Attenuation of impaired uterine contractile activity by ascorbic acid supplementation during early gestational variable stress exposure in Wistar rats

Abstract

Background: This study investigates the effect of ascorbic acid supplementation during early gestational variable stress exposure on stress markers and in-vitro contractile responses of the uterus.

Methods: Twenty nulliparous pregnant rats (180-200 g) were randomly divided into 4 groups of 5 each. Stressed animals were variably exposed to 6 non-habituating and painless stresses (sleep deprivation, predator exposure, immobility, rapid cage changes, noise, and foreign object). Treated groups received ascorbic acid supplementation orally (10 mg/kg bwt) with or without stress exposure while control group received normal saline only. Stress exposure and ascorbic acid treatment was during gestation days (GD) 1-8. Serum cortisol, oxidative biomarkers and in-vitro contractile responses of excised uterine tissue to acetylcholine, oxytocin, calcium chloride, potassium chloride, diclofenac, and magnesium were assessed. Statistical significance was taken at p<0.05.

Results: Ascorbic acid supplementation in stressed pregnant group significantly deceased (p < 0.05) MDA activity. Catalase activity was enhanced in ascorbic acid supplemented stressed group while serum cortisol levels were significantly (p < 0.05) reduced in ascorbic acid supplemented stressed group when compared to stress only exposed group. Concentration dependent contraction responses to acetylcholine, oxytocin, calcium chloride, and potassium chloride were significantly reduced in stressed only pregnant rats. Ascorbic acid supplementation in stressed group reversed these reductions. However, doses of diclofenac and magnesium showed no significant effect on relaxation responses across all groups.

Conclusion: Ascorbic acid supplementation during early gestational variable stress exposure attenuated impaired contractile functions of the uterus. Enhanced antioxidant enzymes and suppressed MDA activity appear to play a role in the modulation

Keywords: Variable stress, early gestation, uterine contractility, ascorbic acid, oxidative stress