Abstract:
Lipids are essential in pregnancy homeostasis. Their reduction is associated with reduced birth
weight a major predisposing factor to diseases in adulthood. Citrus limon (lemon) Juice (CLJ) is
used in folkloric medicine to prevent nausea and miscarriage throughout pregnancy. The
hypolipidaemic property of CLJ has been reported in literature. This study was designed to
investigate the effects of CLJ and its major constituents; Oleic Acid (OA), Palmitic Acid (PA) and
Stearic Acid (SA), on placental efficiency and foetal morphometry in Wistar rats.
Citrus limon Linn. fruits were gotten from a farm in Ibadan and validated at Forestry Research
Institute of Nigeria (FHI No:110938). The CLJ was expressed from cut fruits, an aliquot was
evaporated to dryness to obtain the concentration and characterized using GC-MS. Analytical grade
of OA, PA and SA were used for the study. Twenty-five pregnant Wistar rats (100-120 g) were
grouped into five (n=5), treated orally with 1mL/kg distilled water (Control), 91.0mg/kg CLJ,
27.8mg/kg OA, 23.4mg/kg PA and 17.6mg/kg SA from Gestation Day (GD) 1 to 20. Animals were
anaesthetised using thiopental sodium. Non -survival caesarean section was done to obtain
placentas and foetuses. Foetal morphometry (weight, crown-rump length, abdominal
circumference) and placental thickness were determined using digital weighing scale and Vernier
calliper respectively. Placental lactogen (PL), Glucose Transporter-1 (GLUT-1) and Small Neutral
Amino Acid Transporter-1 (SNAAT-1) were quantified using ELISA. Placental histology was done
using H&E stain. Placental insulin receptor substrate-1 (IRS-1) and peroxisome-proliferating activated-receptor-gamma (PPAR-γ) expressions were assessed immunohistochemically. Data were
analysed with ANOVA at α0.05
The GC-MS of CLJ revealed 12 compounds of which OA (30.5%), PA (25.8%) and SA (19.4%)
were the most abundant. Female foetal weight reduced in CLJ and SA (2.1±0.1; 2.0±0.1g) relative
to control (2.5±0.1g). Crown-rump length reduced in CLJ, OA and SA in male (59.6±1.1; 57.0±2.4;
57.0±2.6mm, respectively) and female foetuses (59.2±1.7; 54.9±1.8; 59.1±1.7; 54.7±1.9mm,
respectively) relative to control (74.7±4.9; 74.5±3.1mm). Abdominal circumference reduced in
CLJ, OA, PA and SA in male foetuses (12.5±0.3; 12.5±0.3; 12.2±0.1; 12.5±0.4mm) relative to
control (13.5±0.3mm). Placental thickness increased in CLJ in male (3.3±0.1mm) and female
foetuses (3.6±0.1mm) relative to control (2.3±0.2; 2.2±0.2mm, respectively). Placental lactogen
reduced in CLJ, OA and SA male (0.5±0.1; 0.5±0.1; 0.3±0.0 ng/mL) relative to control
(1.5±0.5ng/mL). Citrus limon juice reduced PL in female (0.3±0.0 ng/mL) relative to control
(0.5±0.0ng/mL) and GLUT-1 in male (5.8±1.5ng/mL) and female (10.5±2.1ng/mL) relative to PA
(17.8±0.5; 16.5±3.7ng/mL). The SNAAT-1 reduced in CLJ, OA and SA in male (6.4±1.2; 7.6±0.5;
10.6±0.5ng/mL) relative to control and PA (16.2±4.7; 19.2±0.4ng/mL) in female (10.2±1.7;
6.1±1.0; 11.1±3.6ng/mL respective relative to control (18.1±2.1ng/mL). Placental sections from the
CLJ group showed infiltration of inflammatory cells and decreased fat deposition. Placental PPAR γ expression reduced in male CLJ and OA (6.7±0.2, 5.7±2.9%) relative to control (8.9±0.1%).
Placental IRS-1 expression reduced in female CLJ (7.9±0.1%) relative to control (3.0±0.1%).
Citrus limon juice reduced placental nutrient transporters and efficiency, thereby reducing foetal
morphometric indices. This effect which is pronounced in male foetuses is linked to the oleic and
stearic acids.
