Critical analysis and systematization of rat pancreatectomy terminology

Hippocampal Microglia Activation Induced by Acute Pancreatic Injury in Rats

BACKGROUND

Acute pancreatitis is an inflammation of the pancreatic glandular parenchyma that causes injury with or without the destruction of pancreatic acini. Clinical and experimental evidence suggest that certain systemic proinflammatory mediators may be responsible for initiating the fundamental mechanisms involved in microglial reactivity. Here, we investigated the possible repercussions of acute pancreatitis (AP) on the production of inflammatory mediators in the brain parenchyma focusing on microglial activation in the hippocampus.

METHODS

The acute pancreatic injury in rats was induced by a pancreas ligation surgical procedure (PLSP) on the splenic lobe, which corresponds to approximately 10% of total mass of the pancreas. Blood samples were collected via intracardiac puncture for the measurement of serum amylase. After euthanasia, frozen or paraffin-embedded brains and pancreas were analyzed using qRT-PCR or immunohistochemistry, respectively.

RESULTS

Immunohistochemistry assays showed a large number of Iba1 and PU.1-positive cells in the CA1, CA3, and dentate gyrus (DG) regions of the hippocampus of the PLSP group. TNF-α mRNA expression was significantly higher in the brain from PLSP group. NLRP3 inflammasome expression was found to be significantly increased in the pancreas and brain of rats of the PLSP group. High levels of BNDF mRNA were found in the rat brain of PLSP group. In contrast, NGF mRNA levels were significantly higher in the control group versus PLSP group.

CONCLUSION

Our findings suggest that AP has the potential to induce morphological changes in microglia consistent with an activated phenotype.

Laparoscopic Pancreatectomy in Rats: The Development of an Experimental Model

INTRODUCTION

several pancreatectomy techniques in rats have been described and utilized for research concerning the pancreas endocrine and exocrine functions. However, we did not find a description of any kind of laparoscopic pancreatectomy in rats in the consulted databases. The objective of this study is to describe a laparoscopic splenic lobe pancreatectomy in rats.

METHODS

ten Wistars rats weighting more then 300 g were operated for standardizing the laparoscopic pancreatosplenectomy technique, aided by previous descriptions of laparoscopic splenectomy and open pancreatectomy in rats. Adjustments have been progressively adopted for technical refinement.

RESULTS

In five animals a low-cost rat laparoscopic set was used. In other five animals we used a standard laparoscopic set. Three rats died early due to different causes: transection of the gastroesophageal junction, hemorrhagic shock and inadvertent colonic injury. The postoperative period of the other seven rats was uneventful until the seventh postoperative day.

DISCUSSION

laparoscopic distal pancreatectomy and splenectomy in rats is feasible and safe, even with a low-cost set, in which the results were alike the standard laparoscopic set.

Rat pancreatectomy combined with isoprenaline or uninephrectomy as models of diabetic cardiomyopathy or nephropathy

Cardiovascular and renal complications are the predominant causes of morbidity and mortality amongst patients with diabetes. Development of novel treatments have been hampered by the lack of available animal models recapitulating the human disease. We hypothesized that experimental diabetes in rats combined with a cardiac or renal stressor, would mimic diabetic cardiomyopathy and nephropathy, respectively. Diabetes was surgically induced in male Sprague Dawley rats by 90% pancreatectomy (Px). Isoprenaline (Iso, 1 mg/kg, sc., 10 days) was administered 5 weeks after Px with the aim of inducing cardiomyopathy, and cardiac function and remodeling was assessed by echocardiography 10 weeks after surgery. Left ventricular (LV) fibrosis was quantified by Picro Sirius Red and gene expression analysis. Nephropathy was induced by Px combined with uninephrectomy (Px-UNx). Kidney function was assessed by measurement of glomerular filtration rate (GFR) and urine albumin excretion, and kidney injury was evaluated by histopathology and gene expression analysis. Px resulted in stable hyperglycemia, hypoinsulinemia, decreased C-peptide, and increased glycated hemoglobin (HbA1c) compared with sham-operated controls. Moreover, Px increased heart and LV weights and dimensions and caused a shift from α-myosin heavy chain (MHC) to β-MHC gene expression. Isoprenaline treatment, but not Px, decreased ejection fraction and induced LV fibrosis. There was no apparent interaction between Px and Iso treatment. The superimposition of Px and UNx increased GFR, indicating hyperfiltration. Compared with sham-operated controls, Px-UNx induced albuminuria and increased urine markers of kidney injury, including neutrophil gelatinase-associated lipocalin (NGAL) and podocalyxin, concomitant with upregulated renal gene expression of NGAL and kidney injury molecule 1 (KIM-1). Whereas Px and isoprenaline separately produced clinical endpoints related to diabetic cardiomyopathy, the combination of the two did not accentuate disease development. Conversely, Px in combination with UNx resulted in several clinical hallmarks of diabetic nephropathy indicative of early disease development.

A non-inferiority study to compare daily fast-acting insulin versus twice a week slow-acting insulin-moderate diabetes mode

Purpose

Given the high prevalence of diabetes (D), several animal models have been analyzed. In the literature, most of the animal models have studied severe D. However, in clinical practice, most patients have moderate disease. Therefore, the present study aimed to describe a moderate D condition.

Methods

We analyzed 20 Wistar rats, age eight-weeks, weight between 200g-250g. All animals received an intravenous injection of Streptozotocin (55mg/kg weight). On the 15th day after D induction, the animals were divided into two groups: Group I – animals receiving a single daily dose of fast-acting insulin (FAIG) NPH (1UI,SC) for partial glycemic control, and Group II - animals receiving slow-acting insulin(SAIG) twice a week. We measured glycemia, weight, and adverse events every week during two months.

Results

Of the total of animals analyzed in the study, three animals died in the FAIG and two animals died in the SAIG. Regarding the glycemic level, results were 339.5 ± 125.4mg/dL (95CI 302.3402 to 376.6842) in the FAIG, and 367.8 ± 66.1mg/dL (95IC 333.7607 to 401.8978) in the SAIG. There was no difference between groups as to weight during the study.

Conclusion

The use of slow-acting-insulin is not inferior to the use of fast-acting-insulin in the management of partially insulin-controlled moderate diabetes in rats.