Influence of Pinealectomy and Long-term Melatonin Administration on Inflammation and Oxidative Stress in Experimental Gouty Arthritis.

Gout is an inflammatory arthritis characterized by the deposition of monosodium urate (MSU) crystals in the joints or soft tissue. MSU crystals are potent inflammation inducers. Melatonin (MLT) is a powerful endogenous anti-inflammatory agent and effective in reducing cellular damage. In the present study, possible underlying mechanisms associated with anti-inflammatory and antioxidative effects were investigated in rats with gouty arthritis and melatonin deprivation treated with MLT. Fifty-six rats were divided into seven groups: control, sham control, pinealectomy (PNX), MSU (on the 30th day, single-dose 20 mg/ml, intraperitoneal), MSU + MLT (10 mg/kg/day for 30 days, intraperitoneal), MSU + PINX and MSU + PINX + MLT. PNX procedure was performed on the first day of the study. As compared to the controls, the results showed that MSU administration caused significant increases in oxidative stress parameters (malondialdehyde and total oxidant status). Besides, significant decreases in antioxidant defense systems (glutathione, superoxide dismutase and total antioxidant status) were observed. A statistically significant increase was found in the mean histopathological damage score in the groups that received MSU injection. It was found that histopathological changes were significantly reduced in the MSU + MLT group given MLT. In our study, it was determined that many histopathological changes, as well as swelling and temperature increase in the joint, which are markers of inflammation, were significantly reduced with MLT supplementation. These results suggest that melatonin ameliorates MSU-induced gout in the rat through inhibition of oxidative stress and proinflammatory cytokine production.

Effects of pinealectomy and crocin treatment on rats with isoproterenol-induced myocardial infarction.

The present study aimed to analyze the effects of pinealectomy and crocin treatment in isoproterenol-induced myocardial damage. Seventy rats were divided into seven groups: control, sham control, pinealectomy (PNX), isoproterenol (ISO; 85 mg/kg on the 29th and 30th days of the experiment, subcutaneous injection), PNX + ISO, PNX + crocin (50 mg/kg/day for 30 days, intragastric administration), and PNX + ISO + crocin. PNX procedure was performed on the first day of the study. A significant increase was observed in serum cardiac damage markers (CK-MB, Troponin I) after ISO administration. ISO administration led to a significant increase in cardiac oxidative stress parameters, such as malondialdehyde (MDA) and total oxidant status (TOS), while it led to a decrease in antioxidant defense system parameters, such as reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and total antioxidant status (TAS) when compared to control groups. Elevated MDA and TOS levels were observed, while reduced SOD and CAT activities, and decreased GSH and TAS levels were observed in the group that underwent PNX and ISO administration when compared to the PNX group. Furthermore, in the PNX + ISO + Crocin group, SOD and CAT activities, and GSH and TAS levels ameliorated and MDA and TOS levels were reduced with the crocin treatment when compared to the PNX + ISO group. Also, marked increases were observed in serum cardiac markers, histopathological and immunohistochemical findings after the crocin treatment. All findings demonstrated that crocin could be employed as a cardioprotective agent due to its antioxidant, anti-inflammatory, and anti-apoptotic properties.