Structural examination of Se-NPs/citric acid matrix
SEM examination of the prepared selenium/citric acid nanocomposite showed the heterogeneous shape of agglomerated needles and spheres with an average diameter of 200 nm (Fig 1). EDS examination showed the surface elements of carbon (64.72%), selenium (30.94%) and oxygen (4.34%), confirming the formation of citric acid in the nanocomposite. The combination of citric acid and selenium has many advantages for drug delivery. Selenium is an essential element that affects several physiological processes in the form of various selenoproteins. A moderate number of elements can prevent health problems by enhancing metabolism and boosting immunity
(Hosnedlova et al., 2018; Islam et al., 2023; Sadeghian et al., 2012). Hence, it contributes to a healthy life and increases average health. However, the element in its nanoform sheds its relative toxicity and is considered more appropriate for supplementation as a means of drug delivery or as an adjuvant to conventional medicine
(Ferro et al., 2021; Raza et al., 2022).
Effect of the combination of citric acid and selenium nanoparticles on antioxidant status
Malondialdehyde (MDA) is a low-molecular-weight end product formed during the decomposition of some lipid peroxidation products. MDA estimation can be regarded as a diagnostic index for the extent of lipid peroxidation and oxidative injury in tissue lipids. Therefore, the present study considered MDA as a marker of lipid peroxidation induced by CCl
4. Group II showed a significant increase in MDA levels by (812.69%) compared to the control group I. However, in group III, the combination of citric acid and Se-NPs significantly restored the MDA level by (24.34%) concerning group II (Fig 2).
Reduced glutathione (GSH) acts as a scavenger and enzyme-catalyzed antioxidant in the oxidative injury of different tissues. Therefore, GSH plays a major role in protecting biological structures and functions. In the present study, reduced glutathione (GSH) was used as a primary parameter to determine the antioxidant status of the kidneys of treated animals. Group II showed a decrease in GSH level of (24.09%) in group I, while the CCl
4 + Se NP-treated group III showed a (13.90%) decrease in GSH level compared to group II (Fig 2).
Selenium is an essential component of many enzymes, some of which have antioxidant properties. Animals that are deficient in this element are more vulnerable to harm from certain forms of oxidative stress
(Sobolev et al., 2018). In this study, we investigated the effects of Se-NPs, a powerful antioxidant, on the rat’s CCl
4-induced kidney damage and oxidative stress in an animal model. Our results indicated that Se-NPs exerted an ameliorative effect against CCl
4 nephrotoxicity. Our data confirm the formation of citric acid in the nanocomposite. The combination of citric acid and selenium has several advantages. These findings are consistent with those of a study conducted by Alhawiti, who found that citric acid and selenium nanoparticles have antioxidant, antibacterial and anticoagulant properties
(Alhawiti, 2022). The combination of selenium and citric acid increases selenium stability and reduces the presence of the selenite form of the element, which is harmful and is associated with increased apoptosis
(Fan et al., 2020; Hosnedlova et al., 2018; Nazýroðlu et al., 2017;
Qian et al., 2019). Therefore, we planned this study to determine whether this combination could ameliorate CCl
4-induced renal toxicity
in vivo. The combination of citric acid and Se-NPs replenished the activity of vital antioxidant enzymes and proteins, such as reduced glutathione in CCl
4 treated rats with greater efficacy.
Effect of the combination of citric acid and selenium nanoparticles on renal functions
Urea level is the most indicative marker of renal function. Interestingly, CCl
4 in Group II resulted in a significant increase in urea levels by (96.92%) compared to the control. However, the combination of citric acid and the combination of citric acid and Se-NPs in group III was found to demonstrate a decrease in its level by (20.31%) compared to group II (Fig 3). However, the urea concentration in Group III was still significantly higher than that in the control group.
Creatinine level is an indicator of renal function. The creatinine level increased by (35.63%) in group II after CCl4 injection. The combination of citric acid and Se-NPs decreased its level by (2.71%) in group III rats (Fig 3) compared to that in group II. However, no significant changes were observed in either group (II, III) compared with the control group. Statistical analysis revealed no significant changes in albumin concentrations during this study. However, its level was decreased by only (0.58%) in group II, while the combination of citric acid and Se-NPs enhanced it by (3.15%) in CCl
4 treated group III (Fig 4).
The critical parameters of kidney function (urea and creatinine), which were elevated in CCl
4 injected rats, tended towards normal values with the supplementation of the combination of citric acid and Se-NPs. Many previous studies have demonstrated a consistent relationship between nephrotoxicity and oxidative stress
(Wu et al., 2018). The results of our study on lipid peroxidation and renal function markers showed the same pattern
(AlBasher et al., 2020) reported that Se-NPs exhibit antioxidant properties. This study also confirmed that Se-NP supplementation could counter CCl
4-induced oxidative stress
in vivo.
Kidney histology
Examination of the histopathological sections revealed that CCl
4 induced severe deterioration in renal tissues compared to control rats. Dilated urinary space with partially shrunken glomeruli was observed in the CCl
4 group. The combination of citric acid and Se-NPs showed a noticeable improvement in the renal tissues, exhibiting the urinary space and glomeruli structurally comparable to that of the control rats (Fig 5). Histological scores further confirmed that the combination of citric acid and Se-NPs noticeably improved the renal microstructure in the tissue samples in several histological indices; however, inflammatory cells were also observed in the same group (Table 1).
The kidney is one of the prime targets for xenobiotic and toxic substances because its large share of blood flow gives it the capacity to concentrate these substances (
Timbrell and Barile, 2023). The glomerular hypertrophy in CCl
4-injected rats might be due to the proliferation of mesangial cells, which secrete more matrix as a defense mechanism. Furthermore, the blood capillaries appeared engorged with red blood cells and the urinary gap was obliterated in the kidney samples, as previously reported for indomethacin and piroxicam injections in rat animal models
(Ebaid et al., 2007; Good et al., 2023). Infiltration of inflammatory cells into the intertubular tissues accompanied the tubular injury observed in the present study, possibly to minimize the lesion. Treatment with CCl
4 also induced the infiltration of inflammatory cells in the target organ and kidney, similar to the induction of inflammation by indomethacin and piroxicam in rat as animal models
(Abd-Alla et al., 2022).
Moreover, histological analysis of the tissue sections and their scores confirmed that considerable improvement was observed after the administration of NPs in the CCl
4 treated group. Here, the combination of citric acid and Se-NPs were found to lower lipid peroxidation and increase the level of GSH compared to control rats. Our study is in accord of previously reported by
(Ansar et al., 2017) showing supplementation with Se-NPs attenuates hepatotoxicity more strongly than supplementation with Ag-NPs. The combination of citric acid and Se-NPs increases plasma glutathione peroxidase (GPx) activity
in vivo (Yanez-Lemus et al., 2022). Therefore, our study is the first to report that combining SeNP with citric acid as nanocomposites are effective in ameliorating the CCl
4- induced nephrotoxicity.
In addition, they exhibited much lower toxicity when assessed based on the LD
50, acute kidney injury and short-term toxicity. The findings of the present study suggest that nanoscale selenium, such as Se-NPs with citric acid, can act as an antioxidant with a significantly reduced risk of toxicity compared with elemental selenium
in vivo (Zambonino et al., 2023). The effect of Se-NPs on selenoenzyme upregulation is equivalent to that of selenite and Se-NPs, with a considerable decrease in acute toxicity
(Zambonino et al., 2023).