Involvement of Mast-Cell-Tryptase- and Protease-Activated Receptor 2-Mediated Signaling and Urothelial Barrier Dysfunction with Reduced Uroplakin II Expression in Bladder Hyperactivity Induced by Chronic Bladder Ischemia in the Rat

We aimed to investigate the relationship between mast cell (MC) infiltration into the bladder with urothelial barrier dysfunction and bladder hyperactivity in a chronic bladder ischemia (CBI) rat model. We compared CBI rats (CBI group; n = 10) with normal rats (control group; n = 10). We measured the expression of mast cell tryptase (MCT) and protease-activated receptor 2 (PAR2), which are correlated with C fiber activation via MCT, and Uroplakins (UP Ia, Ib, II and III), which are critical to urothelial barrier function, via Western blotting. The effects of FSLLRY-NH2, a PAR2 antagonist, administered intravenously, on the bladder function of CBI rats were evaluated with a cystometrogram. In the CBI group, the MC number in the bladder was significantly greater (p = 0.03), and the expression of MCT (p = 0.02) and PAR2 (p = 0.02) was significantly increased compared to that of the control group. The 10 μg/kg FSLLRY-NH2 injection significantly increased the micturition interval of CBI rats (p = 0.03). The percentage of UP-II-positive cells on the urothelium with immunohistochemical staining was significantly lower in the CBI group than in the control group (p < 0.01). Chronic ischemia induces urothelial barrier dysfunction via impairing UP II, consequently inducing MC infiltration into the bladder wall and increased PAR2 expression. PAR2 activation by MCT may contribute to bladder hyperactivity.

Echinochrome A Treatment Alleviates Atopic Dermatitis-like Skin Lesions in NC/Nga Mice via IL-4 and IL-13 Suppression

Atopic dermatitis (AD) is a chronic inflammatory skin disease in which skin barrier dysfunction leads to dryness, pruritus, and erythematous lesions. AD is triggered by immune imbalance and oxidative stress. Echinochrome A (Ech A), a natural pigment isolated from sea urchins, exerts antioxidant and beneficial effects in various inflammatory disease models. In the present study, we tested whether Ech A treatment alleviated AD-like skin lesions. We examined the anti-inflammatory effect of Ech A on 2,4-dinitrochlorobenzene (DNCB)-induced AD-like lesions in an NC/Nga mouse model. AD-like skin symptoms were induced by treatment with 1% DNCB for 1 week and 0.4% DNCB for 5 weeks in NC/Nga mice. The results showed that Ech A alleviated AD clinical symptoms, such as edema, erythema, and dryness. Treatment with Ech A induced the recovery of epidermis skin lesions as observed histologically. Tewameter^® and Corneometer^® measurements indicated that Ech A treatment reduced transepidermal water loss and improved stratum corneum hydration, respectively. Ech A treatment also inhibited inflammatory-response-induced mast cell infiltration in AD-like skin lesions and suppressed the expression of proinflammatory cytokines, such as interferon-γ, interleukin-4, and interleukin-13. Collectively, these results suggest that Ech A may be beneficial for treating AD owing to its anti-inflammatory effects.

Echinochrome A Protects against Ultraviolet B-induced Photoaging by Lowering Collagen Degradation and Inflammatory Cell Infiltration in Hairless Mice

Echinochrome A (Ech A, 7-ethyl-2,3,5,6,8-pentahydroxy-1,4-naphthoquinone) has been known to exhibit anti-oxidative and anti-inflammatory effects. However, no study has been carried out on the efficacy of Ech A against skin photoaging; this process is largely mediated by oxidative stress. Six-week-old male SKH-1 hairless mice (n = 36) were divided into five groups. Except for a group that were not treated (n = 4), all mice underwent ultraviolet-B (UVB) exposure for 8 weeks while applying phosphate-buffered saline or Ech A through intraperitoneal injection. UVB impaired skin barrier function, showing increased transepidermal water loss and decreased stratum corneum hydration. UVB induced dermal collagen degeneration and mast cell infiltration. Ech A injection was found to significantly lower transepidermal water loss while attenuating tissue inflammatory changes and collagen degeneration compared to the control. Furthermore, Ech A was found to decrease the relative expression of matrix metalloproteinase, tryptase, and chymase. Taken together, these results suggest that Ech A protects against UVB-induced photoaging in both functional and histologic aspects, causing a lowering of collagen degradation and inflammatory cell infiltration.

Topical film prepared with Rhus verniciflua extract-loaded pullulan hydrogel for atopic dermatitis treatment

Atopic dermatitis (AD) is characterized by relapsing pruritus and skin dryness. Due to the pathogenic multiplicity and the adverse effects associated with the current therapeutics, development of transdermal drug delivery system is becoming an area of interest. Here, a novel topical film prepared with Rhus verniciflua extract (RVE)-loaded pullulan hydrogel (RVE@PH) was synthesized and tested its therapeutic efficacy on the AD rats modeled by neonatal capsaicin injection method. The RVE@PH was characterized by a Fourier-transform infrared spectroscopy and an in vitro release assay. Rat pups were randomly divided into two groups: vehicle-treated (VEH; n = 5) and capsaicin-treated (n = 15). The latter were given capsaicin subcutaneously at 24 h after birth for AD induction and further divided into three groups (n = 5 per each): not treated (CAP), pullulan hydrogel-applied (PH), and RVE@PH-applied (RVE-PH). The pullulan hydrogel and RVE@PH were topically applied on shoulder lesions for 14 days (from 42 to 56 days after birth). Their phenotypes were compared based on the dermatitis score, epidermal thickness, mast cell infiltration, and serum myeloperoxidase (MPO) activities. The PH group showed significant attenuation in all the aforementioned values compared to the CAP group, suggesting that pullulan hydrogel itself has therapeutic activity against AD. Notably, the attenuations were more potent in the RVE-PH group than the PH group, indicating that the therapeutic efficacy against AD is augmented by the presence of RVE, a loaded pharmaceutic. Collectively, these results indicate that RVE@PH inhibits AD through exerting the dual roles, that is, the pullulan hydrogel-mediated physical and RVE-mediated pharmaceutical actions. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2325-2334, 2019.

Antiallergic effect of an aqueous leaf extract of Pistia stratiotes in murine model of ovalbumin-induced allergic conjunctivitis

Aim:

The aim was to investigate the antiallergic effect of an aqueous leaf extract of Pistia stratiotes (ALPS) in a murine model of ovalbumin (OVA)-induced allergic conjunctivitis (AC).

Materials and Methods:

Prior to topical challenge (instillation of 1.5 mg OVA in 10 μL phosphate buffered saline into their conjunctival sacs) to induce AC, groups of sensitized Imprinting Control Region mice (injected IP, on day 1 and 7, with 0.2 ml solution of 100 μg OVA and 0.01 mg aluminum hydroxide in phosphate buffered saline), were treated with 5 mg/kg cetirizine, 10, 50 or 100 mg/kg of ALPS, or 2 ml/kg normal saline per os. Conjunctival redness, lid edema, tearing and lid scratching (clinical symptoms of AC) were scored. Serum OVA specific immunoglobulins were determined using ELISA. Histopathological assessment of the conjunctival mucosal tissue was conducted. The extract was screened for secondary plant metabolites.

Results:

Pretreatment with the extract significantly (P ≤ 0.05–0.01) and dose-dependently reduced the scores for clinical symptoms, which were marked in vehicle-pretreated mice. Pretreatment also lowered (P ≤ 0.01–0.001) serum OVA specific immunoglobulins. Mast cell infiltration and degranulation in conjunctival stroma (measured by an inflammatory score) in histopathological studies was also significantly low (P ≤ 0.05–0.01) on pretreatment.

Conclusion:

The ALPS exhibited interesting antiallergic activity and hence could be useful in managing AC.