A Master’s Study at the College of Medicine Investigates the Effects of Sleep Disturbances and Light Exposure During Sleep on Pancreatic Health

A Master’s thesis defense was held on Thursday, September 10, 2026, for Master’s student Salwa Hameed Afat from the Department of Human Anatomy, College of Medicine, Al-Nahrain University. The thesis was entitled:

“Evaluation of the Effect of Sleep Disturbance on Melatonin Receptors (MTNR1B) in Pancreatic Tissue of Adult Male Rats”

The study aimed to evaluate the effects of sleep disturbances induced by external light exposure, either through intermittent sleep disruption or reduced sleep duration, on the pancreatic tissue of male rats.

The results revealed histopathological changes, including dilation of blood vessels, cellular death, and the appearance of adipose tissue within the pancreatic tissue. In addition, a statistically significant reduction was observed in both the number and area of the islets of Langerhans in the sleep-disturbed groups compared with the control group, which maintained normal sleep patterns.

Furthermore, an immunohistochemical study of melatonin receptors demonstrated that these receptors were localized predominantly in the beta cells of the islets of Langerhans. No statistically significant differences were observed in melatonin receptor expression between the control group and the sleep-disturbed groups. This finding indicates that, despite the observed histopathological changes, melatonin receptor expression remained statistically unchanged. It further suggests that melatonin continues to exert its effects on pancreatic beta cells despite environmental alterations, such as external light exposure and sleep disruption, thereby potentially contributing to the maintenance and preservation of beta-cell integrity within the islets of Langerhans.

The study concluded that exposure to light during normal sleep periods has adverse effects on the body, including the pancreas. The endocrine component of the pancreas, particularly the insulin-secreting function, may be affected by this external stimulus, potentially contributing over time to the development of obesity, insulin resistance, and metabolic disorders.

The thesis defense committee consisted of:

• Prof. Dr. Thaer Mahmoud Farhan – Chair

• Prof. Dr. Malak Akram Taha – Member

• Assistant Lecturer Jalal Abdul-Ali Hamoudi – Member

• Assistant Professor Dr. Huda Rashid Kareem – Member and Supervisor

The thesis was successfully approved with a grade of Excellent.

Media and Government Communication Division
College of Medicine – Al-Nahrain University