CHANGES RELATED TO MUSCLE AUTOPHAGY AFTER EXHAUSTIVE EXERCISE AND BLUNT TRAUMA

Forty-two male SD rats were divided into 7 groups with 6 rats in each group: Quiet control group (C), immediately after exhaustive exercise (E0), 24 hours after exhaustive exercise (E24), 48 hours after exhaustive exercise (E48), immediately after blunt trauma (D0), 24 hours after blunt trauma (D24), 48 hours after blunt trauma (D48). All groups of rats were killed and samped respectively at different time points specified above, and the right gastrocnemius muscle was taken, which was divided into two parts, one for mRNAs of, Lamp-2, BNIP3 and NIX by real-time fluorescent quantitative PCR, and the other for p62 protein by Western blotting.

Results:

(1) Compared with group C, mRNA levels of p62, Lamp-2 and NIX in group E48 were significantly increased after exhaustive exercise(P<0.05), suggesting that autophagy increased in 48h after exhaustive exercise. (2) Compared with group C, p62mRNA and Lamp-2 mRNA levels were significantly increased immediately after blunt trauma(P<0.05) and decreased significantly in 48h after blunt trauma(P<0.05), suggesting that autophagy activity was enhanced immediately after blunt trauma and decreased in 48h after injury.

Conclusions:

Generally, there were differences at each recovery phase between blunt trauma and exhausted exercise models, and the basal autophagy factors and mitochondrial autophagy factors were also inconsistent. Basal autophagy factors p62 and Lamp-2 increased significantly 48 hours after eccentric exhaustive exercise and immediately after blunt trauma. Mitochondrial autophagy factor BNIP3 did not increase after exhaustive exercise and blunt trauma, but NIX only increased after exhaustive exercise. Its molecular mechanism needs to be further studied. Level of Evidence III; Therapeutic Studies Investigating the Results of Treatment.

Keywords:
Autophagy-Related Proteins; Muscle, Skeletal; Wounds, Nonpenetrating; Muscle Fatigue

group (n=6)	p62mRNA	Lamp-2 mRNA	BNIP3 mRNA	NIX mRNA
C	1.00±0.30	1.00±0.49	1.00±0.17	1.00±0.39
E0	0.81±0.14	0.43±0.27^* * Significant difference compared with control, P < 0.05.	0.33±0.30^* * Significant difference compared with control, P < 0.05.	0.59±0.22^* * Significant difference compared with control, P < 0.05.
E24	0.83±0.39	0.38±0.19^* * Significant difference compared with control, P < 0.05.	0.53±0.49^* * Significant difference compared with control, P < 0.05.	1.38±0.32^* * Significant difference compared with control, P < 0.05. ^# # Significant difference compared with E0, P < 0.05.
E48	2.71±0.57 ^* * Significant difference compared with control, P < 0.05. ^# # Significant difference compared with E0, P < 0.05.	1.26±0.46^* * Significant difference compared with control, P < 0.05. ^# # Significant difference compared with E0, P < 0.05.	0.77±0.23^# # Significant difference compared with E0, P < 0.05.	1.29±0.17^* * Significant difference compared with control, P < 0.05. ^# # Significant difference compared with E0, P < 0.05.
D0	5.59±0.84 ^* * Significant difference compared with control, P < 0.05.	1.90±0.62 ^* * Significant difference compared with control, P < 0.05.	1.04±0.29	0.79±0.25
D24	1.74±0.49 ^* * Significant difference compared with control, P < 0.05.	0.42±0.25 ^* * Significant difference compared with control, P < 0.05. ^& & Significant difference compared with D0, P < 0.05.	0.31±0.28^* * Significant difference compared with control, P < 0.05. ^& & Significant difference compared with D0, P < 0.05.	0.39±0.26^* * Significant difference compared with control, P < 0.05. ^& & Significant difference compared with D0, P < 0.05.
D48	0.22±0.15 ^* * Significant difference compared with control, P < 0.05. ^&& && P < 0.01. n = 6/group.	0.21±0.19^* * Significant difference compared with control, P < 0.05. ^&& && P < 0.01. n = 6/group.	0.05±0.34^* * Significant difference compared with control, P < 0.05. ^&& && P < 0.01. n = 6/group.	0.29±0.13^* * Significant difference compared with control, P < 0.05. ^& & Significant difference compared with D0, P < 0.05.

group (n=6)	Protein expression of p62
C	0.5098±0.2286
E0	0.5301±0.1697
E24	0.5689±0.1588
E48	0.7012±0.2409^* * Significant difference compared with control, P < 0.05. ^# # Significant difference compared with E0, P < 0.05.
D0	0.5902±0.2089
D24	0.5697±0.1803
D48	0.5778±0.1279

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[1] Correspondence: Tongbin Pan YangZhou University, College of Physical Education. Yangzhou, Jiangsu, China. 225009. panlichina@sina.com

P62	FORWARD: CCAGCACAGGCACAGAAGACAAG
	REVERSE: TGAGCCAGCCGCCTTCATCC
Lamp-2	FORWARD: CCTAGGAGCCGTTCAGTCCA
	REVERSE: GCCCAAGAGACAGCGAATCC
BNIP3	FORWARD: AGCGTTCCAGCCTCCGTCTC
	REVERSE: GAGAGTAGCTGTGCGCTTCGG
NIX	FORWARD: GTTCCTTCCTCGTCTTCCATCCAC
	REVERSE: GGCTCCACTCTTCCTCATGCTTAG
GAPDH	FORWARD: AATGGTGAAGGTCGG TGTGAACG
	REVERSE: TCGCTCCTGGAAGATGGTGATGG