Changes Experienced by Low-Concentration Lipid Bicelles as a Function of Temperature

Differential scanning calorimetry (DSC) of dipalmitoyl phosphatidylcholine (DPPC), dihexanoyl phosphatidylcholine, and dipalmitoyl phosphatidylglycerol bicelles reveals two endothermic peaks. Based on analysis of small angle neutron scattering and small angle X-ray scattering data, the two DSC peaks are associated with the melting of DPPC and a change in bicellar morphology─namely, either bicelle-to-spherical vesicle or oblate-to-spherical vesicle. The reversibility of the two structural transformations was examined by DSC and found to be consistent with the corresponding small angle scattering data. However, the peak that is not associated with the melting of DPPC does not correspond to any structural transformation for bicelles containing distearoyl phosphatidylethanolamine conjugated with polyethylene glycol. Based on complementary experimental data, we conclude that membrane flexibility, lipid miscibility, and differential solubility between the long- and short-chain lipids in water are important parameters controlling the reversibility of morphologies experienced by the bicelles.

Renoprotective effect of red grape (Vitis vinifera L.) juice and dark raisins against hypercholesterolaemia-induced tubular renal affection in albino rats

BACKGROUND

Red grape juice (RGJ) and dark raisins (DR) are rich in polyphenols and antioxidants. This study aimed to assess the efficacy of RGJ and DR in protec- ting the renal tubules against hypercholesteraemic-induced pathological changes.

MATERIALS AND METHODS

Forty albino rats divided into four groups (n = 10) were utilised in this study. They included the control, high cholesterol diet (HCD)-fed, HCD+RGJ-fed, and HCD+DR-fed groups. Body weight gain, food and water in- take, blood and insulin levels, lipid profile and kidney functions were assessed at the start of the experiment and after 12 weeks. The right kidney was dissected out and processed for both light and electron microscopic examination. Desmin and cytokeratin antibodies were utilised as histologic markers to assess the integrity of the proximal (PTs) and distal tubules (DTs) of the kidney.

RESULTS

Administration of HCD resulted in hypercholesterolaemia in rats as evi- denced by the lipid profile. The PTs of hypercholesteraemic rats appeared dilated with hyaline casts and mitochondria in most of the tubular cells were affected. Immunohistochemical assessment revealed affection of both PTs and DTs. Both RGJ and DR, when administered along with the HCD for 12 weeks, improved the lipid profile, kidney functions as well as the histologic and cellular changes-induced by hypercholesterolaemia in the rats. The effect of raisins was superior to RGJ which might be due to its high contents of fibres and proteins.

CONCLUSIONS

This study highlighted the importance of supplementation of red grape and raisins in protection against the harmful effects induced by deposition of fat on the renal tubules' structure and function.