Background Acetaminophen (APAP) induced hepatotoxicity is a clinically important problem. Up to now, interventive therapy with n-acetylcysteine (NAC) has been considered as a gold-standard treatment for APAP overdose. However, no study has focused on the efficacy of these drugs’ concurrent administration on probable enhancing therapeutic outcomes. Thus, this study was aimed to investigate the analgesic effect of co-administration of NAC and acetaminophen in male rats. The NAC-APAP drug formulation may demonstrate the stranger antinociceptive effect. Methods Forty-eight male Sprague-Dawley rats (12–14 weeks) randomly divided into six equal groups; control, APAP (received 300 mg/kg APAP), NAC (received 600 mg/kg NAC) and APAP+ NAC groups that received simultaneously 300 mg/kg APAP with 200–600 mg/kg NAC (AN200, AN400, AN600). All administrations were done orally for once. The antinociceptive effect was recorded by measurement of latency period on a hot plate in 30, 60, and 90 min after administrations. Results The results showed that NAC’s concurrent administration with APAP, dose-dependently increased APAP analgesic effects (p< 0.0001). Moreover, NAC treatment exhibited an antinociceptive effect in 60 and 90 min, per se. The treatments had no adverse effect on liver enzymes and oxidative stress. Conclusion Co-administration of NAC with APAP can improve the antinociceptive effect of APAP. It is suggested that this compound can enhance analgesic effects of APAP and eventually lead to a reduction in acetaminophen dose. Further studies are needed to evaluate the molecular mechanism of this hyper analgesic effect.

Introduction. Obesity and insulin resistance are associated with alterations in nitric oxide level and insulin secretion. Previous studies demonstrated that cinnamaldehyde (CNMA) improved islet insulin secretion and restored nitric oxide (NO) level, but its underlying mechanisms have not been investigated. This study aimed to investigate the effect of CNMA on inducible nitric oxide synthase (iNOS) activity and NO-induced islet insulin secretion in high-fat-diet (HFD) treated rats. Materials and Methods. Forty male Wistar rats (12 weeks old) were randomly divided into four equal groups, namely, control, CNMA, HFD, and HFD + CNMA. Control and CNMA groups were treated with standard laboratory animals’ diet, while HFD and HDF + CNMA groups were fed with an HFD diet enriched with 25% W / W tail fat for 16 weeks. CNMA was administrated orally (20 mg/kg body weight, daily) during the study period. Islet insulin secretion and the inducible NOS activity in the presence or absence of L-NAME (NO synthase inhibitor, 5 mmol/L) were evaluated. Results. L-NAME-suppressed insulin secretion in control, HFD, and HFD + CNMA groups; however, in the CNMA group, it could not exhibit such effect ( P < 0.01 ). Islets of HFD-treated animals showed significantly higher iNOS activity than controls. CNMA treatment significantly suppressed iNOS activities in CNMA and HFD + CNMA groups compared with control and HFD, respectively. Conclusion. These results suggest that the beneficial effect of CNMA on insulin secretion might be due to its inhibitory effect on iNOS activity.

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Introduction: Aging undoubtedly is associated with organ function failure and affects medical/surgical treatments. Free radicals are considered as one of the most common causes of senescence. Liver damage frequently occurs by advance age. Cinnamon (Cinnamomum zeylanicum) is one of the well-known spices in the world tend its antioxidant and hepatoprotective effects have been approved. This study aimed to evaluate the effect of cinnamon consumption on the recovery of partial hepatectomy. Methods and materials: In this experimental study, thirty-two male Sprague-Dawley rats (57 weeks) randomly divided into two equal groups; control (normal diet) and cinnamon (received diet with 1% cinnamon by weight) for 45 weeks. Then, partial hepatectomy (30% of total liver weight) was performed. (Blood collection and weighting were performed prior to hepatectomy and on the 2nd, 10th, and 28th days after the operation. The concentrations of nitric oxide metabolites (NOx), malondialdehyde (MDA), insulin, and glucose were assayed in serum. Results: The results showed that cinnamon consumption prevented postoperative weight loss. The cinnamon was significantly lowered serum MDA concentration 48 hours after hepatectomy as well as it significantly decreased weight loss due to partial hepatectomy on 2nd day after surgery. Change in serum NOx (% of no surgery animals) was dramatically increased following cinnamon consumption on the 2nd and 28th days after surgery. However, cinnamon did not affect serum glucose and insulin concentration. Conclusion: cinnamon improved postoperative outcomes after hepatic resection in rats by attenuation oxidative stress as well as nitric oxide content. It might be considered as a useful dietary recommendation for elderly patients with hepatic resection.