Both spleen and ear obtained from BALB / c-nu were used for qRT-PCR analysis, and skin tissue obtained from both species was used for Histological analysis and qRT-PCR analysis.
3.1 Assessment of C-PC in the BALB/c-nu mice psoriasis model
To induce plaque psoriasis in BALB/c-nu mice, imiquimod cream was applied. These mice exhibited characteristic scaling, redness, and thickness with silver scales. In this study, mometasone furoate (NovasoneTM cream), used as a positive control, eliminated silver scales. Similarly, C-PC eliminated the presence of silver scales from the psoriatic skin mice in which psoriasis was induced (Fig. 1a). With respect to the severity scores, the experimental group with imiquimod-induced psoriasis demonstrated higher scores in both ear and dorsal skin when compared to the experimental group treated with 1 µg and 5 µg C-PC. (Fig. 2a). These results showed a more positive than effect of mometasone furoate. However, the image and severity scores were negatively affected when the animals were treated with more than 10 µg C-PC.
3.1.1. Downregulation of IL-6, IL-1b, COX-2, and TNF-α mRNA expression in BALB/c-nu mice
IL-1b is expressed in activated macrophage cells and is involved in cell proliferation, differentiation, and apoptosis. Following the induction of psoriasis, IL-1b levels increase, which then induce the expression of COX-2 and COX-2 in psoriasis [15, 17]. Furthermore, the levels of the pro-inflammatory factor, IL-6, and inflammatory factor, TNF-α, are reportedly increased following the induction of psoriasis . We treated imiquimod-induced psoriatic BALB/c-nu with C-PC and mometasone, and collected the dorsal and ear skin, as well as the spleen. After isolating the tissue RNA, qRT-PCR was performed to measure the expression of four cytokines (IL-6, IL-1b, COX-2, and TNF-α). In the ear skin, the levels of TNF-α continuously decreased as the C-PC concentration increased; COX-2 expression was also decreased (Fig. 5). However, treatment with 10 µg C-PC marginally increased the expression of TNF-α and COX-2 when compared to the experimental group treated with 5 µg C-PC. Similarly, for tissues derived from the spleen and dorsal skin, qRT-PCR demonstrated that the expression of IL-1b, COX-2, IL-6, and TNF-α decreased following C-PC treatment (Fig. 5).
3.1.2. Histological analysis of C-PC in the BALB/c-nu psoriasis model
Following the induction of psoriasis, the stratum corneum thickened, with cell clusters observed in the epidermal layer [7, 25]. In normal skin tissue (sham), the epidermis consists of 2‒3 epithelial layers, with a stack of stratum granulosum, stratum spinosum, and stratum basale; the dermis is located below the epidermis, and is composed of hair follicles, sebaceous glands, and the extracellular matrix. However, tissues from the imiquimod-treated animals exhibited 4‒16 thickened epidermal layers (Fig. 3). In the sham, psoriasis, and mometasone-treated groups, the epidermal thickness was 33.534 μm, 88.727 μm, and 31.338 μm, respectively (Table. 2). The C-PC-treated group demonstrated an epidermal thickness that was comparable to that observed in the mometasone-treated group; however, histological differences were not significant among C-PC treated samples.
3.2 Assessment of C-PC in the BALB/c mouse psoriasis model
Psoriasis was induced in BALB/c mice using imiquimod cream. Similar to that in the BALB/c-nu mice, the degree of redness and scaling was lowered in all groups treated with mometasone and C-PC when compared to the imiquimod-treated group (Fig. 1b). However, in the 10 μg C-PC treated group, psoriasis symptoms were more severe than those observed in the imiquimod-treated group. Similar scores were observed in terms of the severity of inflammation (Fig. 2b).
3.3.1. Downregulation of IL-1b, COX-2, TNF- α, IL-17a, IFN-γ, and CGRP mRNA expression in BALB/c mouse
Reportedly, the expression of COX-2, IL-1b, TNF-α, IFN-γ, IL-17a, and CGRP mRNA is known to increase in psoriasis [14-17]. In the BALB/C psoriasis model, the negative group treated with imiquimod demonstrated an increased expression of all six factors when compared with the sham and positive groups. The groups treated with 1 μg, 2 μg, and 5 μg C-PC showed a similar or more effective decrease in COX-2 and IL-1b expression when compared with the positive group (Fig. 6). Following treatment with 1 μg C-PC, the expression of TNF-α and CGRP was lowered compared to that observed in the sham group; however, the other C-PC concentrations failed to effectively decrease the expression of these molecules. IFN-γ expression was decreased in the mometasone-treated group, but no significant change was observed in the C-PC treated groups. In the 1 μg, 2 μg, and 5 μg C-PC treated groups, the expression of IL-17a was altered to levels observed in the sham group. Following treatment with 10 μg C-PC, the expression of all factors was higher than that observed in the negative group.
3.3.2. Histological analysis in C-PC-treated BALB/c psoriasis model
In the sham, psoriasis, and mometasone-treated groups, the epidermal thickness was 23.86 μm, 57.06 μm, and 38.98 μm, respectively (Table.3). In the 1 μg treated C-PC group, the results were similar to those observed in the mometasone-treated group (Fig. 4). However, treatment with more than 2 μg of C-PC demonstrated minimal effects on the thickness of the epidermal layer.