Effect of mulberry leaf (Folium Mori) on insulin resistance via IRS-1/PI3K/Glut-4 signalling pathway in type 2 diabetes mellitus rats

Figures & data

Table 1. Summary of primers used in current study.

Gene	GenBank accession	Forward primer	Reverse primer	Size (bp)
IRS-1	NM_005544	ATGTGGAAATGGCTCGGA	TAAGGCAGCAAAGGGTAGGC	144
PI3K p85α	NM_005027	GAAGGCAACGAGAAGGA	CGTCAGCCACATCAAGTA	213
Glut-4	NM_001042	GCCATGAGCTACGTCTCCATT	GGCCACGATGAACCAAGGAA	90
Gapdh	NM_008084	AGGTCGGTGTGAACGGATTTG	TGTAGACCATGTAGTTGAGGTCA	123

Table 2. Effect of FME on FBG, plasma insulin and HOMA-IR.

	FBG level (mmol/l)		Serum insulin level (mU/l)		HOMA-IR
Group	0 day	28th day	0 day	28th day	0 day	28th day
NC	4.10 ± 0.65	3.29 ± 0.46	27.24 ± 2.76	17.95 ± 1.17	4.96 ± 0.37	2.62 ± 0.46
DBC	9.19 ± 1.73*	9.70 ± 3.55*	25.64 ± 2.28	20.27 ± 1.10*	10.47 ± 1.06*	8.74 ± 0.86*
RSG	8.29 ± 1.48*	9.09 ± 2.13*	28.34 ± 4.41	22.08 ± 1.79*	10.44 ± 0.75*	8.90 ± 0.95*
TCM	8.35 ± 1.76*	8.18 ± 1.52*^#	25.84 ± 1.93	18.95 ± 2.03	9.59 ± 1.11*	6.89 ± 0.83*^#
FME	7.91 ± 1.19*	6.76 ± 1.36*^#	27.22 ± 1.11	20.39 ± 1.57*	9.57 ± 0.75*	6.13 ± 0.87*^#

* p <  0.05, compared to the NC group;

# p <  0.05, compared to the DBC group.

Figure 1. FME protects against glucose intolerance in diabetic rats. (A) Blood glucose level at 0 min, 30 min, 1 h and 2 h after glucose was given at the dosage of 2 g/kg weight. (B) AUC of OGTT. Data were represented as mean ± SD (n = 7). *p <0.05, compared to the NC group; #p <0.05, compared to the DBC group.

Table 3. Effect of FME on TG, TC, HDL and LDL.

	TG (mmol/L)		TC (mmol/L)		HDL (mmol/L)		LDL (mmol/L)
Group	0 day	28th day	0 day	28th day	0 day	28th day	0 day	28th day
NC	0.66 ± 0.18	0.26 ± 0.06	1.45 ± 0.08	1.27 ± 0.20	1.08 ± 0.08	0.92 ± 0.15	0.39 ± 0.14	0.53 ± 0.07
DBC	2.08 ± 1.60*	1.09 ± 0.35*	6.66 ± 1.91*	3.22 ± 0.72*	0.96 ± 0.10	0.96 ± 0.16	2.99 ± 1.23*	1.22 ± 0.31*
RSG	2.21 ± 1.62*	0.72 ± 0.30*	8.01 ± 1.24*#	2.38 ± 0.34*#	1.13 ± 0.37	0.98 ± 0.12	4.37 ± 1.47*#	0.89 ± 0.19*#
TCM	1.43 ± 0.74*	0.28 ± 0.12#	5.39 ± 1.86*	1.96 ± 0.40*#	1.05 ± 0.29	1.08 ± 0.22	2.65 ± 0.88*	0.58 ± 0.12*#
FME	1.97 ± 0.22*	0.56 ± 0.19*#	4.75 ± 0.57*#	2.39 ± 0.32*#	0.89 ± 0.24	0.88 ± 0.09	1.24 ± 0.16*#	0.79 ± 0.09*#

* p <  0.05, compared to the NC group;

# p <  0.05, compared to the DBC group.

Figure 2. Effect of FME on mRNA expression of IRS-1, PI3K and Glut-4 in skeletal tissue. Data were represented as mean ± SD (n = 7). *p <0.05, compared to the NC group; #P <0.05, compared to the DBC group.

Figure 3. Effect of FME on protein expression in skeletal tissue (A). The relative expression of IRS-1 (B), PI3K (C) and Glut-4 (D) were calculated and were shown, respectively. Data were represented as mean ± SD (n = 7). *p <0.05, compared to the NC group; #p <0.05, compared to the DBC group.

Figure 4. Histological observation of skeletal tissues in experimental rats (HE staining, 40×), (A) NC group, (B) DBC group, (C) RSG group, (D) TCM group and (E) FME group.

Figure 5. Immunohistochemical staining of skeletal tissues with IRS-1 and pIRS-1 in experimental rats (40× magnification). (A)–(E) represented the staining of IRS-1 in the NC, DBC, RSG, TCM and FME groups, respectively. (F)–(J) represented the staining of pIRS-1 in the NC, DBC, RSG, TCM and FME groups, respectively.