Feline Intestinal Ischemia and Reperfusion: Relation between Radical Formation and Tissue Damage

Abstract

Experimental ischemia of 15, 30, or 60min length, followed by 30 min of reperfusion, was produced in situ in the cat small intestine by means of an adjustable arterial clamp. Arterial perfusion pressure was lowered to such an extent that intestinal blood flow decreased from about 25 to 3.5 ml × min^–1 × 100 g^–1. The rate of free radical formation was followed intermittently with ESR and a modified spin trapping technique in the control period prior to ischemia and at various times during reperfusion. Upon reperfusion radical formation increased above the preischemic control value in all three series of experiments. Cumulative radical production during the 30 min reperfusion period rose from about 3 µmol × 100 g^–1 after 15 min ischemia to approximately 4.5 µmol × 100 g^–1after 30 min and 8-10 µmol × 100 g^–1 after 60 or 120 min ischemia. At the same time mucosal damage became more pronounced, suggesting a causal connection between tissue damage and radical formation. More specifically, radical production was strongly correlated to histological damage occurring during reperfusion as seen when comparing radical production in animals not experiencing reperfusion damage to those who did. Radical formation in these two groups were 0.35 and 9.0 µmol × 100 g^–1, respectively (p < 0.0005).

Quantification of tissue damage in the feline small intestine during ischaemia‐reperfusion: the importance of free radicals

“…The present report is based on experiments which have been or will be published (Nilsson et al 1993(Nilsson et al , 1994. In these publications the histological damage to the intestinal mucosa in connection with ischaemiareperfusion were analysed according to the grading system proposed by Chiu et al (1970).…”

“…The operative procedures have been described in detail previously (Nilsson et al 1989). Briefly, after anaesthesia the abdomen was opened by a midline incision and up to six segments of jejunum were isolated in situ with intact vascular supply.…”

“…However, the latter conclusions are based on indirect observations using pharmacological agents known to influence the formation of radicals. Recently, a method that makes it possible to estimate, in quantitative terms, the rate of radical formation in vivo has been developed in this laboratory (Nilsson et al 1989) which offers a more direct approach to the study of radical formation.…”

Lipid Peroxidation Products and Antioxidant Capacity in Portal Venous and Systemic Arterial Plasma during Gradual Intestinal Ischemia and Reperfusion in Pigs

“…Since all these have limitations in the assessment of lipid peroxidation, we used several assays to assess the systemic synthesis and release of radicals. Previous studies indicate that free radicals are important in the pathogenesis of the local intestinal damage [1,16], and elevated lipid peroxidation products have been demonstrated in intestinal tissue samples after gut ischemiareperfusion [17][18][19][20]. In the model of total occlusion of the superior mesenteric artery elevated systemic plasma levels of malondialdehyde were observed in rats [17].…”

Central and Paracentral Visual Field Defects and Driving Abilities

“…Although PCS have been reported in infections with herpes viridae, AIDS, Lyme disease and secondary syphilis, they are almost always monocular and, with the exception of AIDS, progression is now rare [8, 28, 35, 57, 67, 102, 113, 124, 133, 148, 219]. The implications for driving have not been studied.…”