Ultrastructural studies on the gastrocnemius tendon of selenium-deficient ducklings.

This paper presents an ultrastructural study of the changes occurring in the gastrocnemius tendon of normal and selenium-deficient ducklings from 1 to 12 days of age. The study revealed that the normal 1--8-day-old duckling tendon contained 2 morphologically distinct cell types and a third occurring at Days 8--12. The location of these cells within the endotendineum and fiber bundles and their morphologic characteristics are presented. Most cells showed cytologic alterations as early as 4 days on the deficient diet with progressive deterioration to Day 12. The various cell types showed a differential response to the deficiency. Changes included altered endoplasmic reticulum and Golgi apparatus and eventual cell rupture. The significance of these observations and their possible relationship to the etiology of selenium-deficiency-induced dystrophy is discussed.