Effects of calcium channel blockers on hyaluronidase-induced capillary vascular permeability

Protective effect of an L-type calcium channel blocker, amlodipine, on paracetamol-induced hepatotoxicity in rats

Paracetamol (P), one of the most popular and commonly used analgesic and antipyretic agents, causes hepatotoxicity in overdoses. Amlodipine (AML), an L-type calcium channel blocker, has been shown to have anti-inflammatory activity by reversing the effect of calcium in the inflammation pathogenesis. In this study, the hepatoprotective activity of AML on P-induced hepatotoxicity was evaluated. Thirty male albino Wistar rats were divided into five groups: (1) control, (2) 2 g/kg of P, (3) 2 g/kg of P + 5 mg/kg of AML, (4) 2 g/kg of P + 10 mg/kg of AML, and (5) 10 mg/kg of AML. Some liver enzymes, oxidative parameters, cytokine mRNA expressions, histopathology, and immunohistochemical studies were performed in liver and blood samples. The serum levels of alanine aminotransferase and aspartate aminotransferase and the mRNA expression of tumor necrosis factor-alpha (TNF-α) and transforming growth factor-beta in the liver tissues were significantly increased in the group treated with P. The superoxide dismutase and glutathione parameters decreased and malondialdehyde levels increased in the livers of the rats treated with P. All these parameters were increased with both doses of the AML similar to the control group. A histopathological examination of the liver showed that AML administration ameliorated the P-induced inflammatory liver damage. In immunohistochemical staining, the expression of TNF-α in the cytoplasm of the hepatocytes was increased in the P group but not in other treatment groups when compared to the control. In conclusion, AML treatment showed significant protective effects against P-induced hepatotoxicity by increasing the activity of antioxidants and reducing inflammatory cytokines.

The effects of amlodipine on the biochemical and histopathological changes in the rabbit ileum subjected to ischemia-reperfusion

OBJECTIVE

The aim of this study was to determine the potential, protective effects of amlodipine in an experimental, ischemia-reperfusion (I/R) model in the rabbit small intestine.

MATERIALS AND METHODS

The rabbits were divided into four groups: sham-operated, amlodipine (10 mg/kg) + sham-operated, I/R, and I/R + amlodipine (10 mg/kg) groups. An intestinal I/R model was applied to the rabbits. The superior mesenteric artery was occluded for 1 h with an atraumatic vascular clamp and then was reperfused for 2 h. Animals in the amlodipine and I/R + amlodipine groups received the amlodipine by oral gavage. At the end of the 2-h-reperfusion period, the animals were sacrificed.

RESULTS

Pretreatment with amlodipine significantly increased SOD activity and GSH levels to values close to those found in the serum from the I/R group. Rabbits in the I/R group showed high levels of serum MDA. Amlodipine pretreatment significantly reduced the serum MDA levels compared to the I/R group, although the MDA levels in the I/R + amlodipine group were still higher than in the sham-operated group. The I/R damage was ameliorated by amlodipine pretreatment, as evidenced by histopathological analysis.

CONCLUSION

The present study is the first to report an attenuation of I/R-induced intestinal injury by the systemic administration of amlodipine.

Dynamic, size-selective effects of protamine sulfate and hyaluronidase on the rat glomerular filtration barrier in vivo

The proteinuric actions of protamine sulfate (PS) have classically been, at least partly, attributed to alterations of the negatively charged glomerular endothelial glycocalyx. To investigate whether the charge-selective properties of the glomerular filtration barrier (GFB) would be altered by PS, we assessed the glomerular sieving of conventional, uncharged, polydispersed Ficoll (n-Ficoll) compared with charge modified, conformationally intact, anionic (carboxymethylated) Ficoll (a-Ficoll) before and after systemic infusions of PS in rats. For comparison, we also investigated the impact of hyaluronidase (hyase), which partially degrades the glycocalyx, on GFB permeability. In anaesthetized Wistar rats, blood access was achieved, and the left ureter was cannulated for urine collection. Rats were infused with either n-Ficoll or a-Ficoll before and during systemic infusions with either PS or hyase. Plasma and urine samples were taken repeatedly and analyzed by high-performance size exclusion chromatography to assess glomerular sieving coefficients (θ) for Ficoll (radius 10-80 Å). The GFB showed a significant glomerular charge selectivity for Ficoll molecules of radius 20-35 Å. PS and hyase infusions reversibly increased θ for large Ficoll molecules (Ficoll molecules of radius 50-80 Å). Thus, for PS, θ for a-Ficoll molecules of radius 70 Å increased from 2.47 × 10(-5) ± 1.1(-5) to 7.25 × 10(-5) ± 1.1(-5) (P < 0.05) at 15 min. For hyase, changes in a-Ficoll molecules of radius 50-80 Å were, however, not statistically significant. Neither PS nor hyase had any effect on θ for n-Ficoll molecules of radius 20-45 Å or a-Ficoll molecules of radius 20-45 Å. It is concluded that systemically administered PS and hyase in moderate doses dynamically decreased the size selectivity of the rat GFB without affecting its charge selective properties.

Anti-inflammatoryactivity of calciumchannel blocker lercanidipine hydrochloride

OBJECTIVE

To evaluate the anti-inflammatory effect of the third-generation CCB, lercanidipine.

MATERIALS AND METHODS

The ability of lercanidipine to reduce inflammation in carrageenan-induced paw edema in rats was evaluated, using different doses and its anti-inflammatory effect was compared with that of diclofenac sodium. Mast cell degranulation effect of lercanidipine was also carried out.

RESULTS

Lercanidipine produced a significant reduction in the inflammatory paw edema at all doses and at all intervals (P < 0.001). The percentage of reduction in edema was found to be proportionate to the doses of lercanidipine. Lercanidipine also significantly reduced the percentage of propranolol-induced mast cell degranulation.

CONCLUSIONS

It was found that lercanidipine exerts a positive anti-inflammatory effect in a dose-dependent manner and was superior to diclofenac sodium.