No abstract

Background. The association between hypothyroidism and renal diseases has been described in many studies. Nigella Sativa was among the recently reported natural product that has the potential to prevent renal tissue damage and fibrosis. The aim of this study was to evaluate the possible protective effect of thymoquinone on the structure of the renal cortex of hypothyroid rats and explore the mechanism behind it. Methods. An experimental model of hypothyroidism was induced in adult male Wistar rats by administration of propylthiouracil (6 mg/kg/body weight). One hypothyroid group was treated with thymoquinone at the dose of 50 mg/kg/body weight and compared to the untreated group. Thyroid function and oxidant/antioxidant status were assessed in the serum. Catalase gene expression was assessed using the real-time polymerase chain reaction. The kidney was assessed both histologically and immunohistochemically. Results. Administration of propylthiouracil resulted in a significant decrease in the serum levels of nitric oxide, reduced glutathione, and superoxide dismutase activity while the level of malondialdehyde significantly (p<0.001) increased. Administration of thymoquinone alleviated this effect on the thyroid hormones and significantly increased the serum levels of antioxidants. Thymoquinone significantly (p<0.001) upregulated catalase transcription by about 24-fold and could block the hypothyroidism-induced glomerular and tubular injury. Conclusion. Thymoquinone may have a potential protective effect against hypothyroidism-induced renal injury acting through the attenuation of the oxidative stress and upregulation of renal catalase gene expression.

As our previous studies have indicated, many subsets of neurons in the vertebrate brain possess a sulfated proteoglycan surface coat which reacts to cationic iron colloid and aldehyde fuchsin. The present study demonstrated that this surface coat is supravitally stained with Ehrlich's methylene blue, and doubly with this blue and aldehyde fuchsin, a finding suggesting its being identical to Cajal's superficial reticulum (red superficial) and to Golgi's reticular coating (revetement reticulare). The perineuronal surface coat was further stained with Gömöri's ammoniacal silver, and doubly with this silver and cationic iron colloid. These neurons with such a proteoglycan surface coat usually expressed cell surface glycoproteins which were labeled with lectin Wisteria floribunda agglutinin. Hyaluronidase digestion did not interfere with this lectin labeling of the glycoproteins, methylene blue and Gömöri's ammoniacal silver staining of the surface coat, while it erased the cationic iron colloid and aldehyde fuchsin staining of the surface coat. These findings suggest that the perineuronal proteoglycan surface coat is associated with some additional molecules which are resistant to hyaluronidase digestion and stainable with methylene blue and Gömöri's ammoniacal silver. The possibility is suggested that these molecules might represent "ligand proteoglycans" connecting the perineuronal proteoglycans and cell surface glycoproteins.

The brain extracellular matrix (ECM) has attracted growing interest due to its highly regulated spatiotemporal expression during development and maturation of central nervous system. The present study deals with the post‐natal appearance and transformation into adult distribution patterns of the ECM components related to proteoglycans (PGs) and glycoproteins (GPs) in the retrosplenial cortex (RSC) of albino rats at birth (P0), 1 week (P1), P2, P3, P4, P5, P6, P7 and P8. The differentiating PGs and GPs components of the ECM were shown to make their appearance as early as 1–2 weeks post‐natally. At this developmental stage, these components of the ECM appeared in association with some neurons and glia cells or diffusely localized at the neutrophill. Interestingly, Golgi complexes of labelled neurons were usually stained with lectin VVA or WFA, and this labelling dramatically disappeared on reaching P4. During P2–3, the pericoated neuronal cells underwent a progressive increment in number, and presented an inside‐out pattern of migration and differentiation (toward the V‐II cortical layers). On reaching P4, most of the coated neurons appeared distributed into the cortical layer IV and II. At a later stage (P5–8), the overall density and intensity of labelled neurons progressively increased and apparently reached the adult stage of development. They also displayed the usual differential labelling characteristics, after using the cationic iron colloid/lectin staining, for the first time at this juncture. The present findings indicated that the perineuronal ECM components are significantly correlated with age and suggest a possible developmental or biological significance including promotion of migration, as well as functional maturation of the retrosplenial neurons.