Morphological changes in rat rectus abdominis muscle induced by diabetes and pregnancy

Abstract

The urethral muscle of diabetic pregnant rats is affected by long-term mild diabetes and short-term severe diabetes, which plays a crucial role in the pathogenesis of pelvic floor disorders. We hypothesized that muscles outside the pelvis are subject to similar changes. The current study aimed at analyzing the effects of long-term mild and short-term severe diabetes on the structure and ultrastructure of fiber muscles and collagen in rats' rectus abdominis (RA) muscle. Therefore, the RA muscle of virgin, pregnant, long-term mild diabetic, short-term severe diabetic, long-term mild diabetic pregnant and short-term severe diabetic pregnant 3-month-old Wistar rats were collected. The structure was analyzed by picrosirius red staining, immunohistochemistry for fast and slow muscle fibers and transmission electron microscopy. We investigated two levels of STZ- induced diabetes: long-term mild diabetes (blood glucose level: 120–200 mg/dL) and short-term severe diabetes (blood glucose level >300 mg/dL). Long-term mild diabetic pregnant and short-term severe diabetic pregnant rats had decreased fast fibers and increased slow fibers, disrupted areas of sarcomere, intermyofibrillar mitochondria and myelin figures in the RA muscle. Both groups enabled us to analyze the specific influence of pregnancy, separately from diabetes. The current study demonstrated that diabetes and pregnancy induced intramuscular transformation and reorganization of RA muscle with a switch of fiber type adjusting their architecture according to intensity and duration of hyperglycemic insult within pregnancy.

Alterations in the structural characteristics of rectus abdominis muscles caused by diabetes and pregnancy: A comparative study of the rat model and women

“…The consequences of UI persist not only during pregnancy but up to 2 years post-partum and have a negative impact on the quality of life [14,15]. Previously, our research group conducted studies on the urethral tissue obtained from a pregnant Streptozotocin (STZ) rat model [16][17][18][19][20][21]. The hyperglycemia status in these rats is manifested by STZinduced necrosis of the pancreatic β-cells [22].…”

“…A higher or lower hyperglycemic level caused an impairment of the urethral tissue [17,18,20]. We also investigated the changes in rectus abdominis muscle (RAM) in the same animal model and discovered that both the RAM and urethral muscles are subjected to similar morphological changes during diabetic myopathy [21].…”

“…The RAM is a typical glycolytic muscle with a predominance of fast fibers [21]. The increase in its abdominal content during pregnancy represents a chronic physiological stimulus in the muscle fibers of the abdominal wall [23].…”

“…The increase in its abdominal content during pregnancy represents a chronic physiological stimulus in the muscle fibers of the abdominal wall [23]. During pregnancy, there is an increase in the abundance of slow fibers in the RAM, enabling it to be stretched [21,23]. This stretching is hypothesized to be a result of an overload of hypertrophy, contributing to muscle tone and endurance [23].…”

Study protocol to investigate biomolecular muscle profile as predictors of long-term urinary incontinence in women with gestational diabetes mellitus

“…In conclusion, these experimental results demonstrated that both long-term mild hyperglycemia and short-term severe hyperglycemia negatively impacted the muscle health in rats. RAM is subjected to similar structural changes related to pregnant diabetic myopathy [25,26,28] with intramuscular transformation and reorganization in fiber types [30][31][32].…”