Connective tissue repair in zinc deficiency. An ultrastructural morphometric study in perforated mesentery in rats

Abstract

Objective: To quantify measures of healing in zinc-deficient and healthy rats.

Design: Randomized study.

Material: 30 male Sprague-Dawley rats.

Interventions: Zinc deficiency was induced in half the rats. All rats underwent laparotomy and standard perforations were made in the small intestinal mesentery with a scalpel. At 1, 3, 5, 7 and 10 days after operation 6 rats were killed by overdose of anaesthetic agents and the specimens of the mesentery were fixed.

Main outcome measures: Measurement of cellular volume density, surface density of the rough endoplasmic reticulum, and surface density of the plasma membrane.

Results: Perforations started to close on day 4, and most were closed by day 10. Cellular volume density reached its peak between days 3 and 5, as did surface density of rough endoplasmic reticulum. There were no significant differences between the two groups for either measurement. The surface density of the rough endoplasmic reticulum, however, was significantly higher in controls than in zinc deficient animals on days 3-10 (p less than 0.001). The surface density of the plasma membrane was significantly higher in zinc-deficient animals on days 1-3 (p less than 0.04), and in control animals on days 5-10 (p less than 0.01).

Conclusions: Protein synthesis and formation of scar tissue were slightly lower in the zinc-deficient animals, and the higher plasma membrane surface density implies that contraction may be an important part of healing in the small intestinal mesentery in rats.