Background Cadmium (Cd) is an important cause of infertility among occupational workers. Thymoquinone (TQ) is a medical extract from Nigella sativa (NS) and is used as a natural remedy for many diseases because of its antioxidant and anti-inflammatory properties. Aim of the work The aim of the study was to study the histological, immunohistochemical, and biochemical effects of TQ on Cd-induced toxicity of Leydig cells in adult male albino rats. Materials and methods Forty adult male rats were included in the study and were divided equally into four groups: group I, group II, group III, and group IV. Group I was the control group. Group II received a daily oral dose of Cd at 0.5 mg/kg by means of a gastric tube for 6 weeks. Group III received a daily oral dose of TQ at 100 mg/kg through a gastric tube for 6 weeks. Group IV received TQ, followed by Cd, at the same dose for 6 weeks. Specimens of the right testis were taken and processed for light microscopy (stained with H&E) and electron microscopy (stained with toluidine blue for semithin sections) to evaluate the structure of Leydig cells. Morphometric study of Leydig cells stained immunohistochemically by testosterone Ab-1 was carried out, and biochemical measurements of serum total testosterone and luteinizing hormone were taken, followed by statistical analysis. Results Microscopic study of group II showed apoptotic shrunken Leydig cells with deeply acidophilic cytoplasm and deeply stained nuclei, whereas electron microscopic results showed few mitochondria, few Smooth endoplasmic reticulum (sER), large cytoplasmic vacuoles, and heterochromatin margination. This was confirmed immunohistochemically by significant decrease in the area% of testosterone Ab-1 and biochemically by significant decrease in serum total testosterone and significant increase in serum luteinizing hormone. Group III showed similar results to group I, whereas group IV showed improvement in the histological, morphometric, and biochemical changes described for group II. Conclusion TQ has a protective effect on Cd toxicity-induced Leydig cell damage as it has antioxidant and anti-inflammatory activities. It is suggested that workers dealing with Cd consume a diet rich in TQ, such as Nigella sativa. |
