Investigation of the effects of tadalafil and vitamin C on glycerol induced muscle and kidney damage in rats by pathological and molecular methods

Crush syndrome is a critical clinical condition that occurs when muscle tissue is severely crushed as a result of traumatic events such as earthquakes or traffic accidents, and carries a high mortality risk. One of the most significant complications of this syndrome is acute renal failure, which develops as a result of the destruction of striated muscle cells. This study investigated the efficacy of tadalafil and vitamin C, administered alone and in combination, in the treatment of acute renal failure following experimental muscle injury induced by glycerol administration. Fifty randomly selected adult female Wistar albino rats were divided into seven groups: six animals in each control group (K:Control, Vitamin C:CK, Tadalafil:TK), and eight animals in each experimental group (Glycerol:G, Glycerol+Vitamin C:GC, Glycerol+Tadalafil:GT, Glycerol+Vitamin C+Tadalafil:GCT). To create muscle and kidney sections, after the experimental section was left dehydrated for 24 hours, 50% hypertonic glycerol solution (10 ml/kg, intramuscularly) was divided into two and added to both hind leg muscles, and the same volume of serum was given to the control compound. Vitamin C (20 mg/kg, oral gavage) and tadalafil (10 mg/kg, oral gavage) were administered at 24, 72, and 120 hours. On the sixth day, all rats were euthanized following blood collection under anesthesia. At the end of the experiment, the hindlimb muscles and kidneys of all animals were removed; the right kidneys were frozen in 10% formaldehyde solution for histopathological examination, and the left kidneys were frozen in liquid nitrogen and stored at −80 °C for Real-Time PCR analyses. Histopathological evaluation examined and scored renal tubular epithelial degeneration and necrosis, tubular luminal cylinder formation, tubular epithelial necrosis, luminal dilatation, glomerular atrophy, mononuclear cell infiltration and polymorphonuclear leukocyte infiltration. KIM-1, NGAL, PPARγ, and Cystatin C gene expression levels were determined in kidney tissue using real-time PCR. A significant decrease in body weight gain was observed in the experimental groups, along with a significant increase in relative organ weights (p<0.001). Histopathological examination of the kidneys revealed that the highest-scoring lesions occurred in the G group, while lesions decreased in the treatment groups, with the most significant decrease occurring in the combined group. The combined group had the closest renal score to the controls and was statistically significantly between the GC and control groups (p<0.001). Hyaline degeneration, Zenker necrosis, and myositis were found to be more severe in the muscle tissue of the G group, while the severity of the lesions decreased in the treatment groups, being more pronounced in the GT and GCT groups (p<0.001). Muscle regeneration was similar in all treatment groups. Real-Time PCR analysis revealed that Cystatin C expression levels were higher in the G group compared to the other groups, with the lowest levels found in the control group. PPARγ expression levels were highest in the control group and lowest in the G group. KIM-1 was noted to be highest in the G group and lowest in the control group. NGAL expression was also found to be highest in the G group, with the lowest values found in the TK group. These data suggest that the combination of vitamin C and tadalafil has a partial protective effect on oxidative stress and renal damage in myoglobinuric acute renal failure, but it does not fully restore the structural and functional integrity of the renal tissue. The findings highlight the supportive role of current treatments in rhabdomyolysis-induced acute renal failure and point to the importance of investigating different combinations of antioxidant and vasoprotective agents in the future.