Indigofera oblongifolia mitigates lead-acetate-induced kidney damage and apoptosis in a rat model

Abstract

This study was conducted to appraise the protective effect of Indigofera oblongifolia leaf extract on lead acetate (PbAc)-induced nephrotoxicity in rats. PbAc was intraperitoneally injected at a dose of 20 mg/kg body weight for 5 days, either alone or together with the methanol extract of I. oblongifolia (100 mg/kg). Kidney lead (Pb) concentration; oxidative stress markers including lipid peroxidation, nitrite/nitrate, and glutathione (GSH); and antioxidant enzyme activities, namely superoxide dismutase, catalase, GSH peroxidase, and GSH reductase were all determined. The PbAc injection elicited a marked elevation in Pb concentration, lipid peroxidation, and nitrite/nitrate, with a concomitant depletion in GSH content compared with the control and a remarkable decrease in antioxidant enzymes. Oxidant/antioxidant imbalance, Pb accumulation, and histological changes in the kidneys were successfully prevented by the pre-administration of I. oblongifolia extract. In addition, the elevated expression of proapoptotic protein, Bax, in the kidneys of the PbAc-injected rats was reduced as a result of I. oblongifolia pre-administration, while the hitherto reduced expression of the anti-apoptotic protein Bcl-2 was elevated. Based on the current findings, it can be concluded that I. oblongifolia successfully minimizes the deleterious effects in kidney function and histological coherence associated with nephrotoxicity by strengthening the antioxidant defense system, suppressing oxidative stress, and mitigating apoptosis.

Keywords: Indigofera oblongifolia; apoptosis; kidney; lead acetate; oxidative stress.

Figure 1

HPLC–DAD phenolic profiles for the IOLE recorded at 280 nm. Abbreviations: AU, arbitrary unit; DAD, diode array detector; HPLC, high-performance liquid chromatography; IOLE, Indigofera oblongifolia leaves extract.

Figure 2

Ameliorative effects of IOLE on Pb accumulation in the kidney tissue of rats treated with PbAc for 5 days. Notes: Values are given as mean ± SEM (n=7). ^aP<0.05, significant change with respect to control; ^bP<0.05, significant change with respect to PbAc for Duncan’s post hoc test. Abbreviations: IOLE, Indigofera oblongifolia leaf extract; PbAc, lead acetate; SEM, standard error of the mean.

Figure 3

Ameliorative effects of IOLE pre-administration on ureic acid, urea, and creatinine in rats exposed to PbAc for 5 days. Notes: Values are given as mean ± SEM (n=7). ^aP<0.05, significant change with respect to control; ^bP<0.05, significant change with respect to PbAc for Duncan’s post hoc test. Abbreviations: IOLE, Indigofera oblongifolia leaf extract; PbAc, lead acetate; SEM, standard error of the mean.

Figure 4

Ameliorative effects of IOLE pre-administration on mRNA expression of SOD2, CAT, and GPx genes in the kidney of rats exposed to PbAc for 5 days. Notes: Values are given as mean ± SEM (n=7). ^aP<0.05, significant change with respect to control; ^bP<0.05, significant change with respect to PbAc for Duncan’s post hoc test. Abbreviations: CAT, catalase; GPx, GSH peroxidase; GSH, glutathione; IOLE, Indigofera oblongifolia leaf extract; PbAc, lead acetate; SEM, standard error of the mean; SOD, superoxide dismutase.

Figure 5

Light micrographs of the kidney. Notes: (A) The normal histological feature of renal tubules and glomerulus in the control group. (B) Severe inflammation, extensive degeneration, cytoplasmic vacuolation, and congested glomeruli in the PbAc-treated group. (C) The normal histological structure of renal tubules and glomerulus in the IOLE group, similar to the control group. (D) The normal histological structure of renal tubules and glomerulus in the group IV, where the IOLE was pre-administered to PbAc. Some vaculated areas can be still seen, however (H&E, 400×). Abbreviations: H&E, hematoxylin and eosin; IOLE, Indigofera oblongifolia leaf extract; PbAc, lead acetate.

Figure 6

Ameliorative effects of IOLE pre-administration on mRNA expression of Bcl-2 and Bax genes in the kidney of rats exposed to PbAc for 5 days. Notes: Values are given as mean ± SEM (n=7). ^aP<0.05, significant change with respect to control; ^bP<0.05, significant change with respect to PbAc for Duncan’s post hoc test. Abbreviations: Bax, Bcl-2-like protein 4; Bcl-2, B-cell lymphoma 2; IOLE, Indigofera oblongifolia leaf extract; PbAc, lead acetate; SEM, standard error of the mean.

Figure 7

Changes in caspase-3 expression in rat renal cells after the administration of IOLE and PbAc for 5 days. Notes: (A) The normal histological feature of renal tubules and glomerulus in the control group with week immunostaining of caspase-3. (B) Alteration in the histological feature of renal tubules and glomerulus in the PbAc group with strong immunostaining of caspase-3. (C) The immunostaining of caspase-3 in the IOLE group, similar to that in the control group. (D) The immunostaining of caspase-3 in the group IV, where IOLE was pre-administered with PbAc, similar to that in the control group (400×). Abbreviations: IOLE, Indigofera oblongifolia leaf extract; PbAc, lead acetate.