Toxicity of Dextran in Rats

Abstract

THE anaphylactoid reaction caused by dextran in rats has recently been studied by several investigators^1–3. We have found that after intradermal injections of dextran dissolved in physiological saline (in rats), Menkin's intravenous dye test⁴ shows a seepage of dye into the wheals when the concentration of commercial dextran (Macrodex, Pharmacia Inc.) is at least 10 µgm/ml. Moreover, it has been found that dextran preparations with highly branched molecular chains are more toxic than those with relatively unbranched chains. Dextran fractions of an average molecular weight of 10,000 cause a positive dye test only in concentrations of about 10 mgm./ml. Sulphuric acid esters of dextran⁵ do not cause increased capillary permeability. We have confirmed the previously reported increase in hæmatocrit values after intravenous injection of dextran³, and found that it is more or less completely prevented by antihistaminics, local anæsthetics and pretreatment with cortisone in high doses. The most potent inhibitor, however, is alloxan intravenously in a subdiabetogenic dose. 2,3-Dimercaptopropanol injected 30 min. before dextran has an inhibitory effect only in some experimental series. The factors causing these variations in the ‘antiphlogistic’ effect of BAL are under study.