Undenatured Type II Collagen Ameliorates Inflammatory Responses and Articular Cartilage Damage in the Rat Model of Osteoarthritis

Abstract

Osteoarthritis (OA) is an age-related joint disease that includes gradual disruption of the articular cartilage and the resulting pain. The present study was designed to test the effects of undenatured type II collagen (UC-II®) on joint inflammation in the monoiodoacetate (MIA) OA model. We also investigated possible mechanisms underlying these effects. Female Wistar rats were divided into three groups: (i) Control; (ii) MIA-induced rats treated with vehicle; (iii) MIA-induced rats treated with UC-II (4 mg/kg BW). OA was induced in rats by intra-articular injection of MIA (1 mg) after seven days of UC-II treatment. UC-II reduced MIA-induced Kellgren-Lawrence scoring (53.3%, P < 0.05). The serum levels of inflammatory cytokines [IL-1β (7.8%), IL-6 (18.0%), TNF-α (25.9%), COMP (16.4%), CRP (32.4%)] were reduced in UC-II supplemented group (P < 0.0001). In the articular cartilage, UC-II inhibited the production of PGE2 (19.6%) and the expression of IL-1β, IL-6, TNF-a, COX-2, MCP-1, NF-κB, MMP-3, RANKL (P < 0.001). The COL-1 and OPG levels were increased, and MDA decreased in UC-II supplemented rats (P < 0.001). UC-II could be useful to alleviate joint inflammation and pain in OA joints by reducing the expression of inflammatory mediators.

Keywords: MIA; Nf-κB; UC-II; inflammation; osteoarthritis.

Figure 1

Effect of undenatured type II collagen (UC-II) supplementation on serum interleukin-1β (IL-1β; A), interleukin-6 (IL-6; B), tumor necrosis factor α (TNF-α; C), cartilage oligometrix matrix protein (COMP; D), c-reactive protein (CRP; E), prostaglandin E2 (PGE2; F), and osteocalcin (OCN; G) levels in monosodium iodoacetate (MIA) induced osteoarthritis rats (n = 7). The bars represent the mean and standard deviation of data. ANOVA and Tukey's post-hoc test were used to compare the results among different treatment groups. Statistical significance between groups is shown by ^***P < 0.001 compared to the control group and ^##P < 0.01, ^###P < 0.001 compared to the MIA group.

Figure 2

Effect undenatured type II collagen (UC-II) on serum malondialdehyde (MDA; A), superoxide dismutase (SOD; B), catalase (CAT; C), and glutathione peroxidase (GSHPx; D) levels in monosodium iodoacetate (MIA) induced osteoarthritis rats (n = 7). The bars represent the mean and standard deviation of data. ANOVA and Tukey's post-hoc test were used to compare the results among different treatment groups. Statistical significance between groups is shown by: ^***P < 0.001 as compared to the control group and ^#P < 0.05 as compared to MIA group.

Figure 3

Effect undenatured type II collagen (UC-II) on stride length (C), paw area (D), and paw width (E) in monosodium iodoacetate (MIA) induced osteoarthritis rats (n = 7). Representative measures of stride length (A), paw area (B) and paw width (B) are shown. The bars represent the mean and standard deviation of data. ANOVA and Tukey's post-hoc test were used to compare the results among different treatment groups. Statistical significance between groups is shown by ^**P < 0.01, ^***P < 0.001 compared to the control group and ## P < 0.01 compared to the MIA group.

Figure 4

Effect of undenatured type II collagen (UC-II) on knee swelling (A) and right knee joint diameter (B) in monosodium iodoacetate (MIA) induced osteoarthritis rats (n = 7). The bars represent the mean and standard deviation of data. ANOVA and Tukey's post-hoc test were used to compare the results among different treatment groups. Statistical significance between groups is shown by: ^*P < 0.05 as compared to the control group.

Figure 5

Effect of undenatured type II collagen (UC-II) on the knee joint radiographic and histopathologic findings in monosodium iodoacetate (MIA) induced osteoarthritis rats (n = 7). Representative radiographic (A) and histopathologic (B) images obtained at the end of the experiment are shown. Kellgren-Lawrence and Mankin scores were shown in (C) and (D), respectively. The bars represent the mean and standard deviation of data. Mann-Whitney U test were used to compare the results among different treatment groups. Statistical significance between groups is shown by: ^#P < 0.05 as compared to the MIA group.

Figure 6

Effect of undenatured type II collagen (UC-II) on knee joint protein expression of interleukin-1β (IL-1β; A), interleukin-6 (IL-6; B), tumor necrosis factor α (TNF-α; C), interferon regulatory factor 7 (IRF7; D), cyclooxygenase-2 (COX-2; E), nuclear factor-kappa B kinase subunit gamma (IKK-γ; F), monocyte chemoattractant protein-1 (MCP-1; G), and nuclear factor kappa B (NF-κB; H) levels in monosodium iodoacetate (MIA) induced osteoarthritis rats (n = 7). The densitometric analysis of the relative intensity according to the control group of the western blot bands was performed with β-actin normalization to ensure equal protein loading. Blots were repeated at least three times (n = 3) and representative blots are shown. The bars represent the mean and standard deviation of data. ANOVA and Tukey's post-hoc test were used to compare the results among different treatment groups. Statistical significance between groups is shown by: ^**P < 0.01, ^***P < 0.001 as compared to control group and, ^### P < 0.001 as compared to MIA group.

Figure 7

Effect of undenatured type II collagen (UC-II) on knee joint protein expression of metalloproteinase 3 (MMP-3; A), collagen type 1 (COL-1; B), osteoprotegerin (OPG; C), and receptor activator of NF-κB ligand (RANKL; D) levels in monosodium iodoacetate (MIA) induced osteoarthritis rats (n = 7). The densitometric analysis of the relative intensity according to the control group of the western blot bands was performed with β-actin normalization to ensure equal protein loading. Blots were repeated at least three times (n = 3) and representative blots are shown. The bars represent the mean and standard deviation of data. ANOVA and Tukey's post-hoc test were used to compare the results among different treatment groups. Statistical significance between groups is shown by: ^***P < 0.001 as compared to the control group and, ^### P < 0.001 as compared to MIA group.