The kidneys assume a pivotal role as primary targets susceptible to toxicity induced by chemicals owing to their integral involvement in the removal of harmful substances and their byproducts (Nassan et al. 2021). Numerous therapeutic agents have been documented for their tendency to cause nephrotoxicity during clinical usage (Perazella 2018). Genta, a frequently prescribed aminoglycoside antibiotic, is widely recognized as a significant contributor to drug-induced kidney damage (Randjelović et al. 2017). In this situation, the current study aimed to examine the potential nephro-protective effects of Clop in cases of kidney injury induced by Genta. This study represents the first to emphasize the role of Clop in alleviating nephrotoxicity caused by Genta.
In the present investigation, rats administered Genta displayed indications of kidney toxicity, as indicated by an increase in relative kidney weight, elevated serum Cr, BUN, Cyst-c, and urine GGT levels, and a reduction in Cr Cl. Furthermore, pronounced renal histological changes were observed, including necrosis of renal lining epitheliums, severe degenerative alterations, and necrosis of adjacent glomeruli. Additionally, extensive leukocytic infiltration in the interstitial areas was markedly evident. These results agree with previous studies that have shown similar results (Sharawy and Serrya 2020; Botros et al. 2022; Burgucu et al. 2022; Matouk et al. 2023; Nadeem et al. 2023).
Conversely, Clop showed significant enhancement in kidney functions, as manifested by a notable reduction in serum Cr, BUN, Cyst-c, and urine GGT levels, coupled with an enhancement in Cr Cl. These improvements were further supported by the positive changes observed in the histological examination. These findings align with earlier studies where the authors reported Clop's capacity to enhance kidney function in diverse animal models (Tu et al. 2008; Hu et al. 2011; Wu et al. 2022).
Multiple investigations have confirmed that Genta elevates markers of oxidative stress while reducing markers of antioxidants, providing evidence that oxidative stress contributes to the renal toxicity caused by Genta (Al-Kuraishy et al. 2020; Abdelkader et al. 2022; Matouk et al. 2023; Saeedavi et al. 2023). Genta accumulates in the renal proximal convoluted tubules, leading to degeneration of the brush border membranes, generation of free radicals, reduction in antioxidant defenses, and resultant manifestations such as congestion in glomeruli, acute necrosis in tubules, and eventual failure of the kidneys (Abdel-Raheem et al. 2009; Balakumar et al. 2010).
Reactive oxygen species (ROS) are exceedingly reactive molecules that exert significant effects on membrane lipids, nucleic acids, and intracellular proteins, causing alterations in their functions and structures and resulting in cellular damage (Özcan et al. 2015). MDA, a byproduct of lipid peroxidation, is known to disrupt enzyme activities, increase cell membrane permeability, disrupt the balance of intracellular ions by impacting the exchange of ions across the membrane, and induce breaks and modifications in DNA structure (Erçin et al. 2019). Conversely, Glutathione (GSH) assumes a crucial role in cellular maintenance. Thus, the reduction in renal GSH content may impede the body's defense against the elevated ROS levels induced by Genta. Similarly, Genta administration leads to renal oxidative damage by depleting antioxidant defense enzymes.
Renal oxidative damage ensues from Genta's induction of a deficiency in antioxidant defense enzymes. Additionally, Genta exerts nephrotoxicity by triggering the generation of cytokines that promote inflammation in the proximity of renal tissues (Qu et al. 2019). The crosstalk between ROS and inflammation becomes particularly significant in different toxicities and diseases. Persistent oxidative stress contributes to tissue damage, releases inflammatory mediators, and perpetuates a pro-inflammatory environment. Inflammatory responses are integral to the pathophysiology of acute renal failure (ARF), wherein the liberation of diverse cytokines into the damaged renal cells is pivotal for both the onset and advancement of ARF (Simmons et al. 2004; Ali et al. 2011) .
The current investigation found that Genta markedly elevated IL-1β and IL-6 levels, while reducing the expression of the anti-inflammatory cytokine IL-10 in the renal tissue of treated rats. These results suggest that inflammatory cytokines may be key players in the progression of Genta-induced proximal tubule dysfunction and nephrotoxicity. Interestingly, our findings contradict previous studies which reported a significant rise in pro-inflammatory cytokines IL-6 and IL-1β following Genta administration in renal tissue (Abdelkader et al. 2022; Bai et al. 2023; Nadeem et al. 2023). Additionally, our results confirmed the results observed by Samarghandian et al. (2015) (Samarghandian et al. 2015), who reported that injection of rats with Genta (100 mg/kg/ days) for 8 days caused a marked elevation in the expression of iL-6 and iL-1B as well as a reduction in the expression of anti-inflammatory cytokines Il-10 in renal tissue.
It has been documented that oxidative stress can activate various pro-inflammatory cytokines through the activation of NFκB (Sherif et al. 2015). NF-kB governs diverse cellular responses including innate immunity, inflammation and apoptosis (Kumar et al. 2015). Its expression is evident in renal impairment and inflammatory reactions (Ansari et al. 2017). Hence, the induction of NF-kB triggered by ROS could potentially contribute to nephrotoxicity induced by Genta.
In our investigation, we noted a significant increase in NF-kB levels in renal tissue of rats treated with Genta. These findings are consistent with a study by Nadeem et al. 2023 (Nadeem et al. 2023), where it was reported that administration of Genta for 10 consecutive days led to a notable elevation in NF-kB levels in the renal tissue of Genta-treated rats.
One of the pivotal discoveries of this investigation is the anti-inflammatory effect of Clop against Genta-induced nephrotoxicity. We observed that Clop led to a marked decrease in the expression of pro-inflammatory cytokines, IL-1β and IL-6, coupled with an increase in the expression of IL-10 in renal tissue. These results were confirmed by other previous studies in which the potent anti-inflammatory effects of Clop were reported (Yip et al. 2012; Khalaf et al. 2017; Ishimatsu et al. 2020; Chen et al. 2022). A notable discovery in our investigation was the observed reduction in NF-kB expression in renal tissue of rats injected with Genta upon treatment with Clop. Our findings align with those of Jia et al. 2019 (Jia et al. 2019), who descriped that Clop mitigates dysfunction in vein endothelial cells induced by LPS by inhibiting the NF-kB signaling pathway.
The inflammatory response due to the overproduction of ROS was not limited to the increased release of cytokines but also affected blood cells and caused an increase in WBC counts, called Leukocytosis. An extremely significant finding in our research is the marked elevation in WBCs and reduction in platelet count observed in Genta-treated rats. These findings are inconsistent with previous studies that confirmed the significant change in WBCs and platelet counts that appeared upon administration of Genta (Abhirama et al. 2018; Kondera et al. 2020; Aurori et al. 2023). On the contrary, pretreatment of animals with Clop caused a marked reduction in WBCs and caused renormalization to platelet counts.
Leukocytes, inflammatory cells, offer valuable insights into the detection of inflammatory diseases and the characterization of inflammation regarding its severity and type.(Tvedten and Raskin 2012). Furthermore, emerging studies suggest that platelets are implicated in inflammation, infection, host response, and cancer.
Platelets express adhesion molecules and secrete them to facilitate their accumulation at damaged sites. These molecules promote platelet adhesion to leukocytes and granulocytes. Additionally, platelets release chemotactic immune modulators that attract neutrophils, monocytes, and lymphocytes. This interaction leads to the formation of platelet-granulocyte or platelet-leukocyte aggregates, amplifying inflammation (Semple et al. 2011; Morrell et al. 2014). Thus, platelets have emerged as essential regulators of inflammation in various diseases (Semple et al. 2011).
Furthermore, thrombocytopenia may indicate inflammation as platelets are recruited to inflamed sites and adhere to white blood cells, thereby enhancing their activity and forming aggregates. Consequently, the circulating platelet count decreases (Seymour et al. 2016). Following recruitment from the bloodstream to sites of endothelial injury and inflammation, platelets were traditionally perceived as stationary cells. They adhere tightly and aggregate at the vessel wall, generating adhesive forces that activate fibrinogen. This activation subsequently triggers fibrin deposition and the formation of fibrin clots (Mackman et al. 2007). These consequences lead to thrombosis formation and interrupt blood flow which provides nutrition and oxygen to cells, ultimately culminates in cellular death (Chu 2005). Our findings demonstrated that pretreating rats with Clop before caused a marked reduction in Fibrinogen and fibrin deposition compared to Genta-treated rats.
The present study also revealed the significance of apoptosis in Genta-induced renal injury. Genta administration led to a substantial increase in both caspase-3 and pro-apoptotic BAX expression, coupled with a notable decrease in anti-apoptotic Bcl-2 expression, suggesting activation of the apoptotic pathway in Genta-induced renal injury. Previous research has documented comparable results (Abouzed et al. 2021; Laorodphun et al. 2022; Nadeem et al. 2023). Conversely, Clop demonstrated renoprotective effects by attenuating the overexpression of caspase-3 and BAX, while enhancing Bcl-2 expression. These findings are consistent with various investigative experiments highlighting the anti-apoptotic activity of Clop (Hu et al. 2011; Yip et al. 2012; Abouzed et al. 2021).