MATERNAL ADMINISTRATION OF Citrus limon LINN. JUICE, OLEIC, PALMITIC AND STEARIC ACIDS REDUCE PLACENTAL EFFICIENCY AND FOETAL MORPHOMETRY IN WISTAR RATS

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.