Chronic Ingestion of Bisphenol A and Bisphenol S Attenuated Contractile Activity of Rat Stomach and Small Intestine In-vitro

Abstract

Introduction: Bisphenol A (BPA) is a chemical used in synthesis of plastic. BPA seeps into food from the plastic containers used to store food items. Exposure to BPA is implicated as a causative factor for detrimental effects on fetal development and various body systems like endocrine, reproductive and immune. Few studies report that BPA ingestion impair small intestinal contractility in-vitro. Government organisations of many countries have probed into the matter and imposed regulations on marketing of BPA. To meet the terms with regulations on BPA, manufacturers are increasingly replacing BPA with Bisphenol S (BPS). BPS has been advertised as a safer substitute to BPA. The various ill effects on BPS are being explored but the effect on gut motility is less clear. Aim: To examine the effect of chronic ingestion of BPA and BPS on rat gut contractions in-vitro. Materials and Methods: Healthy male adult albino rats (175- 225 g) were fed BPA (50 mg/kg/day) or BPS (50 mg/kg/day) or vehicle (Dimethyl sulphoxide) for four weeks by oral gavage. The animals were gently restrained so that the head is immobilised by retaining the animal in an upright position. Gavage needle was passed along the side of the mouth and moved into the esophagus and towards the stomach. After four weeks, they were sacrificed and isometric contractions of gut muscle strips were recorded in an organ bath (maintained at 37±0.5°C) using force transducer, computerised polygraph (power lab 4ST) and chart-5 for Windows, ADI, Sydney, Australia. Results: Acetylcholine (Ach) (0.1-100 µM) evoked gut contractions in-vitro and the basal tone and maximum contractile tension increased in a concentration-dependent manner. However, in both the treated groups, the Ach induced contractions were significantly (p<0.05, two-way ANOVA) attenuated as compared to control (vehicle) group. When both the treated groups were mutually compared, the Ach response was found to be similar. The spontaneous intestinal contractions were significantly less (p<0.05, one-way ANOVA) as compared to control in both the treated groups, where as in gastric tissue, only BPA treatment could significantly diminish the spontaneous contractility. Conclusion: Chronic ingestion of both BPA and BPS may impair gut contractility indicating that BPS might not be a harmless substitute for BPA.

Keywords

• acetylcholine
• gut contractility
• plastic toxin