Naringenin alleviates myocardial ischemia reperfusion injury by enhancing the myocardial miR-126-PI3K/AKT axis in streptozotocin-induced diabetic rats.

Ischemic heart disease (IHD) is a leading cause of death in patients with type 1 diabetes. The key to treating IHD is to restore blood supply to the ischemic myocardium, which inevitably causes myocardial ischemia reperfusion (MI/R) injury. Although naringenin (Nar) prevents MI/R injury, the role of Nar in diabetic MI/R (D-MI/R) injury remains to be elucidated. The PI3K/AKT signaling pathway and microRNA (miR)-126 have previously been shown to serve anti-MI/R injury roles. The present study aimed to investigate the protection of Nar against D-MI/R injury and the role of the miR-126-PI3K/AKT axis. Diabetic rats were treated distilled water or Nar (25 or 50 mg/kg, orally) for 30 days and then exposed to MI/R. The present results revealed that Nar alleviated MI/R injury in streptozotocin (STZ)-induced diabetic rats, as shown below: the reduction myocardial enzymes levels was measured using spectrophotometry, the increase of cardiac viability was detected by MTT assay, the inhibition of myocardial oxidative stress was measured using spectrophotometry and the enhancement of cardiac function were recorded using a hemodynamic monitoring system. Furthermore, Nar upregulated the myocardial miR-126-PI3K/AKT axis in D-MI/R rats. These results indicated that Nar alleviated MI/R injury through upregulating the myocardial miR-126-PI3K/AKT axis in STZ-induced diabetic rats. The current findings revealed that Nar, as an effective agent against D-MI/R injury, may provide an effective approach in the management of diabetic IHD.

[Effects of tannins in Galla Chinensis on pharmacokinetics of rifampicin in vivo and in vitro].

This study was aimed to explore the effects of tannins in Galla Chinensis on rifampicin in vivo. In the experiment in vitro, UV spectrophotometry and high performance liquid chromatography (HPLC) were used to investigate the solubility of rifampin in pH 1.3, 6.8, artificial gastric juice environment and artificial intestinal fluid environment as well as the effects of tannins on solubility of rifampin in the above conditions. In the experiment in vivo, the process of rifampicin was studied after intragastric administration of rifampicin and rifampicin+ tannins in Galla Chinensis, and then the pharmacokinetic parameters were calculated. The results showed that rifampicin was constantly precipitated in the artificial gastric juice environment over time, and nearly 85% of the rifampicin was precipitated after 6 hours; it showed a good solubility in the artificial intestinal juice environment. After adding the said tannins, the concentration of rifampicin was decreased significantly in both environments, and the concentration of rifampicin in artificial intestinal juice remained relatively stable, while that in artificial gastric juice remained the original downward trend. The pharmacokinetic parameters displayed that as compared with rifampicin alone, AUC0-t and Cmax were decreased significantly, MRT0-t slowed down significantly, Tmax doubled to 7.0 h and the bioavailability was only 31.65% in rifampicin + tannins in Galla Chinensis group. The experiment indicated rifampicin had a poor solubility in acidic environment and the decrease of bioavailability of rifampicin when in combination with tannin was mainly due to the reduction of rifampicin solubility in intestinal tract by complexation of rifampicin with tannin, thus affecting its absorption in intestinal tract. Therefore, rifampicin and the Chinese herbal medicines or Chinese patent medicines rich in tannin should not be taken simultaneously.