Acute and Chronic Iron Overloading Differentially Modulates the Expression of Cellular Iron-homeostatic Molecules in Normal Rat Kidney.

Little is known about the renal responses to acute iron overloading. This study measured the renal tubular expression of transferrin receptor-1 (TfR1), cubilin/megalin receptors, hepcidin, ferroportin, and ferritin chains following subacute intoxication of 40 male Wistar rats with a single oral dose of ferrous iron (300 mg/kg). The animals were randomly subdivided into 4 equal subgroups at the time of necropsy (1, 2, 4, and 8 hr). The results were compared with the controls ( n=15) and with the chronic group ( n=15), which received iron for 4 weeks (75 mg/kg/day; 5 days/week). Although both toxicity models inhibited TfR1, they upregulated the cubilin/megalin receptors and hepcidin, and triggered iron deposition in tubular cells. The ferritin heavy-chain and ferroportin were downregulated in the 2-hr and 4-hr acute subgroups, whereas chronic toxicity promoted their expression, compared with controls. Moreover, the 4-hr and 8-hr subgroups had higher intracellular Fe+2 and marked cell apoptosis compared with the chronic group. In conclusion, the kidney appears to sustain iron reabsorption in both intoxication models. However, the cellular iron storage and exporter proteins were differentially expressed in both models, and their inhibition post-acute toxicity might contribute toward the intracellular accumulation of Fe+2, oxidative stress, and ferroptosis.

Vitamin D alleviates lead induced renal and testicular injuries by immunomodulatory and antioxidant mechanisms in rats.

This study measured the effects of vitamin D (VD) supplementation on the underlying molecular pathways involved in renal and testicular damage induced by lead (Pb) toxicity. Thirty two adult male Wistar rats were divided equally into four groups that were treated individually or simultaneously, except the negative control, for four weeks with lead acetate in drinking water (1,000 mg/L) and/or intramuscular VD (1,000 IU/kg; 3 days/week). Pb toxicity markedly reduced serum VD and Ca2+, induced substantial renal and testicular injuries with concomitant significant alterations in the expression of VD metabolising enzymes, its receptor and binding protein, and the calcium sensing receptor. Pb also significantly promoted lipid peroxidation and pro-inflammatory cytokines (IL-4 and TNF-α) in the organs of interest concomitantly with declines in several anti-oxidative markers (glutathione, glutathione peroxidase and catalase) and the anti-inflammatory cytokine, IL-10. The co-administration of VD with Pb markedly mitigated renal and testicular injuries compared with positive controls. This was associated with restoration of the expression of VD related molecules, promotion of anti-oxidative and anti-inflammatory markers, but tissue Pb concentrations were unaffected. In conclusion, this report is the first to reveal potential protective effects for VD against Pb-induced renal and testicular injuries via anti-inflammatory and anti-oxidative mechanisms.

The fibrolytic potentials of vitamin D and thymoquinone remedial therapies: insights from liver fibrosis established by CCl4 in rats.

BACKGROUND: Vitamin D (VitD) and thymoquinone (TQ) are nutraceutical agents with well-known immunomodulatory and hepatoprotective properties. This study measured whether VitD and TQ, individually or combined, could have direct fibrolytic activities and/or enhanced performance during remedial treatment of liver fibrosis established by CCl4 in rats. METHODS: Eighty five male Wistar rats were used as 10 negative controls (NC) and the remainders were distributed equally into 5 groups: short (S-PC) and long (L-PC) positive controls, TQ, VitD and VitD/TQ groups. CCl4 was injected for 7 weeks followed by a week of no intervention. TQ and/or VitD were given orally (3 days/week) from week 9 and euthanasia was at week 17 for all groups except the S-PC was at week 9. Following histopathological and digital image analyses, TGF-ß1, IL-6, IL-10, IL-22 and MMP-9 were measured by ELISA in liver homogenates while the corresponding cytokine receptors were measured by immunohistochemistry. The mRNA expressions of all molecules were measured by quantitative RT-PCR. RESULTS: Fibrosis was evident in both PC-groups and was significantly more advanced in the L-PC than S-PC, reaching to cirrhosis. The concentrations of TGF-ß1, IL-6, IL-22 and their receptors were significantly higher (P < 0.05) simultaneously with significantly lower (P < 0.05) concentrations of MMP-9, IL-10 and IL-10 receptors in the S-PC and L-PC than the NC-group. TQ and VitD monotherapies showed significantly less fibrosis than L-PC but were similar to S-PC. Both remedial monotherapies also resulted in significant decreases of TGF-ß1, IL-6, IL-22 and their receptors together with significant increases of MMP-9 and IL-10 system compared with S-PC and L-PC groups. Interestingly, dual therapy resulted in the most significant improvement in fibrosis score and index, yet was significantly higher (P < 0.05) than the NC-group, and concurred with the utmost significant restorations of all candidate genes and proteins. CONCLUSIONS: VitD and TQ exhibited comparable anti-fibrogenic effects and modulated several pro- and anti-fibrotic mediators. Additionally, VitD/TQ dual therapy alleviated the previously established liver fibrosis simultaneously with significantly enhanced actions at the molecular level. More studies are required to explorer the therapeutic value of TQ and VitD against liver fibrosis in human.