Effect of L-Carnitine Supplementation on Apelin and Apelin Receptor (Apj) Expression in Cardiac Muscle of Obese Diabetic Rats

Objective

L-carnitine (LC) has been shown to protect cardiac metabolism in diabetes patients with cardiovascular diseases (CVDs). Apelin, a newly discovered adipocytokines, is an important regulator of cardiac muscle function; however, the role of the level of expression of Apelin axis in improvement of cardiac function by LC in diabetic patients, is not clear. In the present study, obese insulin-resistant rats were used to determine the effect of LC, when given orally with a high-calorie diet, on Apelin and Apelin receptor (Apj) expression in cardiac muscle.

Materials and Methods

In this experimental study, rats were fed with high-fat/high-carbohydrate diet for five weeks and subsequently were injected with streptozotocin 30 mg/kg for induction of obesity and insulin resistance. After confirming the induction of diabetes (serum glucose above 7.5 mmol/L), the animals received LC 300 mg/kg in drinking water for 28 days. On days 0, 14 and 28 after treatment, cardiac Apelin and Apj gene expression was evaluated by real time polymerase chain reaction (PCR) analysis. Serum levels of insulin, Apelin, glucose, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and the homeostasis model assessment of insulin resistance (HOMA-IR) were also measured using commercial kits.

Results

Cardiac Apelin and Apj expression and serum Apelin were increased in obese rats, while LC supplementation decreased the serum levels of Apelin and down-regulated Apelin and Apj expression in cardiac muscle. These changes were associated with reduced insulin resistance markers and serum inflammatory factors and improved lipid profile.

Conclusion

We concluded that LC supplementation could attenuate the over-expression of Apelin axis in heart of diabetic rats, a novel mechanism by which LC improves cardiovascular complications in diabetic patients.

Gastroscopic Study of Meloxicam, Tramadol, and Their Combined Administration on the Development of Gastric Injuries in Dogs

Opioid and non-steroid anti-inflammatory drugs (NSAIDs) are commonly used to manage post-operative pain that may be chronically extended. Although NSAIDs have been approved for their analgesic effects in canine, they are mostly known to be associated with side effects, particularly gastric ulcers. In the present study, we evaluated short-term co-administration of meloxicam and tramadol to see if this could induce more gastric ulcers than that observed when using these drugs individually. Twenty adult mixed domestic dogs weighing 10 to 20 kg of both sexes, were randomly assigned to four groups of five dogs. In the control group, placebo was administered orally (twice a day), whereas the test groups received tramadol (per OS) twice a day, meloxicam (per OS) daily, and a combination of tramadol (twice a day) and meloxicam (daily) for ten days, respectively. The animals were evaluated for gastric injuries on days 0, 6, 11, 16 and 21 by endoscopy under general anesthesia. Clinical signs of all animals including fecal consistency, appetite, mental and hydration statuses, tempreture, heart rate and respiratory rate were evaluated daily. Based on our results, there was no significant difference between the experimental and control groups. In conclusion, our study demonstrated that a 10-day oral coadministration of tramadol and meloxicam had no deleterious effects on general health status and gastric mucosa in dogs.