Protective effects of nanocurcumin against stress-induced deterioration in the intestine

Abstract

The therapeutic activities of curcumin have long been investigated in some chronic and inflammatory diseases. This study was designed to investigate the protective effects of nanocurcumin on intestinal barrier function, apoptosis, and oxidative stress in rats exposed to traffic noise. Forty rats were divided into four groups: two traffic noise-exposed groups of animals that received either vehicle (NOISE) or nanocurcumin (NCUR + NOISE) and two control groups that either remained intact (CON) or received nanocurcumin (NCUR). Nanocurcumin injection (15 mg/Kg/ip) and traffic noise exposure were administered daily for two weeks. The relative protein expression of intestinal tight junctions, occludin, and ZO-1 and Bax/Bcl-2 ratio was measured to evaluate barrier integrity and apoptosis in intestinal samples, respectively. Plasma D-lactate concentration was examined as a criterion of intestinal permeability. Corticosterone, superoxide dismutase (SOD) activity, glutathione (GSH), total antioxidant capacity (TAC), and nitrite were measured in serum. The noise exposure increased Bax/Bcl-2 ratio, corticosterone, and oxidative stress in the NOISE animals. Nanocurcumin treatment improved the Bax/Bcl-2 ratio and reduced corticosterone and oxidative stress in the NCUR + NOISE animals. The expression of tight junction proteins was decreased while the concentration of D-lactate was increased in the NOISE animals. Nanocurcumin did not efficiently impact the expression of tight junction proteins and the D-lactate level in the NCUR + NOISE group. Nanocurcumin administration displayed antioxidant and anti-apoptotic roles in the noise-exposed rats, however, it did not affect the intestinal barrier integrity. We concluded that reduced apoptosis in the intestine might be related to the antioxidant activity of nanocurcumin and its modulatory effects on the HPA axis in the nanocurcumin-treated animals.

Keywords:

• Nanocurcumin
• stress
• oxidative stress
• apoptosis
• tight junction
• intestine

Acknowledgments

The present study was supported by a grant devoted to Fatemeh Nabavizadeh from Tehran University of Medical Sciences. We cordially thank the Physiology Research Center, Kashan University of Medical Sciences for collaborating in implementing this project.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Tehran University of Medical Sciences [grant numbers 47903].

Notes on contributors

Azam Alinaghipour

Azam Alinaghipour, Ph.D, graduated from the Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. She is interested in the gut-brain axis, focusing on the mechanisms involved in changing the permeability of the intestinal epithelial barrier and the blood brain barrier.

Mahmoud Salami

Mahmoud Salami, Ph.D, Professor of Physiology and Head of the Physiology Research Center, Institute for Basic Sciences, Kashan University of Medical Sciences, Kashan, Iran. He is pursuing a line of research on the potential use of probiotic supplementation to treat neurodegenerative disease, focusing on the gut-brain axis.

Esmail Riahi

Esmail Riahi, Ph.D, Associate Professor at Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. He is pursuing a line of research on the potential use of deep brain stimulation (DBS) to treat intractable substance use disorders.

Ghorbangol Ashabi

Ghorbangol Ashabi, Ph.D, Associate Professor at Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. She has experience in cerebral injuries, focusing on molecular pathways.

Masoud Soheili

Masoud Soheili, Ph.D, Researcher of Physiology Research Center, Basic Sciences Research Institute, Kashan University of Medical Sciences, Kashan, Iran. His research focuses on neurodegenerative disease and the gut-brain axis, particularly identifying the relevant biochemical and histopathological mechanisms.

Fatemeh Nabavizadeh

Fatemeh Nabavizadeh, Ph.D, Professor of Physiology and Head of Electrophysiology Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran. Her research mainly focuses on the gastrointestinal tract, especially gastrointestinal cancers using animal models.