Comparative biomolecular analysis of normal and healed skin tissue from diabetic and non-diabetic rats using Raman spectroscopy.

Diabetes mellitus (DM) is a metabolic disorder characterized by chronic hyperglycemia that disrupts skin repair through alterations in tissue biochemical composition and structural organization. This study compared Raman spectral profiles of normal and healed skin tissue in non-diabetic (Non-Db) and diabetic (Db) Wistar rats, based on the hypothesis that diabetes alters skin molecular composition during healing. Twelve Wistar rats were divided into Non-Db and Db groups (n = 6 per group). DM was induced by of alloxan monohydrate injection (150 mg/kg). Dorsal skin excision was performed under anesthesia on day 0 (normal tissue) and day 14 (healed tissue), resulting in 24 samples. Raman spectra were acquired (830 nm excitation, 400-1800 cm-1 range, ~ 4 cm-1 resolution, 30 s integration time) in sextuplicate per sample. Data were analyzed by principal component analysis (PCA), followed by ANOVA or Kruskal-Wallis tests. The Raman spectra mainly characterized by features attributed to structural proteins and lipids from epidermal and dermal layers, including collagen, elastin, keratin, and amino acids, fatty acids, ceramides, phospholipids and cholesterol. PCA revealed group-dependent variations in protein- and lipid-associated bands. Increased in protein related features accompanied by a relative reduction in lipids contributions suggested disruption of protein-lipid balance during extracellular matrix remodeling, suggesting molecular alterations in healed skin tissue associated with DM. Raman spectroscopy showed changes in the biomolecular profile of skin healing in diabetic tissue compared with non-diabetic, evidencing a distinct repair pattern marked by modified collagen related features and enhanced membrane lipid signatures in healed diabetic skin.