Histological and Histochemical study of skeletal muscle in diabetes mellitus subjects

Abstract

Type 2 Diabetes Mellitus (T2DM) is associated with histological and histochemical changes in human skeletal muscle. The changes that occur in skeletal muscle play an important role in development in insulin resistance. However, the changes are still controversial. This is due to the variation of skeletal muscle response to the changes in T2DM. In normal human skeletal muscle, different groups of muscles in the same anatomic region display different fiber type profiles and sizes. Previous study found that T2DM affects more on skeletal muscle fibers of the lower limb than the upper limb. The objective of this study was to describe the variation of histological and histochemical changes occur among lower limb muscles (LLM); Tibialis Anterior (TA) muscle, Soleus (SOL) muscle and Gastrocnemius (GAST) muscle in T2DM subjects. Skeletal muscle tissues harvested from subjects undergone below knee amputation (BKA) surgery from each TA, SOL and GAST muscle. Tissues were stained with Hematoxylin & Eosin (H&E), Reduced Nicotinamide Adenine Dinucleotide-Tetrazolium Reductase (NADH-TR), Adenosine Triphosphatase (ATPase) and Periodic Acid Schiff (PAS) staining. Qualitative and histomorphometric analyses were carried out to determine the variation in muscle fiber morphology; fiber type distribution, fiber size diameter, oxidative capacity and intramuscular capillarization. Qualitative analysis showed histological features of vascular and neuropathic changes as evidence by atrophic fibers, angulated fiber, target fiber and fiber grouping in each muscle groups. Histomorphometric analysis of fiber type distribution showed percentage distribution of fiber type in TA muscle (T1:71%, T2:29%), SOL muscle (T1:64%, T2:36%) and GAST muscle (T1:60%, T2:40%). Two-Way ANOVA was conducted to explore the impact of muscle group and fiber type on fiber diameter. Muscle group and fiber type had significant effect on fiber diameter (p<0.05). Mean of fiber diameter were 32.83, 35.76 and 36.58 ?m; for AT muscle, SOL muscle and GAST muscle respectively and mean diameter of fiber type were 35.18 (T1F) and 35.58 (T2F). For oxidative capacity among 3 muscle groups, a Two-Way ANOVA showed there were significant effects of muscle groups and fiber type on oxidative capacity (p<0.05). Mean of oxidative capacity were 1.12, 1.07 and 1.11 O.D; for TA muscle, SOL muscle and GAST muscle respectively. Intramuscular capillaries quantification revealed no significant different among 3 muscle groups (p>0.05). Mean capillary density were 178, 221 and 214 for TA, SOL and GAST respectively. In conclusion, the present study showed there were some significant histological and histochemical variations among 3 muscle groups of lower leg in T2DM subjects.