Bioassay of Endotoxin Inactivation in the Lead-Sensitized Rat

Abstract

Lipopolysaccharides from gram-negative bacteria, i.e., endo toxins, when administered parenternally, induce profound cardiovascular collapse and ultimately lethality in shock in various animals ( 1 , 2). However, in comparison to other species, rats are highly resistant to the physiopathological effects of endotoxemia, e.g., Zweifach (3) has compiled the following relative LD75 for circulatory collapse: cat, 1; rabbit, 2.5; dog, 8; guinea pig, 20; and the rat, 300. Thus, despite the great utility of rats in various experimental shock models, the high resistance to endotoxin has detracted from use of rats in analysis of the cardiovascular events in endotoxin shock.Recently, Selye, Tuchweber, and Bert6k (4) reported that a single intravenous injection of lead acetate markedly sensitized rats to lethal endotoxin shock and suggested use of this synergism as a convenient bioassay for minute amounts of endotoxin. The present study evaluated the use of the lead-treated rat in the bioassay of the ability of rat organ homogenates to inactivate endotoxin.Methods. Male Sprague-Dawley rats of the Holtzman strain, with a body weight range of 300 -t-20 g, were maintained on Purina Chow and water ad libitum at a constant temperature of 24 t 1" for 7-10 days prior to use. Endotoxin was purchased from Difco Laboratories, Detroit, Michigan, as the Boivin lipplysaccharide preparation from Salmonella enteritidis. Endotoxin was prepared daily in 0.0% NaCl. Lead acetate (Mallinckrodt Chemical Works, St. Louis, Mo., No. 5684) was prepared daily in distilled water.Organs for homogenates were obtained from rats sacrificed by a stunning blow to the

A New Method for Biological Assay of Endotoxin Using Change in Peripheral Leukocyte Population in Mice as a Response

“…Recently, attempts at increasing susceptibility of experimental animals to endotoxin have been reported (Moon and Berry, 1968;Moon, 1972;Pieroni et al, 1970;.Filkins, 1970;Dowling and Feldman, 1970;Levin, Tomasulo and Osler, 1970;Wong ASSAY OF ENDOTOXIN USING LEUKOCYTE CHANGE et al, 1973). Studies on this subject are in progress (Kuratsuka et al, 1972 * The standard error , 0.155, given by Spaun et al (1945) was used for the calculation of the fiducial limits.…”

Endotoxin tolerance and polymyxin B modify liver damage and cholestasis induced by a single dose of α-naphthylisothiocyanate in the rat

“…Lead acetate as trihydrate salt (Sigma Chemical Co., St Louis, USA) was dissolved in pyrogen-free sterile distilled water (10 mg/ml) and administered to rats by intravenous injection in a single 5 mg dose (Selye et al 1966;Filkins 1970). Lipopolysaccharide (LPS) from Escherichia coli 026:B6 Boivin type or from Salmonella typhimurium Westphal type (Difco Laboratories, Detroit, USA) was prepared in sterile distilled water; 0.01 mg i.v.E, coli LPS or 5 rag/100 g body wt oral S. t~phimurium LPS were used.…”

Renal and Cardiovascular Effects of Chronic Occlusion of the Bile Duct in Rats

“…The presence of systemic endotoxemia was detected by two dif ferent methods: (I) the in vivo assay in lead-sensitized rats [9] and (2) the in vitro limulus lysate assay ("Pyrotcst', Difco). For the in vivo assay, groups of control or bile duct obstructed rats were given an intravenous injection of lead acetate (20 mg/kg) via the lateral tail vein and the mortality during the next 24 h was observed.…”