Evaluation of biodegradable electric conductive tube-guides and mesenchymal stem cells

Table 1 Static sciatic functional index

SSI		Time
		T0	T1	T2	T4	T6	T8	T10	T12	T14	T16	T18	T20
Group 1: PVA	Mean	-3.13	-40.52	-52.76	-69.60	-60.30	-56.59	-63.51	-54.89	-40.25	-44.03	-57.34	-48.23
(n = 7)	SD	24.17	19.25	17.78	9.56	19.69	13.19	8.05	11.96	13.33	9.07	21.81	7.25
Group 2: PVA-CNTs	Mean	12.10	-41.85	-45.81	-68.07	-51.18	-52.22	-49.31	-44.52	-48.73	-37.65	-38.47	-38.99
(n = 7)	SD	34.10	20.82	23.21	17.00	11.41	41.96	21.11	17.62	26.31	20.78	17.97	31.11
Group 3: PVA-PPy	Mean	5.31	-41.40	-50.95	-45.76	-47.40	-34.56	-39.51	-31.52	-32.47	-43.17	-50.00	-36.08b
(n = 7)	SD	17.51	17.52	23.99	29.92	22.53	14.00	25.05	15.10	20.78	25.52	11.77	16.09
Group 4: Graft	Mean	-6.29	-56.46	-52.18	-55.41	-63.81	-59.79	-75.56	-53.15	-64.53	-67.22	-57.95	-52.07
(n = 4)	SD	1.59	28.10	27.54	27.99	19.06	11.00	10.45	15.44	12.14	12.17	8.31	9.76
Group 5: End-to-End	Mean	-5.78	-44.21	-33.72	-58.28	-73.92	-70.22	-52.47	-68.04	-41.91	-46.56	-43.04	-59.97
(n = 5)	SD	12.91	15.34	15.72	22.25	6.82	6.44	27.43	11.02	24.55	16.79	12.31	2.64
Group 6: PVA-CNTs-MSCs	Mean	3.46	-31.48	-23.75	-28.57	-39.97	-40.30	-62.32	-34.71	-26.28	-42.87	-37.54	-36.16b
(n = 7)	SD	12.35	21.89	19.70	9.96	9.20	21.72	18.07	16.44	15.31	25.75	10.06	14.87

Static sciatic functional index (SSI) measured pre-operatively (week-0), and every week after the surgical procedure until week-20. An index score of 0 is considered normal and an index of 100 indicates total impairment. The measurements of the toe spread (TS), and the intermediary TS, were taken from the experimental (E) and normal (N) sides. Results are presented as mean and SD. n corresponds to the number of rats within the experimental group. PVA: Polyvinyl alcohol; CNTs: Carbon nanotubes; PPy: Polypyrrole; MSCs: Mesenchymal stem cells.

^bP < 0.01 vs Graft.

Table 2 Withdrawal reflex latency

WRL		Time
		T0	T1	T2	T4	T6	T8	T10	T12	T14	T16	T18	T20
Group 1: PVA	Mean	3.71	10.95	10.81	10.68	9.74	10.23	9.85	8.15	7.78	9.99	7.88	6.98a
(n = 7)	SD	0.93	1.45	2.04	2.26	2.89	2.50	2.81	2.70	3.50	2.49	3.72	3.72
Group 2: PVA-CNTs	Mean	5.36	9.91	8.98	7.50	8.40	9.48	9.51	6.92	6.60	8.43	5.88	5.83a
(n = 7)	SD	1.50	3.57	3.65	3.36	3.22	3.41	3.01	3.49	3.41	3.40	3.09	2.80
Group 3: PVA-PPy	Mean	4.86	11.42	9.37	7.10	7.85	8.82	9.72	6.87	7.02	7.09	6.06	7.02a
(n = 7)	SD	1.69	1.54	3.31	2.51	3.40	2.53	2.35	3.50	3.92	3.23	4.43	3.89
Group 4: Graft	Mean	4.53	12.00	10.14	11.17	11.50	10.67	10.83	11.16	9.81	10.46	9.92	9.68a
(n = 4)	SD	1.14	0.00	3.72	1.66	1.01	2.65	2.35	1.27	2.84	1.78	1.82	1.88
Group 5: End-to-End	Mean	4.28	12.00	11.85	12.00	10.22	10.45	8.78	10.48	9.26	8.57	9.82	7.50
(n = 5)	SD	0.86	0.00	0.34	0.00	2.50	2.12	2.22	2.86	3.07	0.98	2.02	0.87
Group 6: PVA-CNTs-MSCs	Mean	3.93	12.00	8.89	9.23	9.30	9.90	7.65	7.41	10.06	8.33	8.28	8.02a
(n = 7)	SD	0.86	0.00	2.36	1.63	2.72	2.66	2.51	2.33	1.85	2.86	2.34	1.20

Values in seconds were obtained performing withdrawal reflex latency (WRL) test to evaluate the nociceptive function. This test has been performed pre-operatively (week-0), at week 1, week 2 and every 2 week after the surgical procedure until week-20, when the animals were sacrificed for morphological analysis. Results are presented as mean and standard error of the mean (SD). n corresponds to the number of animals within each experimental group. PVA: Polyvinyl alcohol; CNTs: Carbon nanotubes; PPy: Polypyrrole; MSCs: Mesenchymal stem cells.

^aP < 0.05 vs End-to-End.

Table 3 Ankle kinematics

Temporal events	Group	Week 20
IC	Group 1: PVA	-3.23 ± 20.65
	Group 2: PVA-CNTs	-8.32 ± 17.36
	Group 3: PVA + PPy	0.82 ± 26.33
	Group 6: PVA-MSCs	-13.68 ± 8.57
OT	Group 1: PVA	28.30 ± 19.52
	Group 2: PVA-CNTs	27.67 ± 12.91
	Group 3: PVA + PPy	17.66 ± 13.20
	Group 6: PVA-MSCs	11.43 ± 9.69
HR	Group 1: PVA	46.67 ± 14.81
	Group 2: PVA-CNTs	47.69 ± 11.19
	Group 3: PVA + PPy	36.46 ± 10.14
	Group 6: PVA-MSCs	34.07 ± 6.85
TO	Group 1: PVA	33.99 ± 9.57
	Group 2: PVA-CNTs	27.01 ± 10.99
	Group 3: PVA + PPy	43.90 ± 8.76
	Group 6: PVA-MSCs	20.56 ± 11.31

Values were obtained performing video analysis at 20-wk of the healing period. Results are presented as mean and standard deviation (SD) (n = 7). For each step cycle the following time points were identified: Initial contact (IC), opposite toe off (OT), heel rise (HR) and toe-off (TO). PVA: Polyvinyl alcohol; CNTs: Carbon nanotubes; PPy: Polypyrrole.

Table 4 Stereological quantitative assessment

Group		Density	Total	Axon	Fiber	Myelin	M/d	D/d	d/D	Area
			number	diameter (d)	diameter (D)	thickness (M)			(g-ratio)	(mm2)
Group 1: PVA	Mean	42872	16596	2.95	3.56	0.31a	0.11a	1.23	0.82a	0.3862
(n = 7)	SD	4007	1741	0.25	0.28	0.03	0.01	0.02	0.01	0.0772
Group 2: PVA-CNTs	Mean	36261	16049	2.98	3.71	0.37a	0.14a	1.28	0.79a	0.4455
(n = 7)	SD	4267	1172	0.25	0.27	0.01	0.01	0.03	0.01	0.1856
Group 3: PVA-PPy	Mean	40289	22588	3.03a	3.70	0.33a	0.12a	1.24	0.81a	0.5720
(n = 7)	SD	2686	3157	0.21	0.23	0.02	0.01	0.01	0.00	0.2565
Group 4: Graft	Mean	37041	21939	2.58	3.56	0.49	0.21	1.41	0.71	0.5936
(n = 4)	SD	1214	1302	0.06	0.08	0.02	0.01	0.02	0.01	0.0694
Group 5: End-to-end	Mean	38762	22729	2.65	3.58	0.47	0.19	1.38	0.73	0.5990
(n = 5)	SD	1524	2308	0.14	0.16	0.01	0.01	0.01	0.01	0.2082
Group 6: PVA-CNTs-MSCs	Mean	43373	25731	2.44	3.34	0.45ce	0.21ce	1.41	0.72ce	0.5942
(n = 7)	SD	3881	3386	0.20	0.21	0.06	0.04	0.08	0.01	0.1940

Density, total number, axon diameter (d), fiber diameter (D), myelin thickness (M), ratio myelin thickness and axon diameter (M/d), ratio fiber diameter and axon diameter (D/d), ratio axon diameter and fiber diameter (d/D, g-ratio) of regenerated sciatic nerve fibers at week-20 after neurotmesis. Values are presented as mean ± SD. n corresponds to the number of animals within each experimental group. PVA: Polyvinyl alcohol; CNTs: Carbon nanotubes; PPy: Polypyrrole.

^aP < 0.05 vs PVA-CNT-MSC;

^cP > 0.05 vs End-to-End;

^eP > 0.05 vs Graft.