The absorption of a local haemostatic agent--Surgicel [elevated R]:an in vivo biochemical and histologic investigation in the rat

Abstract

SurgicelR, an absorbable haemostatic gauze, is claimed to consist of oxidized regenerated cellulose. It is a polyanion, the functional unit of which is termed polyanhydroglucuronic acid. The ability of tissues to absorb Surgicel, the tissue responses it evokes, and its inherent haemostatic properties have been extensively studied by a number of investigators. However, the mechanisms of absorption of Surgicel are unknown. The objectives of the present investigation were: (1) To determine the time period required for absorption of Surgicel in rat muscle. (2) To establish techniques for positive identification of the material in sections obtained for optical microscopy, using Alcian Blue. (3) To identify the ultrastructural morphology of Surgicel using transmission electron microscopy. (4) To investigate the mechanisms of resorption/absorption of Surgicel in rat muscle. Young, female Sprague-Dawley Albino rats were used as the experimental animals. Teflon tubes, containing the test material, were implanted into muscles of the anterior chest wall and animals were sacrificed at time periods ranging from 6 hours to 7 days postimplantation. Recovered tubes were: (1) Biochemically assayed for the presence of uronic acid. (2) Processed for optical microscopy and either sta i ned conventionally for histologic examination or sta ined with Al ci an Blue at different electrolyte conce ntrations. (3) Processed for transmission electron microscopy. Results of this invest i gation indicated that: (l) Surg i cel consists of at least two active components. These are (a) a soluble uronic acid component which i s absorbed after 6 hours post-impiantation and (b) a fibrous component which pers i sts. The latter materi al resembl es Surgicel in t he el ectron microscope and is sti ll evident at the implantation site 48 hours postimplantation. Moreover, Surgicel can be characterized in vitro into at least two components according to its so lubil ity under dissociative salt conditions (4M guan idinium chloride) . A residual fi brous material cou ld be hydro l yzed with 0.3N sodium hydroxide. (2) Surgi cel, an ana l ogue of tissue pol ya ni ons such as hya luronic acid and chondroitin s ul phate , can be se l ectively stained using Alcian Blue 8GX at a magnesium ch loride concentration of 0. 15M. (3) It appears that absorpt i on of the sa lt-sol uble uronate in vivo is effected by early extracellular degradation and/or systemic c learance whilst removal of the fibrous mater i al requires macrophage phagocytosis.