Diarrhea

Effects of electronically stimulating Tianshu (ST 25) and Dachangshu (BL 25), Quchi (LI 11) and Shangjuxu (ST 37) on the expressions of jejunum c-kit protein and c-kit mRNA in rats with functional diarrhea

OBJECTIVE

To investigate the effects of electronically stimulating Tianshu (ST 25) and Dachangshu (BL 25), Quchi (LI 11) and Shangjuxu (ST 37) on the jejunum c-kit protein and c-kit mRNA in rats with functional diarrhea (FD).

METHODS

FD models were established through intragastric administration with folium sennae. Experimental rats were then divided into 4 groups: blank group, model group, electroacupuncture group Ⅰ [Tianshu (ST 25) and Dachangshu (BL 25) of both sides] and electroacupuncture group Ⅱ [Quchi (Li 11) and Shangjuxu (ST 37) of both sides], 10 in each. After treatment with electroacupuncture for 10 days, The expressions of jejunum c-kit protein and c-kit mRNA in each group were detected with Western blot and Real-Time quantitative real-time polymerase chain reaction (PCR).

RESULTS

The expressions of c-kit protein and c-kit mRNA in the model group increased significantly compared to those in the blank group (P < 0.01); the expressions in electroacupuncture group Ⅰsignificantly decreased compared to those in the model group (P < 0.01).

CONCLUSION

Our findings suggest that electronicall stimulating both Tianshu (ST 25) and Dachangshu (BL 25) significantly increased the expressions of jejunum c-kit protein and c-kit mRNA in FD rats, which means the treatment might have better therapeutic effects on FD.

Chemotherapeutic agent CPT-11 eliminates peritoneal resident macrophages by inducing apoptosis

CPT-11 (Irinotecan) is a first-line chemotherapeutic agent in clinic, but it may induce side effects including diarrhea and enteritis in patients. The underlying mechanism of CPT-11's intestinal toxicity is unclear. Peritoneal resident macrophages have been reported to be important for the maintenance of intestinal homeostasis. In this study, we evaluated the cytotoxic effects of CPT-11 on mouse peritoneal resident macrophages. CPT-11 was administered intraperitoneally to mice and their peritoneal exudate cells were isolated for evaluation. CPT-11 treatment strikingly decreased the ratio of F4/80(hi)MHCII(low) large peritoneal macrophages (LPMs), which are regarded as prenatally-originated peritoneal resident macrophages. Consistent with this, the transcription factor GATA6 specifically expressed in LPMs was barely detectable in the macrophages from CPT-11-treated mice, indicative of elimination of LPMs. Such elimination of LPMs was at least partly due to CPT-induced apoptosis in macrophages, because inhibition of apoptosis by caspase-3 inhibitor z-DEVD-fmk significantly diminished the loss of GATA6(+) LPMs. As GATA6 is a transcription factor that controls expression of multiple genes regulating peritoneal B-1 cell development and translocation, elimination of GATA6(+) LPMs led to a great reduction in B-1 cells in the peritoneal cavity after CPT-11 treatment. These results indicated that CPT-11-induced apoptosis contributed to the elimination of peritoneal resident macrophages, which might in turn impair the function of peritoneal B-1 cells in maintaining intestinal homeostasis. Our findings may at least partly explain why CPT-11 treatment in cancer patients induces diarrhea and enteritis, which may provide a novel avenue to prevent such side effects.

Diacerein protects against iodoacetate-induced osteoarthritis in the femorotibial joints of rats

The present study was undertaken to investigate the effect of diacerein on the histopathology of articular cartilage and subchondral bone of the femorotibial joint in rats. Osteoarthritis was induced in rats after single intra-articular injection of sodium iodoacetate. Rats were sacrificed 1, 2, 4, and 8 weeks post intra-articular injection to evaluate the progression of histopathogenesis of osteoarthritis. Diacerein was orally administered (15 mg/kg) once daily post 1 and 2 weeks of iodoacetate injection in two groups, respectively, for up to 12 weeks. Articular cartilage and subchondral bone of the rats of both groups were examined after 8 and 12 weeks, respectively. Quantitative histological analyses were performed by scoring these sections as per the OARSI system. Chondroitin sulfate was also estimated in articular cartilage by decrease in absorbance of methylene blue on complexation with chondroitin sulfate using a spectrophotometer. Intra-articular injection of iodoacetate induced loss of articular cartilage with progressive subchondral bone sclerosis and degeneration. Based on histopathological and biochemical findings, diacerein treatment showed chondroprotective effect. Furthermore, the chondroprotective effect of diacerein was found to be more pronounced after 12 weeks as compared to 8 weeks in both cases (i.e., post 1 and 2 weeks of iodoacetate injection). Similar results were observed by investigation of chondroitin sulfate during biochemical study, showing the chondroprotective effect. In conclusion, diacerein exhibits chondroprotective effect in rats with late onset of action.

Targeting of diacerein loaded lipid nanoparticles to intra-articular cartilage using chondroitin sulfate as homing carrier for treatment of osteoarthritis in rats

Targeted delivery of antiosteoarthritic drug diacerein to articular tissue could be a major achievement and soluble polysaccharide chondroitin sulfate (ChS) may be a suitable agent for this. Therefore, diacerein loaded solid lipid nanoparticles modified with ChS (ChS-DC-SLN) were prepared for synergistic effect of these agents to combat multidimensional pathology of osteoarthritis (OA). Prepared formulation were of size range 396±2.7nm, showed extended release up to 16h and increased bioavailability of diacerein by 2.8 times. ChS-DC-SLN were evaluated for their effect on histopathology of femoro-tibial joint of rat knee and amount of ChS and rhein (an active metabolite of diacerein) at targeted site. Concentration of rhein was significantly higher in case of ChS-DC-SLN (7.8±1.23μg/ml) than that of drug dispersion (2.9±0.45μg/ml). It can be stated that ChS served as homing to articular cartilage for targeting of drug. Thus, ChS-DC-SLN have great potential to enhance the overall efficacy of treatment for OA.

FROM THE CLINICAL EDITOR

This study demonstrates the feasibility of targeted delivery of diacerein to articular tissue using soluble polysaccharide chondroitin sulfate as the targeting vector. This approach has the potential to significantly increase anti-arthritic drug concentration in joints without leading to systemic toxicity.

The role of purinergic pathways in the pathophysiology of gut diseases: pharmacological modulation and potential therapeutic applications

Gut homeostasis results from complex neuro-immune interactions aimed at triggering stereotypical and specific programs of coordinated mucosal secretion and powerful motor propulsion. A prominent role in the regulation of this highly integrated network, comprising a variety of immune/inflammatory cells and the enteric nervous system, is played by purinergic mediators. The cells of the digestive tract are literally plunged into a "biological sea" of functionally active nucleotides and nucleosides, which carry out the critical task of driving regulatory interventions on cellular functions through the activation of P1 and P2 receptors. Intensive research efforts are being made to achieve an integrated view of the purinergic system, since it is emerging that the various components of purinergic pathways (i.e., enzymes, transporters, mediators and receptors) are mutually linked entities, deputed to finely modulating the magnitude and the duration of purinergic signaling, and that alterations occurring in this balanced network could be intimately involved in the pathophysiology of several gut disorders. This review article intends to provide a critical appraisal of current knowledge on the purinergic system role in the regulation of gastrointestinal functions, considering these pathways as a whole integrated network, which is capable of finely controlling the levels of bioactive nucleotides and nucleosides in the biophase of their respective receptors. Special attention is paid to the mechanisms through which alterations in the various compartments of the purinergic system could contribute to the pathophysiology of gut disorders, and to the possibility of counteracting such dysfunctions by means of pharmacological interventions on purinergic molecular targets.