Alpha-1 Acid Glycoprotein as a Biomarker for Subclinical Illness and Altered Drug Binding in Rats

Alpha-1 acid glycoprotein (AGP) is a significant drug binding acute phase protein that is present in rats. AGP levels are known to increase during tissue injury, cancer and infection. Accordingly, when determining effective drug ranges and toxicity limits, consideration of drug binding to AGP is essential. However, AGP levels have not been well established during subclinical infections. The goal of this study was to establish a subclinical infection model in rats using AGP as a biomarker. This information could enhance health surveillance, aid in outlier identification, and provide more informed characterization of drug candidates. An initial study (n = 57) was conducted to evaluate AGP in response to various concentrations of Staphylococcus aureus (S. aureus) in Sprague-Dawley rats with or without implants of catheter material. A model validation study (n = 16) was then conducted using propranolol. Rats received vehicle control or S. aureus and when indicated, received oral propranolol (10 mg/kg). Health assessment and blood collection for measurement of plasma AGP or propranolol were performed over time (days). A dose response study showed that plasma AGP was elevated on day 2 in rats inoculated with S. aureus at 10⁶, 10⁷ or, 10⁸ CFU regardless of implant status. Furthermore, AGP levels remained elevated on day 4 in rats inoculated with 10⁷ or 10⁸ CFUs of S. aureus. In contrast, significant increases in AGP were not detected in rats treated with vehicle or 10³ CFU S. aureus. In the validation study, robust elevations in plasma AGP were detected on days 2 and 4 in S. aureus infected rats with or without propranolol. The AUC levels for propranolol on days 2 and 4 were 493 ± 44 h × ng/mL and 334 ± 54 h × ng/mL, respectively), whereas in noninfected rats that received only propranolol, levels were 38 ± 11 h × ng/mL and 76 ± 16. h × ng/mL, respectively. The high correlation between plasma propranolol and AGP demonstrated a direct impact of AGP on drug pharmacokinetics and pharmacodynamics. The results indicate that AGP is a reliable biomarker in this model of subclinical infection and should be considered for accurate data interpretation.

Ameliorative effects of N-acetyl cysteine on diclofenac-induced renal injury in male rats based on serum biochemical parameters, oxidative biomarkers, and histopathological study

Diclofenac (DIC) can cause nephrotoxicity in humans. In this study, we evaluated the protective effects of N-acetyl cysteine (NAC) on DIC-induced nephrotoxicity. Rats were assigned to four groups. Group 1 was control group; group 2 administrated with DIC only; group 3 administrated with DIC plus NAC and group 4 was treated with DIC and silymarin. Then, the oxidative biomarkers in serum and kidney were evaluated. In group 2, DIC caused a remarkable elevation (p < 0.05) in the levels of serum uric acid, TNF-α, creatinine, urea, GOT, and GPT, protein carbonyl, malondialdehyde (MDA), and renal TNF-α gene expression, relative to control group. In treated groups with NAC and silymarin, a noticeable reduction (p < 0.05) was seen in mentioned levels of biochemical parameters. NAC showed that it could reduce the abnormality of biochemical parameters and histopathological changes which is induced by DIC. PRACTICAL APPLICATIONS: N-acetyl cysteine (NAC) has a potential to ameliorate renal histopathological changes and improving renal activity of antioxidant enzymes in nephrotoxicity by diclofenac. Also, NAC has a potential to reduce inflammatory gene expression in the diclofenac-induced nephrotoxicity. Additionally, NAC can be considered as an antioxidant which reduces renal MDA and serum protein carbonyl due to nephrotoxicity by diclofenac.

Change in the Lipid Transport Capacity of the Liver and Blood during Reproduction in Rats

To support the high energetic demands of reproduction, female mammals display plasticity in many physiological processes, such as the lipid transport system. Lipids support the energy demands of females during reproduction, and energy and structural demands of the developing offspring via the placenta in utero or milk during the suckling period. We hypothesized that key proteins supporting lipid transport in reproductive females will increase during pregnancy and lactation, but drop to non-reproductive levels shortly after reproduction has ended. We compared the relative protein levels of liver-type cytosolic fatty acid transporter (L-FABP_c), plasma membrane fatty acid transporter (FABPpm), fatty acid translocase (FAT/CD36) in the liver, a key site of lipid storage and synthesis, and free fatty acid transporter albumin and triglyceride transporter [represented by apolipoprotein B (apoB)] levels in serum in reproductive Sprague-Dawley rats during late pregnancy, peak-lactation, and 1-week post-lactation as well as in non-reproductive rats. We found that all lipid transporter levels were greater in pregnant rats compared to non-reproductive rats. Lactating rats also showed higher levels of FAT/CD36 and FABPpm than non-reproductive rats. Moreover, all fat transporters also dropped back to non-reproductive levels during post-lactation except for FAT/CD36. These results indicate that fat uptake and transport capacities in liver cells are elevated during late gestation and lactation. Liver lipid secretion is up-regulated during gestation but not during lactation. These data supported the plasticity of lipid transport capacities in liver and blood during reproductive stages.