Hippocampal neuron number loss in rats exposed to ingested sulfite

Abstract

Sulfite, which is continuously formed in the body during metabolism of sulfur-containing amino acids, is commonly used in preservatives. It has been shown that there are toxic effects of sulfite on many cellular components. The aim of this study was to investigate the possible toxic effects of sulfite on pyramidal neurons by counting cell numbers in CA1 and CA2-CA3 subdivisions of the rat hippocampus. For this purpose, male albino rats were divided into a control group and a sulfite group (25 mg/kg). Sulfite was administered to the animals via drinking water for 8 weeks. At the end of the experimental period, brains were removed and neurons were estimated in total and in a known fraction of CA1 and CA2-CA3 subdivisions of the left hippocampus by using the optical fractionator method--a stereological method. Results showed that sulfite treatment caused a significant decrease in the total number of pyramidal neurons in three subdivisions of the hippocampus (CA1 and CA2-CA3) in the sulfite group compared with the control group (p < 0.05, Mann Whitney U test). It was concluded that exogenous administration of sulfite causes loss of pyramidal neurons in CA1 and CA2-CA3 subdivisions of the rat hippocampus.

Curcumin, the Main Part of Turmeric, Prevents Learning and Memory Changes Induced by Sodium Metabisulfite, a Preservative Agent, in Rats

“…Many investigations have shown that sulfite may cause toxic effects for the nervous system. It has also been reported that the number of hippocampal neurons decreased in rats after exposure to sulfite [15]. Moreover, it was shown that sulfite increased the excitability of the spinal reflexes after sulfite treatment [16, 17].…”

Curcumin Can Prevent the Changes in Cerebellar Structure and Function Induced by Sodium Metabisulfite in Rat

“…These observations are in agreement with the previous studies showing the sulfite toxicity on neurons. For example, Akdogan et al [4] showed loss of pyramidal neurons in the subdivisions of the rat hippocampus caused by sulfite treatment. The rotarod apparatus has been used to evaluate changes in motor function caused by some pharmacological agents, such as tranquilisers and antidepressants and antianxiety compounds [21, 22].…”

“…The first and the second groups received distilled water and olive oil, respectively as the vehicles for sodium metabisulfite and curcumin. Besides, the third and fourth groups received sodium metabisulfite (25 mg/kg/day) and curcumin (100 mg/kg/day), respectively [4, 8, 10]. Finally, the fifth group received both sodium metabisulfite and curcumin in doses described above.…”

“…According to the studies of Akdogan et al [4] and Ribera et al [10] the time point was adopted. The study of Ribera et al 2001 was performed on the rats for 28 (subacute) and 85 (subchronic) days of dietary contact [4, 10]. The time point adopted here (56 days) was selected as the average time point which was considered for subacute and subchronic toxicities.…”

“…It has been shown that sulfite can induce toxic effects on neurons. For example, exposure to sulfite reduced the hippocampal neuron number in rats [4]. In addition, sulfite treatment increased the excitability of the spinal reflexes [5].…”