Temporal Adaptive Changes in Contractility and Fatigability of Diaphragm Muscles from Streptozotocin-Diabetic Rats

Table 1

Contractile data from diaphragm of diabetic animals and age-matched controls.

Intact muscles
	4 days		4 weeks		8 weeks		14 weeks
	Control	Diabetic	Control	Diabetic	Control	Diabetic	Control	Diabetic	Insulin
	𝑛=7(4)	𝑛=7(4)	𝑛=9(5)	𝑛=8(4)	𝑛=10(5)	𝑛=10(5)	𝑛=7(4)	𝑛=7(4)	𝑛=8(4)
𝑇max (N/cm2)	25±2.2	18±1.2	25.5±2.5	22.9±1.5^b	24.8±2.1	20±2.2^c	25.3±1.1	15.2±1.2^d	24.7±2.3^e
Fatigue (% 𝑇max)	16±2	17±2	10±1.5	19.5±1^b	12±2	24±2^c	15±1	5±1^d	20±6^e
Recovery (% 𝑇max)	80±5	52±6^a	62±4	65±7	70±2	88±3^c	82±5	39±4^d	78±6^e
Skinned fibers
	𝑛=12(3)	𝑛=9(3)		𝑛=8(3)		𝑛=9(3)		𝑛=12(4)	𝑛=12(4)
𝐹max (N/cm2)	23±3.1	17.3±2.2^∗		21±1.1^#		19.5±1.8^#		14.5±2.8^∗	23.8±3.8^$
pCa50	5.62±0.03	5.46±0.05^∗		5.70±0.12^#		5.87±0.02^#		5.33±0.04^∗	5.63±0.07^$
𝑁	4.45±0.22	3.55±0.09^∗		3.25±0.22^#		2.85±0.12^#		3.35±0.20^∗	4.23±0.18^$

𝑛 represents the number of individual muscle preparations studied while the number in parenthesis indicates the number of animals from which the fibers were isolated.
a 𝑇_max and recovery decreased in diabetic muscles (𝑃<.05)
b 𝑇_max decreased and recovery enhanced in diabetic muscles (𝑃<.05)
c 𝑇_max decreased, fatigue reduced and recovery enhanced in diabetic muscles (𝑃<.05)
d 𝑇_max decreased, fatigue increased and recovery decreased in diabetic muscles (𝑃<.05)
e 𝑇_max, fatigue and recovery returned to control levels in diabetic muscles treated with insulin (𝑃<.05)
∗ 𝐹_max reduced, pCa50 reduced (less sensitive) and 𝑁 decreased (reduced cooperativity) in diabetic fibers (𝑃<.05)
# 𝐹_max reduced, pCa50 increased (more sensitive) and 𝑁 decreased (reduced cooperativity) in diabetic fibers (𝑃<.05)
$ 𝐹_max, pCa50 and 𝑁 returned to control levels in diabetic fibers treated with insulin (𝑃<.05).