Ultrastructure of skeletal muscle and peripheral nerve in experimental protein deficiency and its correlation with nerve conduction studies

Abstract

The effects of protein malnutrition on striated muscle and peripheral nerve were studied in the rhesus monkey by electron microscopy. Eight animals receiving a diet with practically no protein but with an adequate supply of calories and other nutrients constituted the test group; 3 animals fed on a similar diet but high in protein served as controls. Electron microscopy revealed marked thinning of the myofibrils with widening of the interfibrillar space and focal loss of myofilaments in protein-deficient animals. This change was marked after 9 weeks of protein deficiency. The peripheral nerves, after 9 weeks of protein deficiency, showed significant changes in myelin in the form of irregular thickening and infoldings of myelin sheaths; there were myelin nodules protruding into and apparently compressing the axis cylinders. The Schwann cells did not show any significant abnormalities. The ultramicroscopic findings in the peripheral nerves could be correlated with nerve conduction studies which showed slowing of motor nerve conduction velocity in protein-deficient animals.