Increased myofibroblast contractile sensitivity in paraquat pretreated rat lung tissue

Animal models of Parkinson's disease: bridging the gap between disease hallmarks and research questions

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by motor and non-motor symptoms. More than 200 years after its first clinical description, PD remains a serious affliction that affects a growing proportion of the population. Prevailing treatments only alleviate symptoms; there is still neither a cure that targets the neurodegenerative processes nor therapies that modify the course of the disease. Over the past decades, several animal models have been developed to study PD. Although no model precisely recapitulates the pathology, they still provide valuable information that contributes to our understanding of the disease and the limitations of our treatment options. This review comprehensively summarizes the different animal models available for Parkinson's research, with a focus on those induced by drugs, neurotoxins, pesticides, genetic alterations, α-synuclein inoculation, and viral vector injections. We highlight their characteristics and ability to reproduce PD-like phenotypes. It is essential to realize that the strengths and weaknesses of each model and the induction technique at our disposal are determined by the research question being asked. Our review, therefore, seeks to better aid researchers by ensuring a concrete discernment of classical and novel animal models in PD research.

Novel and extensive aspects of paraquat-induced pulmonary fibrogenesis: comparative and time-course microarray analyses in fibrogenic and non-fibrogenic rats

Although paraquat (PQ) is widely known to induce pulmonary fibrosis, the molecular mechanisms are poorly understood. Therefore, to bring a new dimension to the elucidation of the mechanisms, we conducted microarray experiments to investigate the expression profiles of 1,090 genes in the lungs during the progressive phase of PQ-induced pulmonary fibrosis in rats. After several s.c. injections of PQ, rats were divided into a fibrogenic group and a non-fibrogenic group. Time-course gene expression analysis of the fibrogenic group showed altered gene regulation throughout the experimental period. The expression levels of many cell membrane channel, transporter, and receptor genes were substantially altered. These genes were classified into two categories: polyamine transporter- and electrolyte/fluid balance-related genes. Moreover, comparative analysis of the fibrogenic and the non-fibrogenic group revealed 36 genes with significantly different patterns of expression, including the pro-apoptotic gene Bad. This indicates that Bad is a key factor in apoptosis and that apoptosis provides a major turning point in PQ-induced pulmonary fibrosis. Notably, subtypes of transforming growth factor (TGF)-beta genes that are considered to play a pivotal role in fibrogenesis showed no differences in expression between the two groups, though TGF-beta3 was markedly induced in both groups. These results provide novel and extensive insights into the molecular mechanisms that lead to pulmonary fibrosis after exposure to PQ.

High blood pressure is one of the symptoms of paraquat-induced toxicity in rats

This study investigated whether paraquat (Pq)-induced lipidic peroxidation (LP) is accompanied by changes in blood pressure and heart rate (HR) in rats. Groups of adult male Wistar rats were studied 2 and 12 h after Pq (35 mg/kg, i.p.) administration. The LP was evaluated by monitoring thiobarbituric acid reactive substances (TBARS) in the kidneys, liver and lungs, and validated by including a group treated with an antioxidant, superoxide dismutase (CuZnSOD 50,000 IU/kg), in the study. The TBARS levels were significantly higher (p<0.05) in the kidneys of the rats studied 2 h after Pq than in their respective controls. Similarly, systolic and diastolic blood pressure (DBP) were higher (p<0.05), while HR was lower (p<0.05) than basal levels 2 and 12 h after Pq administration. In contrast, the group treated simultaneously with Pq and CuZnSOD exhibited lower levels of TBARS (p<0.05) in all studied organs compared to the control group, while the mean arterial pressure and HR did not differ from those seen in the control group. These findings indicate that acute Pq poisoning symptoms include high blood pressure.

The role of sodium cromolyn in treatment of paraquat-induced pulmonary fibrosis in rat

Paraquat is a non-selective herbicide which is widely used in agriculture. It has potential of producing pulmonary fibrosis. In this study the therapeutic effect of different doses of sodium cromolyn on the development of paraquat-induced pulmonary fibrosis was investigated. In order to produce lung fibrosis, rats were given single oral dose of paraquat (40 mg kg(-1)). Two groups of animals were nebulised with 6 or 8 mg day(-1) cromolyn (divided into two doses per day) 5 days prior and 2 weeks after paraquat treatment. Control animals were given equivalent volume of normal saline and treated with cromolyn similar to the test groups. Rats were killed at the end of treatment course and lung tissues were tested histologically and biochemically. Histological examination of paraquat-treated animals showed marked infiltration of inflammatory cells in the alveolar spaces, septal thickening and fibrosis. Lesions were evident in many places of sections. Sodium cromolyn could markedly reduce such damages in lung tissue. Lung weight, hydroxyproline and collagen content of lung tissues were elevated significantly (P < 0.05) in paraquat group compared with control group. In cromolyn-treated groups such factors were near to control value and were significantly lower than paraquat group (P < 0.05). Results of this study indicate that sodium cromolyn can decrease the fibrogenic effect of paraquat on lung. Such effect may be due to the stabilising of mast cells and inhibition of inflammatory mediators by sodium cromolyn.