According to the results of the study, Vit C treatment mitigated existing liver damage caused by CLM application by regulating elevated liver enzymes, oxidative stress, apoptosis, and autophagy damage pathways.
Free radicals cause oxidative stress, which can lead to tissue damage 18,19. Increasing the production of reactive oxygen species (ROS) increases the oxidant capacity in parallel 20. Conversely, antioxidants found in the cell can neutralize free radicals, thus keeping ROS levels in balance 21,22. Consequently, if the antioxidant capacity decreases while the ROS level increases in the cell, oxidative stress is triggered 23,24. When oxidative stress occurs, it can damage the cell's lipid structure, protein content, and DNA 25. Lipids in the cell membrane are directly affected by increased ROS, and MDA levels increase simultaneously 26. Among antioxidant enzymes, SOD converts superoxide, an oxidative stress product, into hydrogen peroxide (H2O2). CAT breaks down H2O2 into oxygen and water, while GPx is effective in neutralizing both cytotoxic lipid peroxides and H2O2. The non-enzymatic antioxidant GSH reduces high ROS levels 27,28. It has been observed that CLM application increases MDA level, decreases CAT, GPx, SOD, and GSH levels, and consequently increases oxidative stress 29. Vit C, on the other hand, has the opposite effect, reducing oxidative stress.
Increased ROS levels increase NF-κB, which triggers inflammation, and IL-1β, a cytokine that NF-κB stimulates 30,31. Therefore, lowering NF-κB and the inflammatory cytokines it stimulates, L-1β and IL-6 levels, can reduce the inflammatory process 32. In this study, evaluated using rat liver, CLM administration increased NF-κB and IL-1β levels in tissues and increased inflammatory damage. Vit C, on the other hand, reduced all these effects of CLM.
Apoptosis is programmed cell death 33. Apoptosis typically occurs in healthy cells following cellular stress or injury 16. It is effective in removing cells damaged by increased free radical production and thus from the environment, and this occurs through the activation of caspases 34. P53, which plays a critical role in cell death caused by DNA damage, increases over time when DNA is damaged, phosphorylation occurs, and excessive proapoptotic reactions are triggered 35. The mitochondrial pathway plays a critical role in apoptosis processes. When the level of Bax, a pro-apoptotic protein, exceeds the levels of anti-apoptotic proteins, Bax translocates to the cytoplasm, thereby triggering apoptotic caspase activation 36,37. This study showed that CLM administration caused damage to rat liver tissues by increasing apoptotic factors and decreasing anti-apoptotic factors. CLM+Vit C administration reversed this situation. Vit C treatment showed protective properties against apoptotic damage caused by CLM administration in liver tissues.
Autophagy is a cell-to-cell degradation process induced by Beclin-1 and LC3A, involving the breakdown of unnecessary or damaged organelles and proteins within cells via lysosomes 38. Autophagy is also induced by oxidative stress 39. An excessive increase in autophagy levels causes tissues and organs to lose their function 40. Therefore, autophagy plays a crucial role in adaptation and cellular immunity 41. Vit C, on the other hand, has shown protective properties against autophagic damage by reducing CLM-derived LC3A and Beclin 1 levels 42. The CLM application triggers autophagy by increasing the amount of free Beclin-1 through phosphorylated Bcl-2. This, in turn, causes CLM to influence autophagy as a "damaging process" 43.
The liver is a vital organ with a crucial function: removing toxic substances from the body 44. AST and ALT enzymes are liver biomarkers. High levels indicate both disruption of the integrity of the cell membranes of liver tissue and liver damage. Increased serum AST and ALT enzyme levels occur as a result of the leakage of these enzymes into the blood due to the disruption of membrane integrity following damage or necrosis of hepatocytes 24. In the present study, increased serum AST and ALT levels with CLM administration indicate that CLM causes toxic damage to liver tissue. A decrease in serum AST and ALT levels was observed with CLM+Vit C administration. Thus, Vit C administration had a protective effect against the toxic effects of CLM on the liver.
This study presents clinically significant potential for Vit C treatment in CLM-induced hepatotoxicity. Pathological processes caused by CLM led to severe damage in rat liver. Vit C administration mitigated these negative changes 45. In medical practice, the application of Vit C in the treatment of serious damages such as hepatotoxicity stands out as an effective method that accelerates tissue healing by reducing oxidative stress, inflammation, and apoptosis. Our study has demonstrated the supportive effects of Vit C on tissue healing through its protective effects on cellular proliferation, apoptotic damage, and inflammation 26. The findings of the study suggest that Vit C can be incorporated into medical treatment protocols and may be an adjunct treatment option, particularly in acute conditions such as liver damage.
Consequently, based on the findings of the current study, it was observed that CLM causes toxic damage in rat liver tissues by activating oxidative stress, apoptosis, inflammation, and autophagic damage pathways. In contrast, Vit C treatment showed protective properties against CLM toxic damage by reducing the effects of all these damage pathways. Vitamin C achieved this protective effect by maintaining the Bax/Bcl-2 balance.
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