SummaryAn intravenous catheter system for long-term (at least 6-8 weeks) parenteral nutrition of unrestrained rats is described. The apparatus is inexpensive and can be constructed from commonly available materials.
Keywords: Rat; Intravenous infusion; Parenteral nutritionFor investigations in the field of experimental parenteral nutrition and in particular for investigating tumour growth using different forms of nutrition, the rat-model described by Steiger, Vars & Dudrick (1972) has proved valuable. A disadvantage is that the method is quite elaborate and in particular that the stainless steel support for the catheter and the canvas harness are rather complicated. Several publications deal with the composition of i.v. nutrition and have proved their effectiveness (Birkhahn, Bellinger & Border, 1976;Brenner, Muller, Keller & Walter, 1984;Dalton, Tourraine & Wilson, 1969;Daly, Reynolds, Rowlands, Dudrick & Copeland, 1980;Davis, 1966;Jones & Hynd, 1981; Neuhauser, Gottman & Bassler, 1984; OramSmith, Stein, Wallace & Muller, 1977;Steiger, Vars & Dudrick, 1972;Stein et al., 1976;Sitren, Fisher & Ali, 1975;Terkel, 1972;Weeks & Davis 1964). This paper describes a catheter system for long-term intravenous infusion which is both inexpensive 'and simple to construct.
Materials and methodsAnimals 3-month-old male Sprague-Dawley rats, weighing approximately 400--500 g were obtained from Dr Ivanovas GmbH, KisslegglAlIgau, FRG.
Catheter assemblyThe finger supports were removed from a plastic tuberculin syringe and 4 holes drilled as shown in Fig. l(E). The barrel of a second tuberculin syringe was shortened to a length of 5 cm and 4 holes Received 12 November 1984. Accepted 18 February 1985 pierced in the finger supports on either side of the syringe barrel (Fig. l(B». A 16-cm length of silicone rubber tubing (Fig. 1(0)) (10 7 mm, 00 1·2mm) (Silastic: Dow Corning Corporation, Medical Products, USA) was fixed to the tip of a 22-G 'Abbocath' (Fig. 1(C) (Abbott Ireland Ltd, Sligo, Republic of Ireland) flexible cannula with cyanoacrylate glue. The luer mount of the 'Abbocath' was trimmed so that it could be inserted into the barrel of the tuberculin syringe and anchored in place with cyanoacrylate glue (Fig. l(A»
Implantation procedureThe rats were anaesthetized with ether. Under aseptic conditions a I-em long incision was made between the mandibular angle and the sternum, and the external jugular vein exposed by blunt dissection. The vein was dissected free of the surrounding connective tissue, and ligatures passed beneath it to aid exposure. A subcutaneous tunnel was formed anteriorly to the incision, to accommodate a loop of the catheter (Fig. 2), and the tunnel was then extended dorsally subcutaneously to the back of the neck. A second skin incision was then made, 1 em long and running across the neck. A subcutaneous pouch was produced by blunt dissection .of the margins of the neck skin incision, to enable subcutaneous placement of the finger support (see Fig. 2). The free end of the catheter was grasped by a small pair o...