The Pharmacology of Inflammation DEMO

Measurement of Oedema Formation

Experiments in the United Kingdom would have to be carried out according to the research establishments ethical and welfare guidelines and also under the Animal (Scientific Procedures) Act 1986. Experiments carried out in other countries would have to be carried out according to local laws and ethical / welfare committee guidelines. The procedure is carried out under anaesthetic and is therefore not associated with pain.

In these experiments male New Zealand White rabbits (2-3kg) were anaesthetised with sodium pentobarbitone (30-4Omg/kg i.v.).

The dorsal skin was shaved and a site pattern marked with up to 12 injection sites in each section. The test agents were randomised and then allocated according to a balanced site pattern, to enable each combination of agents to be injected once into each block.

¹²⁵I-albumin (1.5Ci/kg) and Evans Blue (0.5ml/kg of 2.5% w/v) were injected intravenously.

Test agents were made up in saline and injected in 0.1ml volumes into the shaved dorsal skin according to a balanced site pattern with six replicates per dose. After a 30min accumulation period each rabbit was killed by a barbiturate overdose.

The dorsal skin was removed and injection sites punched out. Oedema responses were expressed as equivalent plasma volumes by dividing each skin sample count by the count of 1µl plasma

There are several other methods of measuring oedema formation:

1. In studies where the microcirculation is observed directly (intravital microscopy) fluorescent dextrans can be used for quantitative studies and carbon black can be also be used to determine the site of extravasation, as originally carried out by Majno.
2. In some studies such as rat paw or human skin, the volumes or thickness of swelling can be measured directly.
3. Methods such as ultra sound and magnetic scanning techniques are also under development.