The purpose of this study was to illustrate the effects of zinc oxide nanoparticles (ZnO-NPs) administration on bone turnover and bone resorbing agents in rats and how L-arginine (L-arg) or vitamin E (vit E) co-administrations might affect them. Fasting rats were randomly divided into four groups (n = 10): G1-normal healthy animals; G2-ZnO-NPs-exposed rats (600 mg/kg1/day); G3-ZnO-NPs-exposed rats co-administrated L-arg (200 mg/kg1/day); G4-ZnO-NPs-exposed rats co-administrated vit E (200 mg/kg1/day). The ingredients were orally administered daily. The body weight and food consumption of rats were recorded during the administration period and the experiment continued for three consecutive weeks. The results demonstrated that ZnO-NPs administration induced bone loss in rats as manifested by reduced activity of bone alkaline phosphatase (B-ALP) and increased level of C-terminal peptide type I collagen (CTx). The increase of inflammatory markers, tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) by ZnO-NPs suggests that deleterious effects of ZnO-NPs on bone turnover were, in part, due to inflammation. Confirming to this suggestion, both L-arg and vit E reduced TNF-α and IL-6 levels and consequently decreased bone resorption as indicated by reduced serum CTx level. This study proved that ZnO-NPs can induce bone turnover, which may be reduced by L-arg or vit.E co-administration, partly by anti-inflammatory mechanism.

The objective of this work was to evaluate the beneficial effect of α-lipoic acid (ALA) and L-carnitine (CAR) on insulin sensitivity and anti-inflammatory markers in animal model of metabolic syndrome (MS), high fructose (HF)-fed rats. Forty male rats were randomly divided into four groups (n = 10). Group 1(control rats, G1), animals were allowed to drink 0.2% gum acacia (GA, p.o) and were fed a modified diet containing 65% cornstarch. The remaining rats were induced MS by feeding the same diet + free access to 10% fructose (w/v) in 0.2% GA (HF, MS) for 4 weeks. After 4 weeks of HF feeding, the rats were further divided into three subgroups; G2: HF (MS) in 0.2% GA, G3: HF (MS)+CAR (200 mg/kg/day) in 0.2% GA and G4: HF (MS)+ALA (200 mg/kg/day) in 0.2% GA, respectively. All ingredients were administered orally by guava daily for four weeks. A significant increase in serum glucose, insulin and Homeostasis Model Assessment-Insulin Resistance (HOMA-IR) levels was observed after four weeks of HF feeding compared to control rats. Administration of ALA and CAR reversed the increase of the mentioned parameters. In HF rats, the increase of serum triglycerides (TG), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-C) levels were significantly lowered, while the reduction of the serum high-density lipoprotein cholesterol (HDL-C) was alleviated after administration of CAR and ALA. The reduction of the serum adiponectin level was significantly increased after administration of CAR and ALA. These data suggested that CAR and/or ALA had a beneficial role in the prevention of MS associated with development of type 2 diabetes.