Sani Baimai; Sirorat Janta; Passara Lanlua; Amornrat Chookliang; Apichaya Niyomchan & Sirinush Sricharoenvej
Disturbances of sensory and motor nerve conduction velocity in the spinal cord as well as degenerated myelin sheaths are observed in diabetic patients and animal models. Indeed, oligodendrocytes (OLs), which are important neuroglial cells, generate myelin in the central nervous system. Spinal enlargement, including cervical and lumbar enlargements, innervates all limbs. Thus, the purposes of this study were to examine and compare the ultrastructural alterations of OLs in spinal enlargements of streptozotocin (STZ)- induced diabetic rats and controls. Thirteen male Sprague-Dawley rats were induced with STZ in citrate buffer and six control rats were injected with the same buffer solution. All rats were sacrificed after inductions at four (short-term DM) and twenty-four weeks (long-term DM). The selected spinal enlargements were processed for transmission electron microscopy. The OL alterations in both the cervical and lumbar enlargements were apparently the same. In short-term DM, the nuclei of OLs became swelled with chromatin clumping. Cytoplasmic organelles were moderately damaged. In long-term DM, OLs contained shrinkage nuclei with thick heterochromatin clumping. Severely degenerated mitochondria with disrupted cristae and broken membranes were observed. Moreover, distended and fragmented rough endoplasmic reticulum were observed, and large clear areas were present in the cytoplasm. Additionally, the loosening, splitting, and destruction of myelin lamellae were found. This study can provide important preliminary information about the alteration of OLs in the spinal cords of diabetic patients, which might be involve in the impairments of sensory and motor conduction velocities in these individuals.
KEY WORDS: Spinal enlargement; Oligodendrocyte; Myelin; Diabetes mellitus; Streptozotocin.
BAIMAI, SANI; JANTA, S.; LANLUA, P.; CHOOKLIANG, A.; NIYOMCHAN, A.; SRICHAROENVEJ, S. Altered oligodendrocytes in spinal enlargements of streptozotocin diabetic rats. Int. J. Morphol., 38(6):1606-1613, 2020.