Histological and Immuno-histochemical Study of the Cytotoxic Effects of Gold Nanoparticles on the Palate of Albino Rats

Aim: The aim of the present work was to study the possible cytotoxic effect of gold nanoparticles on the palate of albino rats using routine H&E stain, Masson’ trichrome and immuno-histochemical detection of any possible changes in NF-κB (nuclear factor kappa).
Materials and methods: Forty-six adult male albino rats with an average of 150-180 gram body weight were used in this investigation. They were housed in rat cages, (five rats per cage), and labeled with numerical numbers and kept in well ventilated animal house at the faculty of dentistry, Suez Canal University, at temperature 27-30°C, 12 hours natural light and 12 hours darkness. The animals were fed with dry pellet and allowed drinking water adlibitum. Animals were divided randomly into three groups as follows: Group 1: consisted of 16 rats that received a daily intraperitoneal injection of AuNP solvent (0.5 ml deionized water) for 21 days and served as controls. Half the animals of the control group (sub-group 1.1) were euthanized after 21 days, while the other half (sub-group 1.2) were left untreated for one month, then euthanized.
Group 2: consisted of 15 rats that received 10mg/kg body weight /day of AuNPs solution dissolved in 0.5 ml deionized water with particle size around 30 nm intraperitoneal for 21 days.
Group 3: consisted of 15 rats, they were treated as group 2 for 21 days and then left for one month as a recovery period.
The experiment lasted for 21 days for group 2 then the rats were euthanized by cervical dislocation. While the rats of group 3 were euthanized after one month for recovery. The palate of all animals were dissected out, fixed in 10% neutral buffered formalin, processed and embedded in paraffin. Four to five microns thick sections were cut to be stained with; hematoxylin and eosin for histological examination, Masson’s trichrome stains for collagen evaluation and immune-histochemical localization of NF-κB (nuclear factor kappa) for detection of any possible cellular changes.
Results: The histological and immune-histochemical results revealed atrophy and degenerative changes in the palatal tissues associated with increased expression of nuclear factor kappa. A recovery period of one month resulted in regeneration and improvement in the histological structure and function of the tissues.