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Inflammatory enzyme composition of the neonatal rat intestine: implications for susceptibility to ischemia
C A Musemeche1, S J Henning, J L Baker
1Department of Surgery, University of Texas Medical School, Baylor College of Medicine, Houston.
Insights
Neonatal rat intestine injury is influenced by feeding status. Fasting significantly increases xanthine oxidase (XO) and myeloperoxidase (MPO) levels, key indicators of inflammation and free radical production, especially in younger animals.
Area of Science:
- Biomedical Science
- Neonatal Physiology
- Gastrointestinal Research
Background:
- Neonatal intestinal immaturity is linked to ischemic injury.
- Limited data exist on age- and feeding-dependent susceptibility to neonatal intestinal ischemia.
Purpose of the Study:
- To investigate age- and feeding-dependent changes in xanthine oxidase (XO) and myeloperoxidase (MPO) levels in the neonatal rat intestine.
- To assess the impact of fed versus fasted states on these inflammatory markers.
Main Methods:
- Measurement of XO and MPO levels in Sprague-Dawley rats aged 1, 5, 10, 15, and 20 days.
- Rats were studied in fed and fasted (4 hours prior) states.
- Small intestine segments were homogenized and assayed for enzyme levels.
Main Results:
- Fasted rats showed significantly higher XO levels than fed rats across all ages.
- Peak XO levels occurred between days 5 and 10 in both groups.
- MPO levels were higher in fasted versus fed rats on day 1, decreasing with age.
Conclusions:
- Significant differences in intestinal XO and MPO levels exist between fed and fasted neonatal rats.
- Age-dependent variations in XO and MPO are pronounced.
- The impact of these enzyme levels on ischemic injury severity requires further investigation.
Abstract:
Recent evidence has suggested that the immaturity of the neonatal intestine may play a key role in the development of ischemic injury. However, relatively little data exist on the susceptibility of the neonatal intestine to ischemic injury at various ages especially in the fed versus fasted states. In this study, the levels of xanthine oxidase ([XO] an enzyme which is a known, major source of free radicals in postischemic tissue) and myeloperoxidase ([MPO] an index of tissue neutrophil infiltration) were measured in 1-, 5-, 10-, 15-, and 20-day-old Sprague-Dawley rats. Rats were divided into fed (n = 8/day) and fasted (n = 8/day) groups 4 hours prior to sacrifice. The entire small intestine was removed and divided into five segments: the duodenum, proximal jejunum, distal jejunum, proximal ileum, and distal ileum. The specimens were homogenized and assayed for XO and MPO levels. A significant increase in XO was observed in the fasted animals compared to the fed animals on all days. Peak levels in XO were observed in both groups from day 5 to 10. MPO levels were significantly higher in the fasted versus fed animals on day 1. MPO levels decreased as the animals aged. These data demonstrate dramatic differences in the levels of inflammatory enzymes of the newborn rat in the fed versus fasted states. Also, marked variations with age are seen in both XO and MPO. Whether the XO and MPO levels present at the time of ischemic insult affect severity of injury remains to be seen.