Therapeutic potential of greenly synthesized selenium nanoparticles against experimental cyclosporiasis

Abstract

Cyclospora cayetanensis (C. cayetanensis), an opportunistic intracellular coccidian, is responsible for chronic debilitating diarrheal outbreaks possessing life-threatening penalties, especially in immunocompromised patients. The solemn therapeutic agents against cyclosporiasis are limited by their grave effects and high recurrence rate. The current study aimed to utilize greenly synthesized selenium nanoparticles (SeNPs) and evaluate their therapeutic efficacy on cyclosporiasis in immunosuppressed murine models. They were biosynthesized proficiently using Alcaligenes faecalis and characterized by assorted analytical techniques. After molecular confirmation of the parasite strain, immunosuppressed mice were infected with 10,000 C. cayetanensis sporulated oocysts. The anti-Cyclospora activity of seven-day oral treatment of 10 mg/kg of SeNPs was assessed through parasitological, ultrastructural, histopathological, and biochemical studies. The in vivo safety of SeNPs was assessed clinically, biochemically, and histopathologically. Parasitologically, SeNPs recorded the highest statistically significant decrease in the fecal oocyst burden (97.96%R) on the 30th day post-infection (PI). Scanning electron microscopic examination revealed remarkably deformed SeNPs-treated oocysts. SeNPs-treated mice exhibited impressive amelioration in intestinal architecture and inflammation, protracted to the 30th day PI. Colorimetric analysis revealed that SeNPs have recorded the highest serum reduced glutathione (GSH) level (300% increase) that swiftly repressed malondialdehyde (MDA) by 63.46%R. The present work has shed the first light on biogenic SeNPs as a safe, promising, proficient antioxidant nanotherapeutic for the treatment of experimental cyclosporiasis.

Keywords: Cyclospora cayetanensis; Anti-inflammatory; Antioxidant; Green synthesis; Scanning electron microscopy; Selenium nanoparticles.

Fig. 1

Visual monitoring (A) and optical properties (B) of bacterially synthesized SeNPs by Alcaligenes faecalis strain 46 N

Fig. 2

Structural and compositional properties of SeNPs synthesized by Alcaligenes faecalis strain 46 N: (A) XRD diffractogram and (B) EDX spectrography

Fig. 3

Morphological, functional, and surface charge features of SeNPs synthesized by Alcaligenes faecalis strain 46 N: (A) TEM micrograph (x10000 and accelerating voltage of 200 kV); (B) FTIR pattern; (C) PSD curve; (D) Zeta potential

Fig. 4

Melting curve of C. cayetanensis by qRT-PCR

Fig. 5

Light microscopy of C. cayetanensis oocysts retrieved from the stool of infected mice (n = 36) stained: (A) light pink to red with a mottled appearance by MZN stain (x1000); (B) orange by safranin stain (x1000)

Fig. 6

Scanning electron microscopy of C. cayetanensis oocysts recovered from stool of infected mice (n = 36): (A) Non-treated oocysts showing typical spherical shape with intact regular surface (x35,000); (B & C) CMX-treated oocysts revealing superficial irregularities and external protrusions, erosions and indentations (x35,000); (D-F) SeNPs-treated oocysts showed (D) distorted body with large protrusions (x35,000); (E) prominently enlarged polyps (x35,000); (F) shrunken body with extended surface lacerations (x35,000)

Fig. 7

H&E-stained intestinal sections of mice in the infected groups (n = 36). On the 14th day PI: (A&B) Non treated mice showing (A) reduction in villus height (thin arrow) and dense chronic lymphoplasmacytic and neutrophilic inflammatory infiltrate in the lamina propria (thick arrow) with focal epithelial erosions (x100); (B) increased intraepithelial lymphocytes (thin arrows) (x400); (C&D) CMX-treated mice revealing (C) improved villus architecture and height (thin arrows with asterisk) with less prominent inflammatory infiltrate in the lamina propria ( short thin arrows) (x100); (D) detectable intraepithelial lymphocytes (thin arrows) (x400); (E&F) SeNPs-treated mice displaying (E) increased villus height (thin arrows) and normal lamina propria without inflammatory infiltrate (x200); (F) intact surface epithelium with bland epithelial nuclei and no detectable intraepithelial lymphocytes (x100). On 30th day PI: (G) Non treated mice still showing supranuclear C. cayetanensis oocyst towards the apical surface of the intestinal epithelial cell (thin arrow) (x400); (H) CMX-treated mice demonstrating reappearance of lamina propria oedema and inflammation (thick arrow) and marked increase in intraepithelial lymphocytes (thin arrows) (x200); (I) SeNPs-treated mice presenting preserved villus architecture and height (thin arrows), intact surface epithelium and lack of intraepithelial lymphocytes (x200)

Fig. 8

H&E-stained ileum, liver and kidney sections of mice in non-infected SeNPs-treated mice (n = 6): (A) Ileal section revealing preserved villus architecture, intact surface epithelium and normal lamina propria with no signs of oedema or inflammation (x100); (B) liver section displaying normal hepatic architecture with hepatocytes arranged in cords radiating from central veins (x100); (C) Kidney section exhibiting well-preserved renal corpuscles, distinct organised renal tubules with no inflammation or necrosis (x100)