP) in pregnant, but not normal rats. Because pregnancy is associated with significantly increased renal blood flow and workload, we tested the hypothesis that IL‐6 would increase MAP when renal mass is surgically reduced, to cause increased single nephron flow and workload in a non‐pregnant model. Male C57BL/6 mice were divided into three groups (WT, RRM Vehicle (V) and RRM+IL‐6) and implanted with biotelemetry devices to measure MAP 18 hrs/d. In two groups, RRM V and RRM+IL‐6, the poles of one kidney were surgically removed. After two weeks of recovery, contralateral nephrectomy (~ 70% total reduction in renal mass) was performed during transmitter surgery. Baseline MAP was 100 ± 5 mmHg for WT mice and 129 ± 5 mmHg for the RRM mice. An osmotic minipump (s.c.) was used to administer IL‐6 for six days. By day 4 of IL‐6 infusion, MAP had increased 13 ± 7 mmHg in RRM+IL‐6 mice. The RRM V MAP decreased 9 ± 3 mmHg below baseline levels, and WT+IL‐6 mice MAP did not change from baseline levels. On day 6, the change in MAP was 14 ± 8 mmHg above baseline for RRM+IL‐6, 9 ± 5 mmHg below baseline in RRM V, and still unchanged in WT animals. The 16 ng/hr IL‐6 infusion increased plasma IL‐6 from 18 ± 3 to 26 ± 4 pg/mL. These data suggest that increases in plasma IL‐6 elevate MAP when renal mass is reduced. It is not known, however, if that is due to some consequence of high single nephron flow, or due to the effect of RRM per se on the pressure natriuresis relationship. (HL7416, HL56259, HL75625, T32‐HL66993)