Pomegranate Juice Alleviates Preeclampsia Symptoms in an L-NAME-Induced Rat Model: A Dose-Dependent Study

Abstract

Objective: This study aimed to evaluate the dose-dependent therapeutic effects of pomegranate juice on preeclampsia symptoms using an L-NAME-induced rat model. Methods: Pregnant rats (n = 5/group) were assigned to a negative control group or groups receiving L-NAME to induce preeclampsia, with pomegranate juice administered at low, medium, and high doses from gestation day 7 to 20. Maternal parameters, including body weight, systolic blood pressure, urinary protein, and sFlt-1 levels, were monitored. Kidney and placental histology were assessed on gestation day 20. Results: L-NAME successfully induced preeclampsia symptoms, including significant maternal weight gain, hypertension, proteinuria, and increased sFlt-1 levels. Pomegranate juice administration alleviated these symptoms in a dose-dependent manner. High doses significantly prevented weight gain from gestation day 14, reduced the systolic blood pressure from gestation day 16, and lowered proteinuria and the sFlt-1 levels by gestation day 18, achieving values comparable to those of normal pregnant controls. Medium doses showed a moderate improvement, particularly in later gestational stages, while low doses had minimal effects. Pomegranate juice also enhanced placental health by increasing the labyrinth depth and reducing endocapillary hypercellularity, contributing to higher fetal and placental birth weights. The dose-response analysis indicated that the kidneys exhibited a stronger response to pomegranate juice than the placenta, suggesting different sensitivity thresholds. Conclusions: Pomegranate juice alleviates preeclampsia symptoms in a dose-dependent manner, significantly improving maternal weight regulation, blood pressure, and proteinuria. The therapeutic effects of pomegranate juice are attributed to its high phenolic content, which reduces sFlt-1 and improves placental function. These findings support pomegranate juice as a potential natural intervention for preeclampsia management.

Keywords: hypertension; placenta; pomegranate juice; preeclampsia; proteinuria.

Figure 1

Experimental design and timeline of measurements. The figure illustrates the experimental setup, including the grouping of pregnant rats and the schedule of treatments and measurements.

Figure 2

L-NAME-induced preeclampsia-like features and the effects of pomegranate juice on maternal health parameters. (A) Maternal body weight across gestation days 6, 10, 14, 18, and 20. Comparison between the control group, L-NAME group (preeclamptic control), and pomegranate juice-treated groups (low, medium, and high doses). (B) Systolic blood pressure measurements across gestation days 6, 10, 14, 18, and 20, showing the progression of hypertension in preeclamptic rats and the effects of pomegranate juice in reducing blood pressure. (C) Urinary protein concentration as an indicator of proteinuria across gestation days 6, 10, 14, and 18. Elevated levels in the L-NAME group indicate preeclampsia, while pomegranate juice administration reduces proteinuria in a dose-dependent manner. Data are presented as mean ± standard deviation (SD) and were analyzed by one-way ANOVA followed by Tukey’s post hoc test (p < 0.05; n = 5 per group). Groups bearing different superscript letters on the bars exhibited significant differences (p < 0.05).

Figure 3

Effects of pomegranate juice on sFlt-1 levels, fetal weight, placental weight, and placental index in pregnant rats with L-NAME-induced preeclampsia. (A) sFlt-1 concentration (ng/mL) in maternal serum on gestation day 20. L-NAME significantly increased the sFlt-1 levels compared to the control group, while pomegranate juice administration reduced the sFlt-1 levels in a dose-dependent manner. (B) Fetal weight (g) on gestation day 20. L-NAME-treated rats exhibited significantly lower fetal weights compared to controls. High-dose pomegranate juice significantly improved the fetal weight. (C) Placental weight (g) on gestation day 20. Preeclamptic rats showed a reduced placental weight, which was partially restored by high-dose pomegranate juice treatment. (D) Placental index (%) on gestation day 20. No significant differences were observed among the groups, indicating that the placental weight changes were proportional to the fetal weight changes. Data are presented as the mean ± standard deviation (SD) and were analyzed using one-way ANOVA, followed by Tukey’s post hoc test (p < 0.05). Different superscript letters indicate statistical significance (p < 0.05) between the groups.

Figure 4

Histopathological analysis of placentas from pregnant rats with L-NAME-induced preeclampsia, with or without pomegranate juice treatment. (A) Representative histological images of placentas stained with hematoxylin and eosin (H&E), showing the placental labyrinth (L) and junctional zone (JZ). (B) Quantification of placental parameters, including labyrinth depth (top graph), junctional zone depth (middle graph), and labyrinth-to-junctional zone ratio (bottom graph). L-NAME significantly reduced the labyrinth depth compared to the control group (p < 0.05), while pomegranate juice treatment improved the labyrinth depth in a dose-dependent manner (p < 0.05). No significant differences were observed in the junctional zone depth or the labyrinth-to-junctional zone ratio among the groups (p > 0.05). Data are presented as mean ± standard deviation (SD) and were analyzed using one-way ANOVA, followed by Tukey’s post hoc test (p < 0.05). Different superscript letters indicate statistical significance (p < 0.05) between groups.

Figure 5

Histopathological analysis of renal tissue in pregnant rats with L-NAME-induced preeclampsia, with or without pomegranate juice treatment. (A) Representative kidney sections (left, scale bar: 200 μm; right, scale bar: 50 μm) stained with H&E, demonstrating endocapillary hypercellularity, a marker of renal damage in preeclampsia. The area highlighted by the yellow frame in the left image is shown at higher magnification on the right. (B) L-NAME-treated rats exhibited significantly increased endocapillary hypercellularity compared to the control group (p < 0.05). Pomegranate juice administration, particularly at high doses, significantly reduced endocapillary hypercellularity compared to the L-NAME group (p < 0.05). Data are presented as mean ± standard deviation (SD) and were analyzed using one-way ANOVA, followed by Tukey’s post hoc test (p < 0.05). Different superscript letters indicate statistical significance (p < 0.05) between groups.

Figure 6

Dose–response analysis of pomegranate juice’s effects on placental labyrinth depth and kidney injury scores in L-NAME-induced preeclampsia. (A) The left panel illustrates the dose–response curve for the placental labyrinth depth, showing a sigmoidal increase with an IC₅₀ of 10.22 mg TPC/kg, indicating that a lower pomegranate juice dose is sufficient to achieve 50% of the maximal improvement in the placental structure. (B) The right panel depicts the dose–response curve for renal injury (endocapillary hypercellularity score), demonstrating a sigmoidal decline with an IC₅₀ of 20.92 mg TPC/kg, suggesting that a higher pomegranate juice dose is required to achieve a 50% reduction in renal damage. Data points were derived from experimental groups receiving different pomegranate juice doses (low, medium, and high) and fitted using a non-linear regression model. The difference in IC₅₀ values between the placental and renal responses highlights the organ-specific sensitivity to pomegranate juice treatment, with the placenta exhibiting a more pronounced response at lower doses, whereas the kidney requires a higher concentration for significant histological improvement.