The Potential Effect of Polysaccharides Extracted from Red Alga Gelidium spinosum against Intestinal Epithelial Cell Apoptosis

Abstract

Gut injury is a severe and unpredictable illness related to the increased cell death of intestinal epithelial cells (IECs). Excessive IEC apoptotic cell death during the pathophysiological state entails chronic inflammatory diseases. This investigation was undertaken to assess the cytoprotective action and underlying mechanisms of polysaccharides from Tunisian red alga, Gelidium spinosum (PSGS), on H₂O₂-induced toxicity in IEC-6 cells. The cell viability test was initially carried out to screen out convenient concentrations of H₂O₂ and PSGS. Subsequently, cells were exposed to 40 µM H₂O₂ over 4 h in the presence or absence of PSGS. Findings revealed that H₂O₂ caused oxidative stress manifested by over 70% cell mortality, disturbed the antioxidant defense, and increased the apoptotic rate in IEC-6 cells (32% than normal cells). Pretreatment of PSGS restored cell viability, especially when used at 150 µg/mL and normal cell morphology in H₂O₂-callenged cells. PSGS also equally sustained superoxide dismutase and catalase activities and hindered the apoptosis induced by H₂O₂. This protection mechanism of PSGS may be associated with its structural composition. The ultraviolet visible spectrum, Fourier-transformed infrared (FT-IR), X-ray diffraction (XRD), and high-performance liquid chromatography (HPLC) demonstrated that PSGS is mainly sulfated polysaccharides. Eventually, this research work provides a deeper insight into the protective functions and enhances the investment of natural resources in handling intestinal diseases.

Keywords: Gelidium spinosum; antioxidant; apoptosis; intestinal epithelial cells; polysaccharides.

Figure 1

UV–visible absorption Spectrum of polysaccharide PSGS.

Figure 2

IR spectrum of the polysaccharide PSGS.

Figure 3

X-Ray Diffraction of PSGS.

Figure 4

Monosaccharide composition analysis by HPLC−FID of PSGS.

Figure 5

(A) Toxicity test of PSGS on cell viability of IEC-6 cells (% of control), (B) Effects of H₂O₂ on cell viability of IEC-6 cells (% of control), (C) Effects of PSGS on cell viability in H₂O₂-injured IEC-6 cells (% of control).NG (Normal group) HG (treated group with H₂O₂) Error bars represent standard deviations of three replications. Bars marked with (*) are significantly different from the normal group at * p < 0.05; *** p < 0.001.

Figure 5

(A) Toxicity test of PSGS on cell viability of IEC-6 cells (% of control), (B) Effects of H₂O₂ on cell viability of IEC-6 cells (% of control), (C) Effects of PSGS on cell viability in H₂O₂-injured IEC-6 cells (% of control).NG (Normal group) HG (treated group with H₂O₂) Error bars represent standard deviations of three replications. Bars marked with (*) are significantly different from the normal group at * p < 0.05; *** p < 0.001.

Figure 6

Photomicrographs demonstrating morphological changes of IEC-6 cells for different treatments (A) normal; (B) model (H₂O₂ 40 µM,4 h arrows indicating changes in cell shape); (C) pretreated with PSGS 20 µg/mL for 4 h then exposed to 40 µM of H₂O₂ for 4 h.

Figure 7

(A) Effects of PSGS on levels of SOD in H₂O₂-injured IEC-6 cells, (B) Effects of PSGS on levels of CAT in H₂O₂-injured IEC-6 cells. NG (normal group), HG (model group treated with H₂O₂). Error bars represent standard deviations of three replications. Significant differences between the treated groups and the normal group were mentioned as follows: *** p < 0.001.

Figure 8

Effect of PSGS on H₂O₂-induced apoptosis. NG (normal group) HG (treated group with H₂O₂). Error bars represent standard deviations of three replications, Significant differences between the treated groups and the control were mentioned as follows: * p < 0.05.

Figure 9

Location of the collection zone (the coastal area of Sidi Jmour, Djerba, Tunisia).