High-dose naproxen aggravates pancreatic fibrosis in a rat model of chronic pancreatitis

Naproxen administration affects murine late folliculogenesis, reduces granulosa cell proliferation and the number of ovulated oocytes

Naproxen reduces the production of prostaglandins via inhibition of the cyclooxygenase. Studies have shown that its administration in women can be related to failed ovulation. Therefore, preclinical investigations must be performed in order to investigate its effects in experimental models. Thus, the aim of this study was to evaluate the effects of naproxen on murine folliculogenesis, ovulation, and female fertility. Female C57BL/6 mice (n = 128 - 6 weeks old) were divided into Control, low (10 mg/kg), and high naproxen (50 mg/kg) groups, who were treated for 8 days and directed to morphofunctional analyses. Follicular quantification showed a reduced percentage of antral follicles in naproxen-treated animals. These treated animals also showed smaller oocytes included in secondary and antral follicles, and the diameter of secondary and antral follicles was also reduced. A reduction in the percentage of Ki67-positive granulosa cells was observed in treated animals that also showed down-regulation of Igf1r compared to control. After an ovarian stimulation protocol, naproxen-treated animals showed a reduction in the percentage of secondary and antral follicles, a reduced number of ovulated oocytes and, corpora lutea, and an increased number of failed ovulations. Finally, naproxen-treated animals also showed a reduction in mating index and pregnancy rate. Our findings suggested that, in mice, naproxen administration (eight days treatment) negatively affects molecular and morphological aspects related to late folliculogenesis, ovulation, and fertility.

L-cysteine administration attenuates pancreatic fibrosis induced by TNBS in rats by inhibiting the activation of pancreatic stellate cell

BACKGROUND AND AIMS

Recent studies have shown that activated pancreatic stellate cells (PSCs) play a major role in pancreatic fibrogenesis. We aimed to study the effect of L-cysteine administration on fibrosis in chronic pancreatitis (CP) induced by trinitrobenzene sulfonic acid (TNBS) in rats and on the function of cultured PSCs.

METHODS

CP was induced by TNBS infusion into rat pancreatic ducts. L-cysteine was administrated for the duration of the experiment. Histological analysis and the contents of hydroxyproline were used to evaluate pancreatic damage and fibrosis. Immunohistochemical analysis of α-SMA in the pancreas was performed to detect the activation of PSCs in vivo. The collagen deposition related proteins and cytokines were determined by western blot analysis. DNA synthesis of cultured PSCs was evaluated by BrdU incorporation. We also evaluated the effect of L-cysteine on the cell cycle and cell activation by flow cytometry and immunocytochemistry. The expression of PDGFRβ, TGFβRII, collagen 1α1 and α-SMA of PSCs treated with different concentrations of L-cysteine was determined by western blot. Parameters of oxidant stress were evaluated in vitro and in vivo. Nrf2, NQO1, HO-1, IL-1β expression were evaluated in pancreas tissues by qRT-PCR.

RESULTS

The inhibition of pancreatic fibrosis by L-cysteine was confirmed by histological observation and hydroxyproline assay. α-SMA, TIMP1, IL-1β and TGF-β1 production decreased compared with the untreated group along with an increase in MMP2 production. L-cysteine suppressed the proliferation and extracellular matrix production of PSCs through down-regulating of PDGFRβ and TGFβRII. Concentrations of MDA+4-HNE were decreased by L-cysteine administration along with an increase in GSH levels both in tissues and cells. In addition, L-cysteine increased the mRNA expression of Nrf2, NQO1 and HO-1 and reduced the expression of IL-1β in L-cysteine treated group when compared with control group.

CONCLUSION

L-cysteine treatment attenuated pancreatic fibrosis in chronic pancreatitis in rats.

Smoking is related to pancreatic fibrosis in humans

OBJECTIVES

Smokers are at risk for pancreatic cancer (PC) and other pancreatic diseases. Cigarette smoking also aggravates the risk of PC in patients with hereditary and chronic pancreatitis (CP) and results in a higher incidence of acute pancreatitis and relapses in CP. Both PC and CP are characterized by a progressive fibrosis. Recently, two studies on rats reported that tobacco smoking is associated with chronic pancreatic inflammation with fibrosis and scarring of pancreatic acinar structures. In this study, we aimed to confirm a relationship between cigarette smoking and pancreatic fibrosis (PF) in humans.

METHODS

In this retrospective study, pancreatic and liver tissue acquired during autopsy was collected and analyzed. PF was scored by assessing severity of intralobular, extralobular, and total PF: grade 0 (normal or mild; 0-25% PF), grade 1 (moderate; 25-50% PF), and grade 2 (severe; >50%). Information on smoking habits was extracted from (electronic) medical records.

RESULTS

Of 900 autopsies performed from January 2005 to December 2007, a minority of patients (n=111) met all inclusion criteria for analysis. Grade 2-3 total PF and intralobular PF was significantly more present in smokers vs. "never-smokers" (total: 42.9 vs. 26.5%, P=0.027 and intralobular: 39.3 vs. 15.6%, P=0.013), whereas no differences could be found between never-smokers and ex-smokers and between ex-smokers and smokers. When we took into account interlobular PF, no differences between all groups were observed. No relationship between PF and age (P=0.893), body mass index (P=0.707), and pancreatic lipomatosis (P=0.916) was observed.

CONCLUSIONS

To our knowledge, no study in humans had studied the effect of tobacco smoking on pancreatic tissue. We have demonstrated for the first time that current cigarette smoking is associated with total PF-specifically, intralobular PF-as compared with nonsmokers.

Proteinase-activated receptor 2 mediates thermal hyperalgesia and is upregulated in a rat model of chronic pancreatitis

OBJECTIVES

The mechanism of pain in chronic pancreatitis (CP) has yet to be explored. Proteinase-activated receptor 2 (PAR2) plays a pronociceptive role in visceral pain. The study aimed to assess the expression of PAR2 in dorsal root ganglia (DRGs) and validate its role of thermal hyperalgesia in CP.

METHODS

Chronic pancreatitis model was induced by trinitrobenzene sulfonic acid infusion into rat pancreatic ducts. Abdominal hyperalgesia was measured by thermal withdrawal latencies. The expression of PAR2 and transient receptor potential vanilloid 1 (TRPV1) were analyzed by immunofluorescence and Western blot. The messenger RNA encoding PAR2 was quantitated by real-time polymerase chain reaction. The effects of short-term and long-term ulinastatin treatment on abdominal thermal hyperalgesia of rats with CP were measured.

RESULTS

Rats with CP showed a decreased thermal withdrawal latency. Proteinase-activated receptor 2 and TRPV1 were significantly upregulated in DRGs. The increased PAR2 protein expression was tightly correlated with thermal withdrawal latencies and TRPV1 expression. Short-term ulinastatin treatment inhibited the development of thermal hyperalgesia of rats with CP in a dose-dependent manner.

CONCLUSIONS

The thermal hyperalgesia in CP is associated with an up-regulation of the PAR2 in DRGs. Proteinase-activated receptor 2 was involved in the pain generation in rats with CP.