The Effect of Pentoxifylline on Passive Avoidance Learning and Expression of Tumor Necrosis Factor-Alpha and Caspase-3 in the Rat Hippocampus Following Lipopolysaccharide-Induced Inflammation

Effects of Pentoxifylline on Serum Markers of Diabetic Nephropathy in Type 2 Diabetes

OBJECTIVE

To investigate the effects of pentoxifylline (PTX) in combination with losartan compared to the high dose of losartan alone on serum markers of diabetic nephropathy such as HSP70, copeptin, CRP, and TNFα in patients with type 2 diabetes and nephropathy.

METHODS

A single-center, randomized, double-blind, open-label clinical trial was conducted. Sixty-two patients were eligible and allocated to "PTX + losartan" and "high-dose losartan" arms of the trial using software for random number generation. The first arm received 400 mg PTX two times a day (BD) plus 50 mg losartan daily, while the second arm received 50 mg losartan two times a day (BD) for 12 weeks. Comparison of the biomarkers' levels before and after treatment was done using paired sample t test variance. ANCOVA was applied to evaluate the comparative efficacy of the two interventions. The effect size was calculated and reported for each biomarker.

RESULTS

Urine albumin excretion (UAE), hs-CRP, and HbA1c significantly decreased in both trial arms compared to the baseline measures. Copeptin and TNFα showed significant differences (after vs before) only in the losartan group (p = 0.017 and p = 0.043, respectively). The losartan arm was more successful in reducing TNFα, copeptin, HSP70, systolic blood pressure (SBP), and diastolic blood pressure (DBP) values (p = 0.045, effect size = 7.3%; p = 0.018, effect size 10.1%; p = 0.046, effect size 4.7%, p = 0.001, effect size 23%; p = 0.012, effect size 10.2%, respectively) and the PTX arm was associated with a superior reduction of UAE and hs-CRP levels (p = 0.018, effect size 9.1%; p = 0.028, effect size 9.2%, respectively).

CONCLUSION

Add-on PTX to losartan may have more effective anti-inflammatory and anti-albuminuric roles and therefore may be more applicable in the management of diabetic nephropathy compared with high-dose losartan alone.

TRAIL REGISTRATION

Trial number IRCT 20121104011356N10.

Pentoxifylline-induced protein expression change in RAW 264.7 cells as determined by immunoprecipitation-based high performance liquid chromatography

Although pentoxifylline (PTX) was identified as a competitive non-selective phosphodiesterase inhibitor, its pharmacological effect has not been clearly elucidated. The present study explored the effect of low dose 10 μg/mL PTX (therapeutic dose) compared to high dose 300 μg/mL PTX (experimental dose) in RAW 264.7 cells through immunoprecipitation-based high performance liquid chromatography (IP-HPLC), immunohistochemistry, and western blot. 10 μg/mL PTX increased the expression of proliferation (Ki-67, PCNA, cyclin D2, cdc25A), epigenetic modification (KDM4D, PCAF, HMGB1), protein translation (DOHH, DHPS, eIF5A1), RAS signaling (KRAS, pAKT1/2/3, PI3K), NFkB signaling (NFkB, GADD45, p38), protection (HSP70, SOD1, GSTO1/2), survival (pAKT1/2/3, SP1, sirtuin 6), neuromuscular differentiation (NSEγ, myosin-1a, desmin), osteoblastic differentiation (BMP2, RUNX2, osterix), acute inflammation (TNFα, IL-1, CXCR4), innate immunity (β-defensin 1, lactoferrin, TLR-3, -4), cell-mediated immunity (CD4, CD8, CD80), while decreased the expression of ER stress (eIF2α, eIF2AK3, ATF6α), fibrosis (FGF2, CTGF, collagen 3A1), and chronic inflammation (CD68, MMP-2, -3, COX2) versus the untreated controls. The activation of proliferation by 10 μg/mL PTX was also supported by the increase of cMyc-MAX heterodimer and β-catenin-TCF1 complex in double IP-HPLC. 10 μg/mL PTX enhanced FAS-mediated apoptosis but diminished p53-mediated apoptosis, and downregulated many angiogenesis proteins (angiogenin, VEGF-A, and FLT4), but upregulated HIF1α, VEGFR2, and CMG2 reactively. Whereas, 300 μg/mL PTX consistently decreased proliferation, epigenetic modification, RAS and NFkB signaling, neuromuscular and osteoblastic differentiation, but increased apoptosis, ER stress, and fibrosis compared to 10 μg/mL PTX. These data suggest PTX has different biological effect on RWA 264.7 cells depending on the concentration of 10 μg/mL and 300 μg/mL PTX. The low dose 10 μg/mL PTX enhanced RAS/NFkB signaling, proliferation, differentiation, and inflammation, particularly, it stimulated neuromuscular and osteoblastic differentiation, innate immunity, and cell-mediated immunity, but attenuated ER stress, fibrosis, angiogenesis, and chronic inflammation, while the high dose 300 μg/mL PTX was found to alleviate the 10 μg/mL PTX-induced biological effects, resulted in the suppression of RAS/NFkB signaling, proliferation, neuromuscular and osteoblastic differentiation, and inflammation.

Effect of Pentoxifylline on Apoptotic-Related Gene Expression Profile, Learning and Memory Impairment Induced by Systemic Lipopolysaccharide Administration in the Rat Hippocampus

Background:

Inflammation is one of the effective factors, in the development of functional disorders of the nervous system. Pentoxifylline (PTX) has an inhibitory effect on inflammatory factors. Therefore the aim of this study was to evaluate the effect of PTX on learning, memory and expression of genes, involved in neuronal survival in the rat hippocampus, following systemic lipopolysaccharide (LPS) injection.

Methods:

Male rats were randomly divided into 5 groups of control, LPS and LPS + PTX, receiving doses of 10, 25 and 50 mg/kg of PTX, respectively. In LPS groups, LPS was injected (5 mg/kg; intraperitoneal), and after one week, rats received intraperitoneal PTX for 14 days, in the treatment groups. Learning and memory were evaluated by object location task (OLT) and novel object recognition (NOR). Then, the hippocampus was dissected in order to measure the expression of the associated genes.

Results:

The results showed that peripheral LPS injection caused significant damage (P < 0.01) to learning and memory with respect to controls, but PTX with doses of 10 and 50 mg/kg prevented these impairments. Results from reverse transcription polymerase chain reaction (RT-PCR) showed that LPS significantly increased the expression of Bax and TNF- α with respect to controls. PTX in the LPS + PTX group significantly increased the expression of Bcl-2, BAD and Caspase-3.

Conclusions:

Other than the increased Bcl-2 expression, PTX had no significant effect on the expression of other genes, therefore further studies are needed to find out how PTX improves the learning and memory impairments, following the peripheral inflammation.

Intravoxel Incoherent Motion Imaging Study of Madecassoside in Improving Lipopolysaccharide-Induced Cognitive Impairment in Rats

BACKGROUND

Central nervous system inflammation is associated with neurodegenerative diseases and is thought to play a part in the pathophysiological cascade leading to cognitive impairment. Madecassoside (MA) has shown potential for the treatment of neuroinflammation. Lipopolysaccharide (LPS) can be used to establish an animal model of cognitive dysfunction induced by neuroinflammation. Intravoxel incoherent motion (IVIM) may potentially provide diffusion and perfusion data.

PURPOSE

To investigate the effect of MA on neurocognitive impairment induced by LPS in rats, and to explore the changes of brain microstructure and microcirculatory perfusion by IVIM imaging.

STUDY TYPE

Prospective.

POPULATION

Thirty-six male Sprague-Dawley rats were randomly divided into six groups (control group, sham operation group, LPS group, low-dose MA group, middle-dose MA group, and high-dose MA group) in a model of neurocognitive impairment induced by LPS (150 μg / 5 μL, 5 μL).

FIELD STRENGTH/SEQUENCE

IVIM-DWI sequence at 3.0T MRI; the scan time was 2 minutes and 17 seconds.

ASSESSMENT

The escape latency times of a Morris water maze test was used to evaluate the cognitive impairment rat model and the changes of learning ability of rats treated with different doses of MA (30 mg/kg, 60 mg/kg, 120 mg/kg). A GE postprocessing workstation (adw 4.5) was used to analyze the changes of each parameter (f value, D value, and D* value) in the IVIM data of each group.

STATISTICAL TESTS

All the data were analyzed by one-way and two-way analysis of variance (ANOVA).

RESULTS

The escape latency of the LPS group was significantly longer than the sham group (P = 0.05, 0.001, 0.006, and 0.042, respectively), and the high-dose group was significantly shorter than the LPS group on the sixth day (P = 0.034). Compared with the control group, the D values and f values of cerebral cortex and hippocampus were decreased significantly in the LPS group (P = 0.043 and 0.003; P = 0.029 and 0.016, respectively). With the increasing dose of MA, the D and f values of hippocampus and cortex increased, and there was a significant difference between the high-dose MA group and LPS group (D values: P = 0.038, 0.036; f values: P = 0.048, 0.039, respectively) DATA CONCLUSION: MA can improve the cognitive impairment induced by LPS by reducing neuroinflammation, and the changes of microcirculation and microperfusion in the brain tissue of these rats can be detected by IVIM imaging.

LEVEL OF EVIDENCE

1 Technical Efficacy Stage: 4 J. Magn. Reson. Imaging 2020;51:1836-1843.