title: Role of substance P in renal injury during DOCA-salt hypertension.
abstract: Substance P (SP), a neurokinin-1 receptor (NK-1R) agonist, is mainly produced and stored in primary sensory nerves and, upon its release, participates in cardiovascular and renal functional regulation. This study tests the hypothesis that activation of the NK-1Rs by SP occurs during hypertension induced by deoxycorticosterone (DOCA)-salt treatment, which contributes to renal injury in this model. C57BL/6 mice were subjected to uninephrectomy and DOCA-salt treatment in the presence or absence of administration of selective NK-1 antagonists, L-733,060 (20 mg/kg·d, ip) or RP-67580 (8 mg/kg·d, ip). Five weeks after the treatment, mean arterial pressure determined by the telemetry system increased in DOCA-salt mice but without difference between NK-1R antagonist-treated or NK-1R antagonist-untreated DOCA-salt groups. Plasma SP levels were increased in DOCA-salt compared with control mice (P < 0.05). Renal hypertrophy and increased urinary 8-isoprostane and albumin excretion were observed in DOCA-salt compared with control mice (P < 0.05). Periodic acid-Schiff and Masson's trichrome staining showed more severe glomerulosclerosis and tubulointerstitial injury in the renal cortex in DOCA-salt compared with control mice, respectively (P < 0.05). Hydroxyproline assay and F4/80-staining showed that renal collagen levels and interstitial monocyte/macrophage infiltration were greater in DOCA-salt compared with control mice, respectively (P < 0.05). Blockade of the NK-1R with L-733,060 or RP-67580 in DOCA-salt mice suppressed increments in urinary 8-isoprostane and albumin excretion, interstitial monocyte/macrophage infiltration, and glomerulosclerosis and tubulointerstitial injury and fibrosis (P < 0.05). Thus, our data show that blockade of the NK-1Rs alleviates renal functional and tissue injury in the absence of alteration in blood pressure in DOCA-salt-hypertensive mice. The results suggest that elevated SP levels during DOCA-salt hypertension play a significant role contributing to renal damage possibly via enhancing oxidative stress and macrophage infiltration of the kidney.
authors.affiliation: Central Laboratory and Division of Cardiology, First Affiliated Hospital, Henan University of Traditional Chinese Medicine, Zhengzhou 450000, China.
authors.forename: Youping
authors.initials: Y
authors.lastname: Wang
authors.forename: Donna H
authors.initials: DH
authors.lastname: Wang
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D003900:Desoxycorticosterone / Q000494:pharmacology*; D006909:Hydroxyproline / Q000378:metabolism; D006973:Hypertension / Q000139:chemically induced*; D054833:Isoindoles / Q000494:pharmacology; D007668:Kidney / Q000293:injuries*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010880:Piperidines / Q000494:pharmacology; D018040:Receptors, Neurokinin-1 / Q000378:metabolism; D013373:Substance P / Q000502:physiology*; D013686:Telemetry / Q000379:methods; D013997:Time Factors
chemical_list: D054833:Isoindoles; D010880:Piperidines; D018040:Receptors, Neurokinin-1; C071693:7,7-diphenyl-2-(1-imino-2-(2-methoxyphenyl)ethyl)perhydroisoindol-4-one; C103788:3-((3,5-bis(trifluoromethyl)phenyl)methyloxy)-2-phenylpiperidine; D013373:Substance P; D003900:Desoxycorticosterone; D006909:Hydroxyproline